OpenCodeAdapterV2.ts

import type {
  Event as OpenCodeEvent,
  Message as OpenCodeMessage,
  Part as OpenCodePart,
  PermissionRequest,
  PermissionRuleset,
  QuestionRequest,
  Session as OpenCodeSession,
  Todo as OpenCodeTodo,
  ToolPart,
} from "@opencode-ai/sdk/v2";
import { HostProcessEnvironment } from "@t3tools/shared/hostProcess";
import { getModelSelectionStringOptionValue } from "@t3tools/shared/model";
import { causeErrorTag } from "@t3tools/shared/observability";
import {
  defaultInstanceIdForDriver,
  type ModelSelection,
  type OpenCodeSettings,
  type OrchestrationV2AppThread,
  type OrchestrationV2ConversationMessage,
  type OrchestrationV2ExecutionNode,
  type OrchestrationV2PlanStep,
  type OrchestrationV2ProviderCapabilities,
  type OrchestrationV2ProviderFailure,
  type OrchestrationV2ProviderRef,
  type OrchestrationV2ProviderSession,
  type OrchestrationV2ProviderThread,
  type OrchestrationV2ProviderTurn,
  type OrchestrationV2RuntimeRequest,
  type OrchestrationV2Subagent,
  type OrchestrationV2TurnItem,
  OpenCodeSettings as OpenCodeSettingsSchema,
  type PlanId,
  ProviderDriverKind,
  type ProviderInstanceId,
  type ProviderRequestKind,
  type ProviderSessionId,
  type RuntimeRequestId,
  type ThreadId,
} from "@t3tools/contracts";
import * as Cause from "effect/Cause";
import * as DateTime from "effect/DateTime";
import * as Deferred from "effect/Deferred";
import * as Duration from "effect/Duration";
import * as Effect from "effect/Effect";
import * as Exit from "effect/Exit";
import * as Fiber from "effect/Fiber";
import * as Layer from "effect/Layer";
import * as Option from "effect/Option";
import * as Queue from "effect/Queue";
import * as Random from "effect/Random";
import * as Schema from "effect/Schema";
import * as Semaphore from "effect/Semaphore";
import * as Scope from "effect/Scope";
import * as Stream from "effect/Stream";

import { resolveAttachmentPath } from "../../attachmentStore.ts";
import * as ServerConfig from "../../config.ts";
import * as McpProviderSession from "../../mcp/McpProviderSession.ts";
import type { EventNdjsonLogger } from "../../provider/Layers/EventNdjsonLogger.ts";
import * as ProviderEventLoggers from "../../provider/Layers/ProviderEventLoggers.ts";
import {
  structuralProtocolMethod,
  summarizeNativeProtocolPayload,
} from "../../provider/NativeProtocolLogging.ts";
import { mergeProviderInstanceEnvironment } from "../../provider/ProviderInstanceEnvironment.ts";
import { t3OrchestrationSystemPrompt } from "../../provider/T3OrchestrationInstructions.ts";
import { buildRuntimeInstructions } from "../../provider/RuntimeInstructions.ts";
import * as OpenCodeRuntime from "../../provider/opencodeRuntime.ts";
import * as IdAllocator from "../IdAllocator.ts";
import { makeProviderFailure } from "../ProviderFailure.ts";
import { turnScopedSelectionTransition } from "../ProviderSelectionTransition.ts";
import { providerMessageTextWithAttachmentPaths } from "../AttachmentPrompt.ts";
import * as ProviderAdapter from "../ProviderAdapter.ts";
import {
  ProviderAdapterDriverCreateError,
  type ProviderAdapterDriver,
  type ProviderAdapterDriverCreateInput,
} from "../ProviderAdapterDriver.ts";
import { makeSubagentChildThread, subagentThreadTitle } from "../SubagentProjection.ts";
import { openCodeToolTurnItem } from "./OpenCodeToolItems.ts";

export { openCodeToolProjectionKind } from "./OpenCodeToolItems.ts";

export const OPENCODE_PROVIDER = ProviderDriverKind.make("opencode");
export const OPENCODE_DEFAULT_INSTANCE_ID = defaultInstanceIdForDriver(OPENCODE_PROVIDER);
export const OPENCODE_SDK_PROTOCOL = "opencode-sdk.sse" as const;
const DEFAULT_OPENCODE_SETTINGS = Schema.decodeSync(OpenCodeSettingsSchema)({});

let openCodeMessageIdEpochMillis = -1;
let openCodeMessageIdCounter = 0;

const makeOpenCodeMessageId = Effect.fnUntraced(function* () {
  const epochMillis = DateTime.toEpochMillis(yield* DateTime.now);
  if (epochMillis !== openCodeMessageIdEpochMillis) {
    openCodeMessageIdEpochMillis = epochMillis;
    openCodeMessageIdCounter = 0;
  }
  openCodeMessageIdCounter += 1;
  const encodedTime = BigInt.asUintN(
    48,
    BigInt(epochMillis) * 0x1000n + BigInt(openCodeMessageIdCounter),
  )
    .toString(16)
    .padStart(12, "0");
  const alphabet = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
  const random = (yield* Effect.forEach(Array.from({ length: 28 }), () =>
    Random.nextIntBetween(0, alphabet.length - 1),
  ))
    .map((index) => alphabet[index])
    .join("");
  return `msg_${encodedTime}${random}`;
});

/**
 * OpenCode's session, message, part, and interaction-request identifiers are
 * durable. It does not expose a first-class turn object: the initiating user
 * message is the best native turn correlation point, and session idle is the
 * authoritative terminal signal.
 */
const OpenCodeProviderCapabilitiesV2 = {
  sessions: {
    // The current adapter owns one directory-bound client/server per session.
    // Keep it isolated until its runtime is made safe for cross-thread pooling.
    supportsMultipleProviderThreadsPerSession: false,
    supportsModelSwitchInSession: true,
    supportsProviderSwitchingViaHandoff: true,
    supportsRuntimeModeSwitchInSession: false,
    pendingRequestsSurviveRestart: false,
  },
  threads: {
    canCreateEmptyThread: true,
    canReadThreadSnapshot: true,
    canRollbackThread: true,
    canForkThread: true,
    canForkFromTurn: true,
    canForkFromSubagentThread: true,
    exposesNativeThreadId: true,
  },
  turns: {
    exposesNativeTurnId: false,
    emitsTurnStarted: true,
    emitsTurnCompleted: true,
    supportsInterrupt: true,
    supportsActiveSteering: true,
    supportsSteeringByInterruptRestart: true,
    supportsQueuedMessages: true,
    terminalStatusQuality: "strong",
  },
  streaming: {
    streamsAssistantText: true,
    streamsReasoning: true,
    streamsToolOutput: true,
    streamsPlanText: false,
    emitsMessageCompleted: true,
  },
  tools: {
    exposesToolItemIds: true,
    emitsToolStarted: true,
    emitsToolCompleted: true,
    emitsToolOutput: true,
    supportsMcpTools: true,
    supportsDynamicToolCallbacks: false,
  },
  approvals: {
    supportsCommandApproval: true,
    supportsFileReadApproval: true,
    supportsFileChangeApproval: true,
    supportsApplyPatchApproval: true,
    approvalsHaveNativeRequestIds: true,
    approvalCallbacksAreLiveOnly: true,
    approvalsCanOriginateFromSubagents: true,
  },
  planning: {
    emitsPlanUpdated: true,
    emitsTodoList: true,
    emitsProposedPlan: false,
    supportsStructuredQuestions: true,
    planDeltasHaveItemIds: false,
  },
  subagents: {
    supportsSubagents: true,
    exposesSubagentThreadIds: true,
    emitsSubagentLifecycle: true,
    canWaitForSubagents: true,
    canCloseSubagents: false,
    canForkSubagentThread: true,
  },
  context: {
    acceptsSystemContext: false,
    acceptsDeveloperContext: false,
    acceptsSyntheticUserContext: true,
    canGenerateSummaries: true,
    canConsumeHandoffSummaries: true,
    supportsDeltaHandoff: true,
    supportsFullThreadHandoff: true,
    maxRecommendedHandoffChars: null,
  },
  checkpointing: {
    appCanCheckpointFilesystem: true,
    supportsNestedCheckpointScopes: true,
    providerCanRollbackConversation: true,
    providerRollbackReturnsSnapshot: true,
    providerCanReadConversationSnapshot: true,
  },
  identity: {
    nativeThreadIds: "strong",
    nativeTurnIds: "weak",
    nativeItemIds: "strong",
    nativeRequestIds: "strong",
  },
  runtimePolicy: {
    enforcement: "native",
  },
} satisfies OrchestrationV2ProviderCapabilities;

type TerminalTurnStatus = Extract<
  OrchestrationV2ProviderTurn["status"],
  "completed" | "interrupted" | "failed" | "cancelled"
>;

type OpenCodeStepUsage = Pick<
  Extract<OpenCodePart, { readonly type: "step-finish" }>,
  "id" | "tokens"
>;

interface OpenCodeTurnTokenUsageAccumulator {
  readonly partIds: Set<string>;
  readonly promptMessageIds: Set<string>;
  readonly assistantOwnershipByMessageId: Map<string, "owned" | "other" | "unknown">;
  // Native removal does not undo usage. Keep unresolved counts until this turn settles.
  readonly unresolvedStepsByMessageId: Map<string, Map<string, OpenCodeStepUsage>>;
  inputTokens: number;
  cachedInputTokens: number;
  cacheCreationTokens: number;
  outputTokens: number;
  reasoningTokens: number;
  hasSubagents: boolean;
  complete: boolean;
}

function makeOpenCodeTurnTokenUsageAccumulator(): OpenCodeTurnTokenUsageAccumulator {
  return {
    partIds: new Set(),
    promptMessageIds: new Set(),
    assistantOwnershipByMessageId: new Map(),
    unresolvedStepsByMessageId: new Map(),
    inputTokens: 0,
    cachedInputTokens: 0,
    cacheCreationTokens: 0,
    outputTokens: 0,
    reasoningTokens: 0,
    hasSubagents: false,
    complete: true,
  };
}

function accumulateOpenCodeStepUsage(
  accumulator: OpenCodeTurnTokenUsageAccumulator,
  part: OpenCodeStepUsage,
): void {
  if (accumulator.partIds.has(part.id)) return;
  accumulator.partIds.add(part.id);
  accumulator.inputTokens += part.tokens.input + part.tokens.cache.read + part.tokens.cache.write;
  accumulator.cachedInputTokens += part.tokens.cache.read;
  accumulator.cacheCreationTokens += part.tokens.cache.write;
  accumulator.outputTokens += part.tokens.output + part.tokens.reasoning;
  accumulator.reasoningTokens += part.tokens.reasoning;
}

interface ActiveOpenCodeTurn {
  readonly usage: OpenCodeTurnTokenUsageAccumulator;
  readonly isRoot: boolean;
  readonly threadId: ThreadId;
  readonly runId: ProviderAdapter.ProviderAdapterV2TurnInput["runId"] | null;
  readonly rootNodeId: ProviderAdapter.ProviderAdapterV2TurnInput["rootNodeId"];
  readonly appThread: OrchestrationV2AppThread;
  readonly modelSelection: ModelSelection;
  readonly runtimePolicy: ProviderAdapter.ProviderAdapterV2RuntimePolicy;
  readonly providerTurnId: OrchestrationV2ProviderTurn["id"];
  readonly providerTurnOrdinal: number;
  readonly runOrdinal: number;
  readonly runAttemptId: OrchestrationV2ProviderTurn["runAttemptId"];
  readonly startedAt: DateTime.Utc;
  readonly itemOrdinals: Map<string, number>;
  readonly parts: Map<string, Exclude<OpenCodePart, ToolPart>>;
  readonly partIdsByMessage: Map<string, Set<string>>;
  readonly toolNamesByCallId: Map<string, string>;
  readonly providerTurn: OrchestrationV2ProviderTurn;
  nextItemOrdinal: number;
  nativeUserMessageId: string | null;
  admissionMessageId: string | null;
  interrupted: boolean;
  finalized: boolean;
  planId: PlanId | null;
  admissionGeneration: number;
  admissionReconciliationGeneration: number | null;
  admissionPending: boolean;
  admissionAccepted: boolean;
  admissionMessageObserved: boolean;
  idleDuringAdmission: boolean;
  admissionSettled: Deferred.Deferred<void>;
  admissionAbortController: AbortController | null;
}

type OpenCodeAdmissionSignal =
  | "accepted"
  | "assistant-completed"
  | "busy"
  | "idle"
  | "user-message";
type OpenCodeAdmissionAction = "hold" | "reconcile-idle" | "release";

export function advanceOpenCodePromptAdmission(
  admission: Pick<
    ActiveOpenCodeTurn,
    "admissionAccepted" | "admissionMessageObserved" | "admissionPending" | "idleDuringAdmission"
  >,
  signal: OpenCodeAdmissionSignal,
): OpenCodeAdmissionAction {
  if (!admission.admissionPending) return "release";
  if (signal === "assistant-completed") {
    admission.admissionAccepted = true;
    admission.admissionMessageObserved = true;
    admission.admissionPending = false;
    return "release";
  }
  if (signal === "idle") {
    admission.idleDuringAdmission = true;
    return "hold";
  }
  if (signal === "accepted") admission.admissionAccepted = true;
  if (signal === "busy" || signal === "user-message") admission.admissionMessageObserved = true;
  if (!admission.admissionAccepted || !admission.admissionMessageObserved) return "hold";
  if (admission.idleDuringAdmission) return "reconcile-idle";
  admission.admissionPending = false;
  return "release";
}

export function cancelOpenCodePromptAdmission(
  admission: Pick<ActiveOpenCodeTurn, "admissionGeneration" | "admissionPending">,
  nextGeneration: number,
): void {
  admission.admissionGeneration = nextGeneration;
  admission.admissionPending = false;
}

export const reconcileOpenCodePromptAdmissionStatus = Effect.fn(
  "reconcileOpenCodePromptAdmissionStatus",
)(function* (
  admission: Pick<ActiveOpenCodeTurn, "admissionGeneration" | "admissionPending">,
  generation: number,
  readStatus: Effect.Effect<"busy" | "idle" | "unknown">,
) {
  if (admission.admissionGeneration !== generation || !admission.admissionPending) {
    return "stale" as const;
  }
  const status = yield* readStatus;
  if (admission.admissionGeneration !== generation || !admission.admissionPending) {
    return "stale" as const;
  }
  if (status !== "unknown") admission.admissionPending = false;
  return status;
});

interface OpenCodeSubagentContext {
  readonly nativeItemId: string;
  readonly nodeId: OrchestrationV2Subagent["id"];
  readonly parentState: OpenCodeThreadState;
  readonly parentTurn: ActiveOpenCodeTurn;
  readonly prompt: string;
  readonly title: string | null;
  readonly startedAt: DateTime.Utc;
  childSessionId: string | null;
  childThreadId: ThreadId | null;
  childProviderThreadId: OrchestrationV2ProviderThread["id"] | null;
  model: string | null;
  result: string | null;
}

interface OpenCodeThreadState {
  readonly nativeSessionId: string;
  providerThread: OrchestrationV2ProviderThread;
  appThread: OrchestrationV2AppThread | null;
  activeTurn: ActiveOpenCodeTurn | null;
  readonly providerTurns: Map<string, OrchestrationV2ProviderTurn>;
  readonly messages: Map<string, OrchestrationV2ConversationMessage>;
  readonly runtimeRequests: Map<string, OrchestrationV2RuntimeRequest>;
  readonly messageRoles: Map<string, "user" | "assistant">;
  readonly userMessageIds: Array<string>;
  parentSubagent: OpenCodeSubagentContext | null;
  nextChildTurnOrdinal: number;
  nextAdmissionGeneration: number;
}

interface OpenCodeRequestOwner {
  readonly state: OpenCodeThreadState;
  readonly turn: ActiveOpenCodeTurn;
  /** The subagent on the owner's thread that leads to the asking session. */
  readonly subagent: OpenCodeSubagentContext | null;
}

/**
 * The top-level thread and active turn that own a session's requests, walking
 * up through (possibly nested) subagents.
 */
function topLevelRequestOwner(state: OpenCodeThreadState): OpenCodeRequestOwner | undefined {
  let owner = state;
  let subagent: OpenCodeSubagentContext | null = null;
  while (owner.parentSubagent !== null) {
    subagent = owner.parentSubagent;
    owner = subagent.parentState;
  }
  return owner.activeTurn === null ? undefined : { state: owner, turn: owner.activeTurn, subagent };
}

interface PendingOpenCodeRequest {
  readonly requestId: RuntimeRequestId;
  readonly nativeRequestId: string;
  /** The session that asked, which may be a subagent's. */
  readonly nativeSessionId: string;
  readonly turn: ActiveOpenCodeTurn;
  readonly state: OpenCodeThreadState;
  readonly nodeId: OrchestrationV2ExecutionNode["id"];
  readonly parentNodeId: OrchestrationV2ExecutionNode["id"];
  readonly turnItemId: OrchestrationV2TurnItem["id"];
  readonly requestKind: OpenCodePermissionRequestKind | "user_input";
  readonly createdAt: DateTime.Utc;
  readonly permission?: PermissionRequest;
  readonly question?: QuestionRequest;
}

export interface OpenCodeAdapterV2Options {
  readonly instanceId: ProviderInstanceId;
  readonly settings: OpenCodeSettings;
  readonly environment: NodeJS.ProcessEnv;
  readonly runtime: OpenCodeRuntime.OpenCodeRuntimeShape;
  readonly idAllocator: IdAllocator.IdAllocatorV2Shape;
  readonly serverConfig: ServerConfig.ServerConfig["Service"];
  readonly nativeEventLogger?: EventNdjsonLogger;
}

export interface OpenCodeProtocolLogEvent {
  readonly direction: "incoming" | "outgoing";
  readonly messageKind: "request" | "response" | "notification" | "error";
  readonly method: string;
  readonly payload: unknown;
}

function formatOpenCodeProtocolLogPayload(event: OpenCodeProtocolLogEvent) {
  return {
    direction: event.direction,
    messageKind: event.messageKind,
    method: structuralProtocolMethod(event.method),
    payload: summarizeNativeProtocolPayload(event.payload),
  };
}

export function makeOpenCodeProtocolLogger(input: {
  readonly nativeEventLogger: EventNdjsonLogger | undefined;
  readonly idAllocator: IdAllocator.IdAllocatorV2Shape;
  readonly providerInstanceId: ProviderInstanceId;
  readonly providerSessionId: ProviderSessionId;
  readonly threadId: ThreadId;
}): (event: OpenCodeProtocolLogEvent) => Effect.Effect<void, never> {
  return (event) =>
    Effect.gen(function* () {
      if (!input.nativeEventLogger) return;
      const observedAt = DateTime.formatIso(yield* DateTime.now);
      const method = structuralProtocolMethod(event.method);
      yield* input.nativeEventLogger.write(
        {
          observedAt,
          event: {
            id: yield* input.idAllocator.allocate.rawEvent({
              providerSessionId: input.providerSessionId,
              method,
            }),
            kind: "protocol",
            protocol: OPENCODE_SDK_PROTOCOL,
            provider: OPENCODE_PROVIDER,
            providerInstanceId: input.providerInstanceId,
            providerSessionId: input.providerSessionId,
            createdAt: observedAt,
            threadId: input.threadId,
            payload: formatOpenCodeProtocolLogPayload(event),
          },
        },
        input.threadId,
      );
    }).pipe(
      Effect.catchCause((cause) =>
        Cause.hasInterrupts(cause)
          ? Effect.interrupt
          : Effect.logWarning("Failed to write native OpenCode event log.", {
              errorTag: causeErrorTag(cause),
              reasonCount: cause.reasons.length,
              provider: OPENCODE_PROVIDER,
              threadId: input.threadId,
            }),
      ),
    );
}

function protocolError(
  detail: string,
  payload?: unknown,
): ProviderAdapter.ProviderAdapterProtocolError {
  return new ProviderAdapter.ProviderAdapterProtocolError({
    driver: OPENCODE_PROVIDER,
    detail,
    ...(payload === undefined ? {} : { payload }),
  });
}

function nativeThreadId(providerThread: OrchestrationV2ProviderThread): string {
  const nativeId = providerThread.nativeThreadRef?.nativeId;
  if (nativeId === null || nativeId === undefined) {
    throw protocolError(`Provider thread ${providerThread.id} has no OpenCode session id`);
  }
  return nativeId;
}

function dateTimeFromEpoch(value: number | undefined, fallback: DateTime.Utc): DateTime.Utc {
  if (value === undefined) return fallback;
  return Option.getOrElse(DateTime.make(value), () => fallback);
}

function nonEmptyString(value: unknown): string | undefined {
  return typeof value === "string" && value.trim().length > 0 ? value : undefined;
}

function recordValue(input: unknown, key: string): unknown {
  return typeof input === "object" && input !== null && key in input
    ? (input as Record<string, unknown>)[key]
    : undefined;
}

function recordString(input: unknown, ...keys: ReadonlyArray<string>): string | undefined {
  for (const key of keys) {
    const value = nonEmptyString(recordValue(input, key));
    if (value !== undefined) return value;
  }
  return undefined;
}

function sdkResponseForRawLog(value: unknown): unknown {
  if (typeof value !== "object" || value === null) return value;
  if ("data" in value) return { data: (value as { readonly data?: unknown }).data ?? null };
  if ("stream" in value) return { subscribed: true };
  return value;
}

type OpenCodePermissionRequestKind = Extract<
  ProviderRequestKind,
  "command" | "file-read" | "file-change"
>;

export function openCodePermissionRequestKind(
  permission: string,
  toolName?: string,
): OpenCodePermissionRequestKind {
  const normalized = permission.toLowerCase();
  const normalizedTool = toolName?.toLowerCase() ?? "";
  if (
    normalized === "edit" ||
    normalized === "write" ||
    normalized === "patch" ||
    normalized === "apply_patch" ||
    normalizedTool === "edit" ||
    normalizedTool === "write" ||
    normalizedTool === "patch" ||
    normalizedTool === "apply_patch"
  ) {
    return "file-change";
  }
  if (
    normalized === "read" ||
    normalized === "glob" ||
    normalized === "grep" ||
    normalized === "lsp" ||
    normalized === "external_directory" ||
    normalizedTool === "read" ||
    normalizedTool.includes("glob") ||
    normalizedTool.includes("grep") ||
    normalizedTool.includes("search")
  ) {
    return "file-read";
  }
  return "command";
}

const OPENCODE_ALWAYS_ALLOWED_PERMISSIONS = [
  "question",
  "read",
  "glob",
  "grep",
  "lsp",
  "todowrite",
  "task",
  "skill",
] as const;

const OPENCODE_RESTRICTED_PERMISSIONS = [
  "bash",
  "edit",
  "webfetch",
  "websearch",
  "codesearch",
  "external_directory",
  "doom_loop",
] as const;

/**
 * OpenCode does not provide an OS sandbox, so permission rules are also the
 * enforcement boundary for non-interactive policies. Read/planning tools are
 * safe by default; edits are auto-approved only for workspace-write modes,
 * while shell/network/external access remains gated unless policy explicitly
 * allows it.
 */
export function openCodePermissionRules(
  runtimePolicy: ProviderAdapter.ProviderAdapterV2RuntimePolicy,
): PermissionRuleset {
  const sandboxPolicy = recordValue(runtimePolicy, "sandboxPolicy");
  const sandboxType = recordString(sandboxPolicy, "type");
  const rawApprovalPolicy = runtimePolicy.approvalPolicy;
  const approvalPolicy = nonEmptyString(rawApprovalPolicy);
  const requiresApproval =
    approvalPolicy === undefined
      ? (typeof rawApprovalPolicy === "object" && rawApprovalPolicy !== null) ||
        runtimePolicy.runtimeMode !== "full-access"
      : approvalPolicy !== "never";
  const externallySandboxed = sandboxType === "externalSandbox";
  const dangerFullAccess = sandboxType === "dangerFullAccess";
  const implicitFullAccess =
    sandboxType === undefined && runtimePolicy.runtimeMode === "full-access";

  if (!requiresApproval && (externallySandboxed || dangerFullAccess || implicitFullAccess)) {
    return [{ permission: "*", pattern: "*", action: "allow" }];
  }

  // Task sessions initially inherit only parent deny rules. Seed explicit
  // denies before the effective ask/allow overrides so a child is safe during
  // the short interval before emitSubagent installs its complete policy.
  const rules: PermissionRuleset = [
    { permission: "*", pattern: "*", action: "deny" },
    ...OPENCODE_RESTRICTED_PERMISSIONS.map((permission) => ({
      permission,
      pattern: "*",
      action: "deny" as const,
    })),
  ];

  if (requiresApproval) {
    rules.push({ permission: "*", pattern: "*", action: "ask" });
    for (const permission of OPENCODE_RESTRICTED_PERMISSIONS) {
      rules.push({ permission, pattern: "*", action: "ask" });
    }
  }

  rules.push(
    ...OPENCODE_ALWAYS_ALLOWED_PERMISSIONS.map((permission) => ({
      permission,
      pattern: "*",
      action: "allow" as const,
    })),
  );

  rules.push(
    { permission: "read", pattern: "*.env", action: requiresApproval ? "ask" : "deny" },
    { permission: "read", pattern: "*.env.*", action: requiresApproval ? "ask" : "deny" },
    { permission: "read", pattern: "*.env.example", action: "allow" },
  );

  if (
    runtimePolicy.runtimeMode === "auto-accept-edits" ||
    (!requiresApproval && sandboxType === "workspaceWrite")
  ) {
    rules.push({ permission: "edit", pattern: "*", action: "allow" });
  }

  if (!requiresApproval && recordValue(sandboxPolicy, "networkAccess") === true) {
    for (const permission of ["webfetch", "websearch", "codesearch"] as const) {
      rules.push({ permission, pattern: "*", action: "allow" });
    }
  }

  if (!requiresApproval && sandboxType === "readOnly") {
    const access = recordValue(sandboxPolicy, "access");
    if (recordString(access, "type") === "fullAccess") {
      rules.push({ permission: "external_directory", pattern: "*", action: "allow" });
    }
  }

  if (!requiresApproval && sandboxType === "workspaceWrite") {
    const writableRoots = recordValue(sandboxPolicy, "writableRoots");
    if (Array.isArray(writableRoots)) {
      for (const root of writableRoots) {
        if (typeof root === "string" && root.trim().length > 0) {
          rules.push({
            permission: "external_directory",
            pattern: `${root.replace(/\/$/, "")}/*`,
            action: "allow",
          });
        }
      }
    }
  }

  return rules;
}

function permissionRuleEquals(
  left: PermissionRuleset[number],
  right: PermissionRuleset[number],
): boolean {
  return (
    left.permission === right.permission &&
    left.pattern === right.pattern &&
    left.action === right.action
  );
}

/**
 * OpenCode task sessions inherit only the parent's deny/external-directory
 * rules and then add agent-specific restrictions such as disabling nested
 * tasks. Install the complete parent policy while retaining only rules that
 * were added specifically for the selected child agent.
 */
export function openCodeChildPermissionRules(
  runtimePolicy: ProviderAdapter.ProviderAdapterV2RuntimePolicy,
  nativeChildRules: PermissionRuleset,
): PermissionRuleset {
  const parentRules = openCodePermissionRules(runtimePolicy);
  const inheritedRules = parentRules.filter(
    (rule) => rule.permission === "external_directory" || rule.action === "deny",
  );
  const childSpecificRules = nativeChildRules.filter(
    (childRule) =>
      !inheritedRules.some((inheritedRule) => permissionRuleEquals(childRule, inheritedRule)),
  );
  return [...parentRules, ...childSpecificRules];
}

/**
 * OpenCode's fork/revert boundary is exclusive. To retain the selected app
 * turn, address the next native user message; omitting a boundary retains the
 * current head when the selected turn is already last.
 */
export function openCodeBoundaryAfterProviderTurn(
  providerTurns: ReadonlyArray<OrchestrationV2ProviderTurn>,
  selectedProviderTurnId: OrchestrationV2ProviderTurn["id"],
): string | undefined {
  const selected = providerTurns.find((turn) => turn.id === selectedProviderTurnId);
  if (selected === undefined) return undefined;
  return providerTurns
    .filter((turn) => turn.ordinal > selected.ordinal)
    .toSorted((left, right) => left.ordinal - right.ordinal)
    .map((turn) => turn.nativeTurnRef?.nativeId)
    .find((nativeId): nativeId is string => nativeId !== null && nativeId !== undefined);
}

function toolStatus(part: ToolPart): {
  readonly node: OrchestrationV2ExecutionNode["status"];
  readonly item: OrchestrationV2TurnItem["status"];
} {
  switch (part.state.status) {
    case "pending":
      return { node: "pending", item: "pending" };
    case "running":
      return { node: "running", item: "running" };
    case "completed":
      return { node: "completed", item: "completed" };
    case "error":
      return { node: "failed", item: "failed" };
  }
}

function toolInput(part: ToolPart): Record<string, unknown> {
  return part.state.input;
}

function toolOutput(part: ToolPart): string | undefined {
  if (part.state.status === "completed") return part.state.output;
  if (part.state.status === "error") return part.state.error;
  return undefined;
}

function toolStartedAt(part: ToolPart, now: DateTime.Utc): DateTime.Utc {
  return dateTimeFromEpoch(
    part.state.status === "pending" ? undefined : part.state.time.start,
    now,
  );
}

function toolCompletedAt(part: ToolPart, now: DateTime.Utc): DateTime.Utc | null {
  return part.state.status === "completed" || part.state.status === "error"
    ? dateTimeFromEpoch(part.state.time.end, now)
    : null;
}

function toolTitle(part: ToolPart): string | null {
  return part.state.status === "running" || part.state.status === "completed"
    ? (part.state.title ?? null)
    : null;
}

function toolModel(part: ToolPart): string | null {
  const metadata =
    part.state.status === "running" ||
    part.state.status === "completed" ||
    part.state.status === "error"
      ? part.state.metadata
      : undefined;
  const model = recordValue(metadata, "model");
  const providerId = recordString(model, "providerID", "providerId");
  const modelId = recordString(model, "modelID", "modelId", "id");
  return providerId !== undefined && modelId !== undefined ? `${providerId}/${modelId}` : null;
}

function taskSessionId(part: ToolPart): string | null {
  const metadata =
    part.state.status === "running" ||
    part.state.status === "completed" ||
    part.state.status === "error"
      ? part.state.metadata
      : undefined;
  return recordString(metadata, "sessionId", "sessionID") ?? null;
}

function makeProviderThread(input: {
  readonly idAllocator: IdAllocator.IdAllocatorV2Shape;
  readonly providerInstanceId: ProviderInstanceId;
  readonly providerSessionId: OrchestrationV2ProviderThread["providerSessionId"];
  readonly appThreadId: OrchestrationV2ProviderThread["appThreadId"];
  readonly ownerNodeId?: OrchestrationV2ProviderThread["ownerNodeId"];
  readonly nativeSession: OpenCodeSession;
  readonly forkedFrom?: OrchestrationV2ProviderThread["forkedFrom"];
  readonly now: DateTime.Utc;
}): OrchestrationV2ProviderThread {
  const createdAt = dateTimeFromEpoch(input.nativeSession.time.created, input.now);
  return {
    id: input.idAllocator.derive.providerThread({
      driver: OPENCODE_PROVIDER,
      nativeThreadId: input.nativeSession.id,
    }),
    driver: OPENCODE_PROVIDER,
    providerInstanceId: input.providerInstanceId,
    providerSessionId: input.providerSessionId,
    appThreadId: input.appThreadId,
    ownerNodeId: input.ownerNodeId ?? null,
    nativeThreadRef: {
      driver: OPENCODE_PROVIDER,
      nativeId: input.nativeSession.id,
      strength: "strong",
    },
    nativeConversationHeadRef: null,
    status: "idle",
    firstRunOrdinal: null,
    lastRunOrdinal: null,
    handoffIds: [],
    forkedFrom: input.forkedFrom ?? null,
    createdAt,
    updatedAt: dateTimeFromEpoch(input.nativeSession.time.updated, input.now),
  };
}

function providerRef(nativeId: string, strength: "strong" | "weak" = "strong") {
  return {
    driver: OPENCODE_PROVIDER,
    nativeId,
    strength,
  } satisfies OrchestrationV2ProviderRef;
}

function openCodeErrorMessage(event: Extract<OpenCodeEvent, { type: "session.error" }>): string {
  const error = event.properties.error;
  if (error === undefined) return "OpenCode session failed without an error payload.";
  return recordString(error.data, "message") ?? error.name;
}

function terminalStatusForError(
  event: Extract<OpenCodeEvent, { type: "session.error" }>,
  turn: ActiveOpenCodeTurn,
): TerminalTurnStatus {
  return turn.interrupted || isMessageAbortedError(event) ? "interrupted" : "failed";
}

function isMessageAbortedError(event: Extract<OpenCodeEvent, { type: "session.error" }>): boolean {
  return event.properties.error?.name === "MessageAbortedError";
}

function isOpenCodeNotFound(cause: unknown): boolean {
  const seen = new Set<unknown>();
  const queue: Array<unknown> = [cause];
  for (let steps = 0; queue.length > 0 && steps < 32; steps += 1) {
    const node = queue.shift();
    if (node === null || typeof node !== "object" || seen.has(node)) {
      continue;
    }
    seen.add(node);
    const record = node as Record<string, unknown>;

    const response = record.response;
    const statuses = [
      record.status,
      record.statusCode,
      response !== null && typeof response === "object"
        ? (response as { readonly status?: unknown }).status
        : undefined,
    ].filter((status): status is number => typeof status === "number");
    if (statuses.includes(404)) {
      return true;
    }
    if (statuses.length > 0) {
      continue;
    }

    const name = record.name;
    if (typeof name === "string" && name.toLowerCase() === "notfounderror") {
      return true;
    }

    for (const key of ["cause", "body", "error", "data"] as const) {
      if (record[key] !== undefined) {
        queue.push(record[key]);
      }
    }
  }
  return false;
}

function unwrapData<A>(operation: string, result: { readonly data?: A }): NonNullable<A> {
  if (result.data === undefined) {
    throw new OpenCodeRuntime.OpenCodeRuntimeError({
      operation,
      detail: `OpenCode ${operation} returned no response payload.`,
    });
  }
  return result.data as NonNullable<A>;
}

export function makeOpenCodeAdapterV2(
  options: OpenCodeAdapterV2Options,
): ProviderAdapter.ProviderAdapterV2Shape {
  const { idAllocator, runtime, serverConfig } = options;

  return ProviderAdapter.ProviderAdapterV2.of({
    instanceId: options.instanceId,
    driver: OPENCODE_PROVIDER,
    getCapabilities: () => Effect.succeed(OpenCodeProviderCapabilitiesV2),
    planSelectionTransition: () => Effect.succeed(turnScopedSelectionTransition()),
    openSession: Effect.fn("OpenCodeAdapterV2.openSession")(
      function* (input: ProviderAdapter.ProviderAdapterV2OpenSessionInput) {
        const scope = yield* Effect.scope;
        const cwd = input.runtimePolicy.cwd ?? serverConfig.cwd;
        const connection = yield* runtime.connectToOpenCodeServer({
          binaryPath: options.settings.binaryPath,
          directory: cwd,
          serverUrl: options.settings.serverUrl,
          environment: options.environment,
        });
        const client = runtime.createOpenCodeSdkClient({
          baseUrl: connection.url,
          directory: cwd,
          ...(connection.external && options.settings.serverPassword
            ? { serverPassword: options.settings.serverPassword }
            : {}),
        });

        const mcpSession = McpProviderSession.readMcpProviderSession(input.threadId);
        const hasT3Mcp = mcpSession !== undefined && !connection.external;
        const orchestrationSystemPrompt = t3OrchestrationSystemPrompt(hasT3Mcp);
        if (hasT3Mcp) {
          yield* OpenCodeRuntime.runOpenCodeSdk("mcp.add", () =>
            client.mcp.add({
              name: "t3-code",
              config: {
                type: "remote",
                url: mcpSession.endpoint,
                headers: { Authorization: mcpSession.authorizationHeader },
                oauth: false,
              },
            }),
          );
        }

        const now = yield* DateTime.now;
        let sessionEntity: OrchestrationV2ProviderSession = {
          id: input.providerSessionId,
          driver: OPENCODE_PROVIDER,
          providerInstanceId: options.instanceId,
          status: "ready",
          cwd,
          model: input.modelSelection.model,
          capabilities: OpenCodeProviderCapabilitiesV2,
          createdAt: now,
          updatedAt: now,
          lastError: null,
        };
        const events = yield* Queue.unbounded<ProviderAdapter.ProviderAdapterV2Event, Cause.Done>();
        let nativeStreamFailure: OrchestrationV2ProviderFailure | null = null;
        const threads = new Map<string, OpenCodeThreadState>();
        const commandReceipts = new Map<string, Deferred.Deferred<void>>();
        const commandControllers = new Map<string, Set<AbortController>>();
        const pendingRequests = new Map<string, PendingOpenCodeRequest>();
        const pendingRequestsByNativeId = new Map<string, PendingOpenCodeRequest>();
        const subagentsByNativeItemId = new Map<string, OpenCodeSubagentContext>();
        const subagentsByChildSessionId = new Map<string, OpenCodeSubagentContext>();
        // Permission and question requests can originate from child sessions
        // (task subagents and their descendants). Related sessions map back
        // to the root thread state whose active turn owns the request; asks
        // arriving before the relation is known resolve it via session.get.
        const relatedSessionOwners = new Map<string, OpenCodeThreadState>();
        // Sessions of this runtime that OpenCode reports busy. A background
        // task child keeps running after its parent turn settles, so idle
        // release must not close the server under it.
        const busySessionIds = new Set<string>();
        // Requests settled before their session relation resolved: a late
        // routing attempt must never resurrect them. Bounded because entries
        // only matter for the seconds a routing retry can still be running.
        const settledNativeRequestIds = new Set<string>();
        const pendingChildRequestRoutes = new Set<string>();
        const rememberSettledRequest = (nativeRequestId: string) => {
          if (settledNativeRequestIds.size >= 2_048) settledNativeRequestIds.clear();
          settledNativeRequestIds.add(nativeRequestId);
        };
        const abortController = new AbortController();
        let closing = false;
        let hasConnected = false;

        const emitProviderEvent = (event: ProviderAdapter.ProviderAdapterV2Event) =>
          Queue.offer(events, event).pipe(Effect.asVoid);

        const logProtocolEvent = makeOpenCodeProtocolLogger({
          nativeEventLogger: options.nativeEventLogger,
          idAllocator,
          providerInstanceId: options.instanceId,
          providerSessionId: input.providerSessionId,
          threadId: input.threadId,
        });

        const sdkCall = <A>(
          method: string,
          payload: unknown,
          call: (signal: AbortSignal) => Promise<A>,
        ): Effect.Effect<A, OpenCodeRuntime.OpenCodeRuntimeError> =>
          logProtocolEvent({
            direction: "outgoing",
            messageKind: "request",
            method,
            payload,
          }).pipe(
            Effect.andThen(OpenCodeRuntime.runOpenCodeSdk(method, call)),
            Effect.tap((response) =>
              logProtocolEvent({
                direction: "incoming",
                messageKind: "response",
                method,
                payload: sdkResponseForRawLog(response),
              }),
            ),
          );

        const abortDescendants = (rootId: string) =>
          Effect.gen(function* () {
            const visited = new Set([rootId]);
            const semaphore = Semaphore.makeUnsafe(8);
            const visit = (
              sessionId: string,
              abort: boolean,
            ): Effect.Effect<OpenCodeRuntime.OpenCodeRuntimeError | undefined> =>
              Effect.gen(function* () {
                const abortResult = abort
                  ? yield* sdkCall("session.abort", { sessionID: sessionId }, (signal) =>
                      client.session.abort({ sessionID: sessionId }, { signal }),
                    ).pipe(
                      semaphore.withPermit,
                      Effect.catchIf(isOpenCodeNotFound, () => Effect.void),
                      Effect.result,
                    )
                  : undefined;
                const childrenResult = yield* sdkCall(
                  "session.children",
                  { sessionID: sessionId },
                  (signal) => client.session.children({ sessionID: sessionId }, { signal }),
                ).pipe(
                  semaphore.withPermit,
                  Effect.catchIf(isOpenCodeNotFound, () => Effect.void),
                  Effect.result,
                );
                const firstFailure =
                  abortResult?._tag === "Failure" ? abortResult.failure : undefined;
                if (childrenResult._tag === "Failure")
                  return firstFailure ?? childrenResult.failure;
                const fresh = (childrenResult.success?.data ?? []).filter((child) => {
                  if (visited.has(child.id)) return false;
                  visited.add(child.id);
                  return true;
                });
                const failures = yield* Effect.forEach(fresh, (child) => visit(child.id, true), {
                  concurrency: 8,
                });
                return firstFailure ?? failures.find((failure) => failure !== undefined);
              });
            const failure = yield* visit(rootId, false);
            if (failure) return yield* Effect.fail(failure);
          }).pipe(Effect.timeout("15 seconds"));

        const updateProviderSession = (
          status: OrchestrationV2ProviderSession["status"],
          lastError: string | null = sessionEntity.lastError,
        ) =>
          Effect.gen(function* () {
            const updatedAt = yield* DateTime.now;
            sessionEntity = { ...sessionEntity, status, lastError, updatedAt };
            yield* emitProviderEvent({
              type: "provider_session.updated",
              driver: OPENCODE_PROVIDER,
              providerSession: sessionEntity,
            });
          });

        const updateProviderThread = (
          state: OpenCodeThreadState,
          patch: Partial<OrchestrationV2ProviderThread>,
        ) =>
          Effect.gen(function* () {
            const updatedAt = yield* DateTime.now;
            state.providerThread = { ...state.providerThread, ...patch, updatedAt };
            yield* emitProviderEvent({
              type: "provider_thread.updated",
              driver: OPENCODE_PROVIDER,
              providerThread: state.providerThread,
            });
          });

        const itemOrdinal = (turn: ActiveOpenCodeTurn, nativeItemId: string): number => {
          const existing = turn.itemOrdinals.get(nativeItemId);
          if (existing !== undefined) return existing;
          const ordinal = turn.nextItemOrdinal++;
          turn.itemOrdinals.set(nativeItemId, ordinal);
          return ordinal;
        };

        const emitProviderTurn = (
          state: OpenCodeThreadState,
          turn: ActiveOpenCodeTurn,
          status: OrchestrationV2ProviderTurn["status"],
          completedAt: DateTime.Utc | null,
        ) => {
          const providerTurn: OrchestrationV2ProviderTurn = {
            ...turn.providerTurn,
            nativeTurnRef:
              turn.nativeUserMessageId === null
                ? turn.providerTurn.nativeTurnRef
                : providerRef(turn.nativeUserMessageId, "weak"),
            status,
            completedAt,
            ...(completedAt === null
              ? {}
              : {
                  turnTokenUsage:
                    turn.usage.partIds.size === 0
                      ? {
                          usageScope: "main_agent" as const,
                          usageStatus: "unavailable" as const,
                          hasSubagents: turn.usage.hasSubagents,
                        }
                      : {
                          usageScope: "main_agent" as const,
                          usageStatus:
                            status === "completed" &&
                            turn.usage.complete &&
                            turn.usage.unresolvedStepsByMessageId.size === 0
                              ? ("complete" as const)
                              : ("partial" as const),
                          inputTokens: turn.usage.inputTokens,
                          cachedInputTokens: turn.usage.cachedInputTokens,
                          cacheCreationTokens: turn.usage.cacheCreationTokens,
                          outputTokens: turn.usage.outputTokens,
                          reasoningTokens: turn.usage.reasoningTokens,
                          hasSubagents: turn.usage.hasSubagents,
                        },
                }),
          };
          Object.assign(turn.providerTurn, providerTurn);
          state.providerTurns.set(String(providerTurn.id), providerTurn);
          return emitProviderEvent({
            type: "provider_turn.updated",
            driver: OPENCODE_PROVIDER,
            threadId: turn.threadId,
            providerTurn,
          });
        };

        const emitTextPart = Effect.fnUntraced(function* (
          state: OpenCodeThreadState,
          turn: ActiveOpenCodeTurn,
          part: Extract<OpenCodePart, { type: "text" | "reasoning" }>,
          forceCompleted = false,
        ) {
          if (part.type === "text" && (part.ignored === true || part.synthetic === true)) return;
          if (part.text.length === 0) return;
          const emittedAt = yield* DateTime.now;
          const isCompleted = forceCompleted || part.time?.end !== undefined;
          const startedAt = dateTimeFromEpoch(part.time?.start, emittedAt);
          const completedAt = isCompleted ? dateTimeFromEpoch(part.time?.end, emittedAt) : null;
          const nativeItemRef = providerRef(part.id);
          const nodeId = idAllocator.derive.nodeFromProviderItem({
            driver: OPENCODE_PROVIDER,
            nativeItemId: part.id,
          });
          const turnItemId = idAllocator.derive.turnItemFromProviderItem({
            driver: OPENCODE_PROVIDER,
            nativeItemId: part.id,
          });
          const ordinal = itemOrdinal(turn, part.id);
          yield* emitProviderEvent({
            type: "node.updated",
            driver: OPENCODE_PROVIDER,
            node: {
              id: nodeId,
              threadId: turn.threadId,
              runId: turn.runId,
              parentNodeId: turn.rootNodeId,
              rootNodeId: turn.rootNodeId,
              kind: part.type === "text" ? "assistant_message" : "reasoning",
              status: isCompleted ? "completed" : "running",
              countsForRun: false,
              providerThreadId: state.providerThread.id,
              providerTurnId: turn.providerTurnId,
              nativeItemRef,
              runtimeRequestId: null,
              checkpointScopeId: null,
              startedAt,
              completedAt,
            },
          });
          if (part.type === "text") {
            const messageId = idAllocator.derive.messageFromProviderItem({
              driver: OPENCODE_PROVIDER,
              nativeItemId: part.id,
            });
            const message: OrchestrationV2ConversationMessage = {
              createdBy: "agent",
              creationSource: "provider",
              id: messageId,
              threadId: turn.threadId,
              runId: turn.runId,
              nodeId,
              role: "assistant",
              text: part.text,
              attachments: [],
              streaming: !isCompleted,
              createdAt: startedAt,
              updatedAt: emittedAt,
            };
            state.messages.set(String(message.id), message);
            yield* emitProviderEvent({
              type: "message.updated",
              driver: OPENCODE_PROVIDER,
              message,
            });
            yield* emitProviderEvent({
              type: "turn_item.updated",
              driver: OPENCODE_PROVIDER,
              turnItem: {
                id: turnItemId,
                threadId: turn.threadId,
                runId: turn.runId,
                nodeId,
                providerThreadId: state.providerThread.id,
                providerTurnId: turn.providerTurnId,
                nativeItemRef,
                parentItemId: null,
                ordinal,
                status: isCompleted ? "completed" : "running",
                title: null,
                startedAt,
                completedAt,
                updatedAt: emittedAt,
                type: "assistant_message",
                messageId,
                text: part.text,
                streaming: !isCompleted,
              },
            });
            return;
          }
          yield* emitProviderEvent({
            type: "turn_item.updated",
            driver: OPENCODE_PROVIDER,
            turnItem: {
              id: turnItemId,
              threadId: turn.threadId,
              runId: turn.runId,
              nodeId,
              providerThreadId: state.providerThread.id,
              providerTurnId: turn.providerTurnId,
              nativeItemRef,
              parentItemId: null,
              ordinal,
              status: isCompleted ? "completed" : "running",
              title: null,
              startedAt,
              completedAt,
              updatedAt: emittedAt,
              type: "reasoning",
              text: part.text,
              streaming: !isCompleted,
            },
          });
        });

        const emitSubagent = Effect.fnUntraced(function* (
          state: OpenCodeThreadState,
          turn: ActiveOpenCodeTurn,
          part: ToolPart,
        ) {
          const now = yield* DateTime.now;
          const nativeItemRef = providerRef(part.id);
          const nodeId = idAllocator.derive.nodeFromProviderItem({
            driver: OPENCODE_PROVIDER,
            nativeItemId: part.id,
          });
          const turnItemId = idAllocator.derive.turnItemFromProviderItem({
            driver: OPENCODE_PROVIDER,
            nativeItemId: part.id,
          });
          turn.usage.hasSubagents = true;
          const input = toolInput(part);
          const prompt = recordString(input, "prompt") ?? "";
          const title = toolTitle(part) ?? recordString(input, "description") ?? null;
          let context = subagentsByNativeItemId.get(part.id);
          if (context === undefined) {
            context = {
              nativeItemId: part.id,
              nodeId,
              parentState: state,
              parentTurn: turn,
              prompt,
              title,
              startedAt: toolStartedAt(part, now),
              childSessionId: null,
              childThreadId: null,
              childProviderThreadId: null,
              model: null,
              result: null,
            };
            subagentsByNativeItemId.set(part.id, context);
          }
          context.model = toolModel(part) ?? context.model;
          const childSessionId = taskSessionId(part);
          if (childSessionId !== null && context.childSessionId === null) {
            context.childSessionId = childSessionId;
            context.childThreadId = idAllocator.derive.threadFromProviderThread({
              driver: OPENCODE_PROVIDER,
              nativeThreadId: childSessionId,
            });
            context.childProviderThreadId = idAllocator.derive.providerThread({
              driver: OPENCODE_PROVIDER,
              nativeThreadId: childSessionId,
            });
            subagentsByChildSessionId.set(childSessionId, context);
            relatedSessionOwners.set(childSessionId, state);
            const childModelSelection: ModelSelection = {
              instanceId: options.instanceId,
              model: context.model ?? turn.modelSelection.model,
            };
            const childThread = makeSubagentChildThread({
              parentThread: turn.appThread,
              childThreadId: context.childThreadId,
              parentNodeId: nodeId,
              activeProviderThreadId: context.childProviderThreadId,
              providerInstanceId: options.instanceId,
              modelSelection: childModelSelection,
              title: subagentThreadTitle({
                parentTitle: turn.appThread.title,
                title,
                prompt,
                ordinal: itemOrdinal(turn, part.id),
              }),
              now,
              createdBy: "agent",
              creationSource: "provider",
            });
            const childProviderThread: OrchestrationV2ProviderThread = {
              id: context.childProviderThreadId,
              driver: OPENCODE_PROVIDER,
              providerInstanceId: options.instanceId,
              providerSessionId: inputProviderSessionId,
              appThreadId: context.childThreadId,
              ownerNodeId: nodeId,
              nativeThreadRef: providerRef(childSessionId),
              nativeConversationHeadRef: null,
              status: "active",
              firstRunOrdinal: null,
              lastRunOrdinal: null,
              handoffIds: [],
              forkedFrom: null,
              createdAt: now,
              updatedAt: now,
            };
            const childSessionResponse = yield* sdkCall(
              "session.get",
              { sessionID: childSessionId },
              () => client.session.get({ sessionID: childSessionId }),
            );
            const nativeChildSession = unwrapData("session.get", childSessionResponse);
            const childPermission = openCodeChildPermissionRules(
              turn.runtimePolicy,
              nativeChildSession.permission ?? [],
            );
            yield* sdkCall(
              "session.update",
              { sessionID: childSessionId, permission: childPermission },
              () =>
                client.session.update({
                  sessionID: childSessionId,
                  permission: childPermission,
                }),
            );
            threads.set(childSessionId, {
              nativeSessionId: childSessionId,
              providerThread: childProviderThread,
              appThread: childThread,
              activeTurn: null,
              providerTurns: new Map(),
              messages: new Map(),
              runtimeRequests: new Map(),
              messageRoles: new Map(),
              userMessageIds: [],
              parentSubagent: context,
              nextChildTurnOrdinal: 1,
              nextAdmissionGeneration: 1,
            });
            yield* emitProviderEvent({
              type: "app_thread.created",
              driver: OPENCODE_PROVIDER,
              appThread: childThread,
            });
            yield* emitProviderEvent({
              type: "provider_thread.updated",
              driver: OPENCODE_PROVIDER,
              providerThread: childProviderThread,
            });
          }
          const output = toolOutput(part);
          if (part.state.status === "completed" && output !== undefined) context.result = output;
          const status = toolStatus(part);
          const completedAt = toolCompletedAt(part, now);
          const subagentStatus: OrchestrationV2Subagent["status"] =
            status.item === "failed"
              ? "failed"
              : status.item === "completed"
                ? "completed"
                : status.item === "pending"
                  ? "pending"
                  : "running";
          const subagent: OrchestrationV2Subagent = {
            id: nodeId,
            threadId: turn.threadId,
            runId: turn.runId,
            parentNodeId: turn.rootNodeId,
            origin: "provider_native",
            createdBy: "agent",
            driver: OPENCODE_PROVIDER,
            providerInstanceId: options.instanceId,
            providerThreadId: context.childProviderThreadId,
            childThreadId: context.childThreadId,
            nativeTaskRef: nativeItemRef,
            prompt,
            title,
            model: context.model,
            status: subagentStatus,
            result: context.result,
            startedAt: context.startedAt,
            completedAt,
            updatedAt: now,
          };
          yield* emitProviderEvent({
            type: "node.updated",
            driver: OPENCODE_PROVIDER,
            node: {
              id: nodeId,
              threadId: turn.threadId,
              runId: turn.runId,
              parentNodeId: turn.rootNodeId,
              rootNodeId: turn.rootNodeId,
              kind: "subagent",
              status: status.node,
              countsForRun: false,
              providerThreadId: context.childProviderThreadId ?? state.providerThread.id,
              providerTurnId: turn.providerTurnId,
              nativeItemRef,
              runtimeRequestId: null,
              checkpointScopeId: null,
              startedAt: context.startedAt,
              completedAt,
            },
          });
          yield* emitProviderEvent({
            type: "subagent.updated",
            driver: OPENCODE_PROVIDER,
            subagent,
          });
          yield* emitProviderEvent({
            type: "turn_item.updated",
            driver: OPENCODE_PROVIDER,
            turnItem: {
              id: turnItemId,
              threadId: turn.threadId,
              runId: turn.runId,
              nodeId,
              providerThreadId: state.providerThread.id,
              providerTurnId: turn.providerTurnId,
              nativeItemRef,
              parentItemId: null,
              ordinal: itemOrdinal(turn, part.id),
              status: status.item,
              title,
              startedAt: context.startedAt,
              completedAt,
              updatedAt: now,
              type: "subagent",
              subagentId: nodeId,
              origin: "provider_native",
              driver: OPENCODE_PROVIDER,
              providerInstanceId: options.instanceId,
              childThreadId: context.childThreadId,
              prompt,
              result: context.result,
            },
          });
        });

        const emitToolPart = Effect.fnUntraced(function* (
          state: OpenCodeThreadState,
          turn: ActiveOpenCodeTurn,
          part: ToolPart,
        ) {
          const normalizedTool = part.tool.toLowerCase();
          if (normalizedTool === "task") {
            yield* emitSubagent(state, turn, part);
            return;
          }
          // question.asked carries the respondable semantic item. Projecting
          // the implementation tool as well would duplicate it in the UI.
          if (normalizedTool === "question") return;
          const now = yield* DateTime.now;
          const status = toolStatus(part);
          const startedAt = toolStartedAt(part, now);
          const completedAt = toolCompletedAt(part, now);
          const nativeItemRef = providerRef(part.id);
          const nodeId = idAllocator.derive.nodeFromProviderItem({
            driver: OPENCODE_PROVIDER,
            nativeItemId: part.id,
          });
          const turnItemId = idAllocator.derive.turnItemFromProviderItem({
            driver: OPENCODE_PROVIDER,
            nativeItemId: part.id,
          });
          const base = {
            id: turnItemId,
            threadId: turn.threadId,
            runId: turn.runId,
            nodeId,
            providerThreadId: state.providerThread.id,
            providerTurnId: turn.providerTurnId,
            nativeItemRef,
            parentItemId: null,
            ordinal: itemOrdinal(turn, part.id),
            status: status.item,
            title: toolTitle(part),
            startedAt,
            completedAt,
            updatedAt: now,
          } satisfies Pick<
            OrchestrationV2TurnItem,
            | "id"
            | "threadId"
            | "runId"
            | "nodeId"
            | "providerThreadId"
            | "providerTurnId"
            | "nativeItemRef"
            | "parentItemId"
            | "ordinal"
            | "status"
            | "title"
            | "startedAt"
            | "completedAt"
            | "updatedAt"
          >;
          const turnItem = openCodeToolTurnItem(base, {
            name: part.tool,
            input: toolInput(part),
            output: toolOutput(part),
            completedMetadata: part.state.status === "completed" ? part.state.metadata : undefined,
          });
          yield* emitProviderEvent({
            type: "node.updated",
            driver: OPENCODE_PROVIDER,
            node: {
              id: nodeId,
              threadId: turn.threadId,
              runId: turn.runId,
              parentNodeId: turn.rootNodeId,
              rootNodeId: turn.rootNodeId,
              kind: "tool_call",
              status: status.node,
              countsForRun: false,
              providerThreadId: state.providerThread.id,
              providerTurnId: turn.providerTurnId,
              nativeItemRef,
              runtimeRequestId: null,
              checkpointScopeId: null,
              startedAt,
              completedAt,
            },
          });
          yield* emitProviderEvent({
            type: "turn_item.updated",
            driver: OPENCODE_PROVIDER,
            turnItem,
          });
        });

        const emitTodo = Effect.fnUntraced(function* (
          state: OpenCodeThreadState,
          turn: ActiveOpenCodeTurn,
          todos: ReadonlyArray<OpenCodeTodo>,
        ) {
          const now = yield* DateTime.now;
          if (turn.planId === null) {
            turn.planId = yield* idAllocator.allocate.plan({
              threadId: turn.threadId,
              ...(turn.runId === null ? {} : { runId: turn.runId }),
              driver: OPENCODE_PROVIDER,
            });
          }
          const planId = turn.planId;
          const nativeItemId = `${state.nativeSessionId}:todo:${turn.providerTurnId}`;
          const nodeId = idAllocator.derive.nodeFromProviderItem({
            driver: OPENCODE_PROVIDER,
            nativeItemId,
          });
          const turnItemId = idAllocator.derive.turnItemFromProviderItem({
            driver: OPENCODE_PROVIDER,
            nativeItemId,
          });
          const steps: Array<OrchestrationV2PlanStep> = todos.map((todo, index) => ({
            id: `${nativeItemId}:${index + 1}`,
            text: todo.content.trim() || `Todo ${index + 1}`,
            status:
              todo.status === "completed"
                ? "completed"
                : todo.status === "in_progress"
                  ? "running"
                  : "pending",
          }));
          const completed = steps.length > 0 && steps.every((step) => step.status === "completed");
          yield* emitProviderEvent({
            type: "node.updated",
            driver: OPENCODE_PROVIDER,
            node: {
              id: nodeId,
              threadId: turn.threadId,
              runId: turn.runId,
              parentNodeId: turn.rootNodeId,
              rootNodeId: turn.rootNodeId,
              kind: "todo_list",
              status: completed ? "completed" : "running",
              countsForRun: false,
              providerThreadId: state.providerThread.id,
              providerTurnId: turn.providerTurnId,
              nativeItemRef: providerRef(nativeItemId, "weak"),
              runtimeRequestId: null,
              checkpointScopeId: null,
              startedAt: turn.startedAt,
              completedAt: completed ? now : null,
            },
          });
          yield* emitProviderEvent({
            type: "plan.updated",
            driver: OPENCODE_PROVIDER,
            plan: {
              id: planId,
              threadId: turn.threadId,
              runId: turn.runId,
              nodeId,
              status: completed ? "completed" : "active",
              kind: "todo_list",
              steps,
            },
          });
          yield* emitProviderEvent({
            type: "turn_item.updated",
            driver: OPENCODE_PROVIDER,
            turnItem: {
              id: turnItemId,
              threadId: turn.threadId,
              runId: turn.runId,
              nodeId,
              providerThreadId: state.providerThread.id,
              providerTurnId: turn.providerTurnId,
              nativeItemRef: providerRef(nativeItemId, "weak"),
              parentItemId: null,
              ordinal: itemOrdinal(turn, nativeItemId),
              status: completed ? "completed" : "running",
              title: "Todo list",
              startedAt: turn.startedAt,
              completedAt: completed ? now : null,
              updatedAt: now,
              type: "todo_list",
              planId,
              steps,
            },
          });
        });

        const requestQuestions = (request: QuestionRequest) =>
          request.questions.map((question, index) => ({
            id: OpenCodeRuntime.openCodeQuestionId(index, question),
            header: question.header.trim() || `Question ${index + 1}`,
            question: question.question.trim() || question.header.trim() || `Question ${index + 1}`,
            options: question.options.map((option) => ({
              label: option.label.trim() || "Option",
              description: option.description.trim() || option.label.trim() || "Option",
            })),
          }));

        const runtimeRequestTurnItem = (
          pending: PendingOpenCodeRequest,
          status: OrchestrationV2TurnItem["status"],
          completedAt: DateTime.Utc | null,
          updatedAt: DateTime.Utc,
        ): OrchestrationV2TurnItem => {
          const base = {
            id: pending.turnItemId,
            threadId: pending.turn.threadId,
            runId: pending.turn.runId,
            nodeId: pending.nodeId,
            providerThreadId: pending.state.providerThread.id,
            providerTurnId: pending.turn.providerTurnId,
            nativeItemRef: providerRef(pending.nativeRequestId),
            parentItemId: null,
            ordinal: itemOrdinal(pending.turn, pending.nativeRequestId),
            status,
            startedAt: pending.createdAt,
            completedAt,
            updatedAt,
          };
          if (pending.question !== undefined) {
            return {
              ...base,
              title: "User input",
              type: "user_input_request",
              requestId: pending.requestId,
              questions: requestQuestions(pending.question),
            };
          }
          const permission = pending.permission;
          if (permission === undefined) {
            throw protocolError(`OpenCode request ${pending.requestId} has no native payload`);
          }
          return {
            ...base,
            title: permission.permission,
            type: "approval_request",
            requestId: pending.requestId,
            requestKind: pending.requestKind === "user_input" ? "command" : pending.requestKind,
            prompt:
              permission.patterns.length === 0
                ? permission.permission
                : permission.patterns.join("\n"),
          };
        };

        const emitRuntimeRequest = Effect.fnUntraced(function* (
          owner: OpenCodeRequestOwner,
          nativeRequestId: string,
          request:
            | { readonly type: "permission"; readonly value: PermissionRequest }
            | { readonly type: "question"; readonly value: QuestionRequest },
        ) {
          if (pendingRequestsByNativeId.has(nativeRequestId)) return;
          const { state, turn, subagent } = owner;
          const now = yield* DateTime.now;
          const requestId = yield* idAllocator.allocate.runtimeRequest({
            driver: OPENCODE_PROVIDER,
            providerTurnId: turn.providerTurnId,
            nativeRequestId,
          });
          const nodeId = idAllocator.derive.approvalNode({ requestId });
          const turnItemId = idAllocator.derive.approvalTurnItem({ requestId });
          // The tool call belongs to the asking session's turn, not the owner's.
          const permissionToolName =
            request.type === "permission" && request.value.tool !== undefined
              ? threads
                  .get(request.value.sessionID)
                  ?.activeTurn?.toolNamesByCallId.get(request.value.tool.callID)
              : undefined;
          const permissionRequestKind =
            request.type === "permission"
              ? openCodePermissionRequestKind(request.value.permission, permissionToolName)
              : undefined;
          const requestKind: OrchestrationV2RuntimeRequest["kind"] =
            permissionRequestKind ?? "user_input";
          const pending: PendingOpenCodeRequest = {
            requestId,
            nativeRequestId,
            nativeSessionId: request.value.sessionID,
            turn,
            state,
            nodeId,
            parentNodeId: subagent?.nodeId ?? turn.rootNodeId,
            turnItemId,
            requestKind,
            createdAt: now,
            ...(request.type === "permission"
              ? { permission: request.value }
              : { question: request.value }),
          };
          pendingRequests.set(String(requestId), pending);
          pendingRequestsByNativeId.set(nativeRequestId, pending);
          const runtimeRequest: OrchestrationV2RuntimeRequest = {
            id: requestId,
            nodeId,
            providerTurnId: turn.providerTurnId,
            nativeRequestRef: providerRef(nativeRequestId),
            kind: requestKind,
            status: "pending",
            responseCapability: {
              type: "live",
              providerSessionId: inputProviderSessionId,
            },
            createdAt: now,
            resolvedAt: null,
          };
          state.runtimeRequests.set(String(requestId), runtimeRequest);
          yield* emitProviderEvent({
            type: "node.updated",
            driver: OPENCODE_PROVIDER,
            node: {
              id: nodeId,
              threadId: turn.threadId,
              runId: turn.runId,
              parentNodeId: pending.parentNodeId,
              rootNodeId: turn.rootNodeId,
              kind: request.type === "question" ? "user_input_request" : "approval_request",
              status: "waiting",
              countsForRun: false,
              providerThreadId: state.providerThread.id,
              providerTurnId: turn.providerTurnId,
              nativeItemRef: providerRef(nativeRequestId),
              runtimeRequestId: requestId,
              checkpointScopeId: null,
              startedAt: now,
              completedAt: null,
            },
          });
          yield* emitProviderEvent({
            type: "runtime_request.updated",
            driver: OPENCODE_PROVIDER,
            threadId: turn.threadId,
            runtimeRequest,
          });
          yield* emitProviderEvent({
            type: "turn_item.updated",
            driver: OPENCODE_PROVIDER,
            turnItem: runtimeRequestTurnItem(pending, "waiting", null, now),
          });
          yield* updateProviderSession("waiting", null);
        });

        const resolveRuntimeRequest = Effect.fnUntraced(function* (
          nativeRequestId: string,
          status: "resolved" | "cancelled",
        ) {
          const pending = pendingRequestsByNativeId.get(nativeRequestId);
          if (pending === undefined) return;
          const now = yield* DateTime.now;
          const current = pending.state.runtimeRequests.get(String(pending.requestId));
          if (current !== undefined) {
            const resolved: OrchestrationV2RuntimeRequest = {
              ...current,
              status,
              resolvedAt: now,
            };
            pending.state.runtimeRequests.set(String(pending.requestId), resolved);
            yield* emitProviderEvent({
              type: "runtime_request.updated",
              driver: OPENCODE_PROVIDER,
              threadId: pending.turn.threadId,
              runtimeRequest: resolved,
            });
          }
          yield* emitProviderEvent({
            type: "node.updated",
            driver: OPENCODE_PROVIDER,
            node: {
              id: pending.nodeId,
              threadId: pending.turn.threadId,
              runId: pending.turn.runId,
              parentNodeId: pending.parentNodeId,
              rootNodeId: pending.turn.rootNodeId,
              kind: pending.question === undefined ? "approval_request" : "user_input_request",
              status: status === "resolved" ? "completed" : "cancelled",
              countsForRun: false,
              providerThreadId: pending.state.providerThread.id,
              providerTurnId: pending.turn.providerTurnId,
              nativeItemRef: providerRef(nativeRequestId),
              runtimeRequestId: pending.requestId,
              checkpointScopeId: null,
              startedAt: pending.createdAt,
              completedAt: now,
            },
          });
          yield* emitProviderEvent({
            type: "turn_item.updated",
            driver: OPENCODE_PROVIDER,
            turnItem: runtimeRequestTurnItem(
              pending,
              status === "resolved" ? "completed" : "cancelled",
              now,
              now,
            ),
          });
          pendingRequests.delete(String(pending.requestId));
          pendingRequestsByNativeId.delete(nativeRequestId);
          const hasOtherPending = Array.from(pendingRequests.values()).some(
            (candidate) => candidate.turn.isRoot,
          );
          if (!hasOtherPending) yield* updateProviderSession("running", null);
        });

        /** Resolve the thread state a session belongs to: its own, or for a
         *  child not registered yet, the nearest known ancestor found by walking
         *  the native parent chain. Registers every hop so later requests from
         *  the same child resolve without another lookup. */
        const resolveSessionOwner = Effect.fnUntraced(function* (sessionId: string) {
          const known = threads.get(sessionId) ?? relatedSessionOwners.get(sessionId);
          if (known !== undefined) return known;
          let cursor = sessionId;
          const hops: string[] = [];
          for (let depth = 0; depth < 5; depth += 1) {
            const response = yield* sdkCall("session.get", { sessionID: cursor }, () =>
              client.session.get({ sessionID: cursor }),
            ).pipe(Effect.option);
            const info = Option.getOrUndefined(response)?.data;
            const parentId = info?.parentID;
            if (parentId === undefined) return undefined;
            hops.push(cursor);
            const owner = threads.get(parentId) ?? relatedSessionOwners.get(parentId);
            if (owner !== undefined) {
              for (const hop of hops) relatedSessionOwners.set(hop, owner);
              return owner;
            }
            cursor = parentId;
          }
          return undefined;
        });

        /** Every request is asked on the top-level thread and its active turn,
         *  under the subagent that leads to the asking session, because native
         *  subagent threads are hidden from the sidebar. A child's request can
         *  arrive before the task part or session.created event that reveals
         *  its relation to a thread. The first resolution attempt runs inline
         *  (the replayable path); if the relation or the owning turn is not
         *  established yet, a short forked backoff keeps trying instead of
         *  dropping the request. */
        const routeRuntimeRequest = Effect.fnUntraced(function* (
          nativeRequestId: string,
          sessionId: string,
          request:
            | { readonly type: "permission"; readonly value: PermissionRequest }
            | { readonly type: "question"; readonly value: QuestionRequest },
        ) {
          if (pendingChildRequestRoutes.has(nativeRequestId)) return;
          const attempt = Effect.gen(function* () {
            if (
              settledNativeRequestIds.has(nativeRequestId) ||
              pendingRequestsByNativeId.has(nativeRequestId)
            ) {
              return true;
            }
            const state = yield* resolveSessionOwner(sessionId);
            const owner = state === undefined ? undefined : topLevelRequestOwner(state);
            if (owner === undefined) return false;
            yield* emitRuntimeRequest(owner, nativeRequestId, request);
            return true;
          });
          if (yield* attempt) return;
          pendingChildRequestRoutes.add(nativeRequestId);
          yield* Effect.gen(function* () {
            for (let retry = 0; retry < 5; retry += 1) {
              yield* Effect.sleep(Duration.millis(Math.min(200 * 2 ** retry, 2_000)));
              if (yield* attempt) return;
            }
          }).pipe(
            Effect.ensuring(Effect.sync(() => pendingChildRequestRoutes.delete(nativeRequestId))),
            Effect.forkIn(scope),
          );
        });

        const finalizeTurn = Effect.fnUntraced(function* (
          state: OpenCodeThreadState,
          turn: ActiveOpenCodeTurn,
          status: TerminalTurnStatus,
          terminal?: {
            readonly failure?: OrchestrationV2ProviderFailure;
            readonly threadDisposition?: "reusable" | "broken";
          },
        ) {
          if (turn.finalized) return;
          if (nativeStreamFailure !== null) {
            status = "failed";
            terminal = { failure: nativeStreamFailure, threadDisposition: "broken" };
          }
          turn.finalized = true;
          const completedAt = yield* DateTime.now;
          for (const part of turn.parts.values()) {
            if (part.type === "text" || part.type === "reasoning") {
              yield* emitTextPart(state, turn, part, true);
            }
          }
          for (const pending of Array.from(pendingRequests.values())) {
            if (
              pending.turn.providerTurnId === turn.providerTurnId ||
              pending.nativeSessionId === state.nativeSessionId
            ) {
              yield* resolveRuntimeRequest(pending.nativeRequestId, "cancelled");
            }
          }
          yield* emitProviderTurn(state, turn, status, completedAt);
          const threadDisposition = terminal?.threadDisposition ?? "reusable";
          yield* updateProviderThread(state, {
            status: turn.isRoot ? "active" : threadDisposition === "broken" ? "error" : "idle",
            nativeConversationHeadRef:
              turn.nativeUserMessageId === null
                ? state.providerThread.nativeConversationHeadRef
                : providerRef(turn.nativeUserMessageId, "weak"),
          });
          state.activeTurn = null;
          if (!turn.isRoot) {
            yield* emitProviderEvent({
              type: "node.updated",
              driver: OPENCODE_PROVIDER,
              node: {
                id: turn.rootNodeId,
                threadId: turn.threadId,
                runId: null,
                parentNodeId: null,
                rootNodeId: turn.rootNodeId,
                kind: "root_turn",
                status,
                countsForRun: false,
                providerThreadId: state.providerThread.id,
                providerTurnId: turn.providerTurnId,
                nativeItemRef: providerRef(state.nativeSessionId),
                runtimeRequestId: null,
                checkpointScopeId: null,
                startedAt: turn.startedAt,
                completedAt,
              },
            });
            return;
          }
          const anotherTurnIsActive = Array.from(threads.values()).some(
            (candidate) => candidate.activeTurn?.isRoot === true,
          );
          yield* updateProviderSession(
            anotherTurnIsActive ? "running" : status === "failed" ? "error" : "ready",
            status === "failed" ? sessionEntity.lastError : null,
          );
          yield* emitProviderEvent(
            status === "failed"
              ? {
                  type: "turn.terminal",
                  driver: OPENCODE_PROVIDER,
                  providerThreadId: state.providerThread.id,
                  providerTurnId: turn.providerTurnId,
                  runOrdinal: turn.runOrdinal,
                  failureItemOrdinal: itemOrdinal(turn, `terminal-failure:${turn.providerTurnId}`),
                  status,
                  failure:
                    terminal?.failure ??
                    makeProviderFailure({
                      message: sessionEntity.lastError ?? undefined,
                      class: "provider_error",
                    }),
                  threadDisposition,
                }
              : {
                  type: "turn.terminal",
                  driver: OPENCODE_PROVIDER,
                  providerThreadId: state.providerThread.id,
                  providerTurnId: turn.providerTurnId,
                  runOrdinal: turn.runOrdinal,
                  status,
                  failure: null,
                  threadDisposition,
                },
          );
        });

        const promptAdmissionIsCurrent = (
          state: OpenCodeThreadState,
          turn: ActiveOpenCodeTurn,
          generation: number,
        ) =>
          state.activeTurn === turn &&
          !turn.finalized &&
          !turn.interrupted &&
          turn.admissionPending &&
          turn.admissionGeneration === generation;

        const runPromptAdmissionReconciliation = Effect.fnUntraced(function* (
          state: OpenCodeThreadState,
          turn: ActiveOpenCodeTurn,
          generation: number,
        ) {
          while (promptAdmissionIsCurrent(state, turn, generation)) {
            const status = yield* reconcileOpenCodePromptAdmissionStatus(
              turn,
              generation,
              sdkCall("session.status", { sessionID: state.nativeSessionId, generation }, () =>
                client.session.status(),
              ).pipe(
                Effect.match({
                  onFailure: () => "unknown" as const,
                  onSuccess: (response) => {
                    const statuses = unwrapData("session.status", response);
                    const sessionStatus = statuses[state.nativeSessionId];
                    return sessionStatus === undefined || sessionStatus.type === "idle"
                      ? ("idle" as const)
                      : ("busy" as const);
                  },
                }),
              ),
            );
            if (
              state.activeTurn !== turn ||
              status === "stale" ||
              turn.finalized ||
              turn.interrupted ||
              turn.admissionGeneration !== generation
            ) {
              return;
            }
            if (status === "idle") {
              yield* finalizeTurn(state, turn, "completed");
              return;
            }
            if (status === "busy") return;
            yield* Effect.sleep("250 millis");
          }
        });

        const reconcilePromptAdmission = Effect.fnUntraced(function* (
          state: OpenCodeThreadState,
          turn: ActiveOpenCodeTurn,
        ) {
          const generation = turn.admissionGeneration;
          if (
            !promptAdmissionIsCurrent(state, turn, generation) ||
            turn.admissionReconciliationGeneration === generation
          ) {
            return;
          }
          turn.admissionReconciliationGeneration = generation;
          yield* runPromptAdmissionReconciliation(state, turn, generation).pipe(
            Effect.ensuring(
              Effect.sync(() => {
                if (turn.admissionReconciliationGeneration === generation) {
                  turn.admissionReconciliationGeneration = null;
                }
              }),
            ),
            Effect.forkIn(scope),
          );
        });

        const createChildTurn = Effect.fnUntraced(function* (
          state: OpenCodeThreadState,
          message: Extract<OpenCodeMessage, { role: "user" }>,
        ) {
          if (state.appThread === null || state.parentSubagent === null) return null;
          const now = yield* DateTime.now;
          const startedAt = dateTimeFromEpoch(message.time.created, now);
          const rootNodeId = idAllocator.derive.nodeFromProviderItem({
            driver: OPENCODE_PROVIDER,
            nativeItemId: `${state.nativeSessionId}:root:${message.id}`,
          });
          const providerTurnId = idAllocator.derive.providerTurn({
            driver: OPENCODE_PROVIDER,
            nativeTurnId: message.id,
          });
          const providerTurn: OrchestrationV2ProviderTurn = {
            id: providerTurnId,
            providerThreadId: state.providerThread.id,
            nodeId: rootNodeId,
            runAttemptId: null,
            nativeTurnRef: providerRef(message.id, "weak"),
            ordinal: state.nextChildTurnOrdinal++,
            status: "running",
            startedAt,
            completedAt: null,
          };
          const turn: ActiveOpenCodeTurn = {
            isRoot: false,
            threadId: state.appThread.id,
            runId: null,
            rootNodeId,
            appThread: state.appThread,
            modelSelection: state.appThread.modelSelection,
            runtimePolicy: state.parentSubagent.parentTurn.runtimePolicy,
            providerTurnId,
            providerTurnOrdinal: providerTurn.ordinal,
            runOrdinal: state.parentSubagent.parentTurn.runOrdinal,
            runAttemptId: null,
            startedAt,
            itemOrdinals: new Map(),
            usage: makeOpenCodeTurnTokenUsageAccumulator(),
            parts: new Map(),
            partIdsByMessage: new Map(),
            toolNamesByCallId: new Map(),
            providerTurn,
            nextItemOrdinal: 1,
            nativeUserMessageId: message.id,
            admissionMessageId: null,
            interrupted: false,
            finalized: false,
            planId: null,
            admissionGeneration: 0,
            admissionReconciliationGeneration: null,
            admissionPending: false,
            admissionAccepted: true,
            admissionMessageObserved: true,
            idleDuringAdmission: false,
            admissionSettled: Deferred.makeUnsafe<void>(),
            admissionAbortController: null,
          };
          state.activeTurn = turn;
          state.providerTurns.set(String(providerTurnId), providerTurn);
          yield* emitProviderEvent({
            type: "node.updated",
            driver: OPENCODE_PROVIDER,
            node: {
              id: rootNodeId,
              threadId: turn.threadId,
              runId: null,
              parentNodeId: null,
              rootNodeId,
              kind: "root_turn",
              status: "running",
              countsForRun: false,
              providerThreadId: state.providerThread.id,
              providerTurnId,
              nativeItemRef: providerRef(message.id, "weak"),
              runtimeRequestId: null,
              checkpointScopeId: null,
              startedAt,
              completedAt: null,
            },
          });
          yield* emitProviderTurn(state, turn, "running", null);
          return turn;
        });

        const projectChildUserPart = Effect.fnUntraced(function* (
          state: OpenCodeThreadState,
          turn: ActiveOpenCodeTurn,
          part: Extract<OpenCodePart, { type: "text" }>,
        ) {
          const now = yield* DateTime.now;
          const messageId = idAllocator.derive.messageFromProviderItem({
            driver: OPENCODE_PROVIDER,
            nativeItemId: part.messageID,
          });
          const turnItemId = idAllocator.derive.turnItemFromProviderItem({
            driver: OPENCODE_PROVIDER,
            nativeItemId: part.messageID,
          });
          const projected: OrchestrationV2ConversationMessage = {
            createdBy: "agent",
            creationSource: "provider",
            id: messageId,
            threadId: turn.threadId,
            runId: null,
            nodeId: turn.rootNodeId,
            role: "user",
            text: part.text,
            attachments: [],
            streaming: false,
            createdAt: turn.startedAt,
            updatedAt: now,
          };
          state.messages.set(String(messageId), projected);
          yield* emitProviderEvent({
            type: "message.updated",
            driver: OPENCODE_PROVIDER,
            message: projected,
          });
          yield* emitProviderEvent({
            type: "turn_item.updated",
            driver: OPENCODE_PROVIDER,
            turnItem: {
              createdBy: "agent",
              creationSource: "provider",
              id: turnItemId,
              threadId: turn.threadId,
              runId: null,
              nodeId: turn.rootNodeId,
              providerThreadId: state.providerThread.id,
              providerTurnId: turn.providerTurnId,
              nativeItemRef: providerRef(part.messageID),
              parentItemId: null,
              ordinal: itemOrdinal(turn, part.messageID),
              status: "completed",
              title: null,
              startedAt: projected.createdAt,
              completedAt: now,
              updatedAt: now,
              type: "user_message",
              messageId,
              inputIntent: "turn_start",
              text: part.text,
              attachments: [],
            },
          });
        });

        const emitCompactionItem = Effect.fn("OpenCodeAdapterV2.emitCompactionItem")(function* (
          state: OpenCodeThreadState,
          turn: ActiveOpenCodeTurn,
        ) {
          const nativeItemId = `${turn.providerTurnId}:compaction`;
          if (turn.itemOrdinals.has(nativeItemId)) return;
          const now = yield* DateTime.now;
          yield* emitProviderEvent({
            type: "turn_item.updated",
            driver: OPENCODE_PROVIDER,
            turnItem: {
              id: idAllocator.derive.turnItemFromProviderItem({
                driver: OPENCODE_PROVIDER,
                nativeItemId,
              }),
              threadId: turn.threadId,
              runId: turn.runId,
              nodeId: turn.rootNodeId,
              providerThreadId: state.providerThread.id,
              providerTurnId: turn.providerTurnId,
              nativeItemRef: providerRef(nativeItemId, "weak"),
              parentItemId: null,
              ordinal: itemOrdinal(turn, nativeItemId),
              type: "compaction",
              driver: OPENCODE_PROVIDER,
              status: "completed",
              title: "Context compacted",
              startedAt: turn.startedAt,
              completedAt: now,
              updatedAt: now,
            },
          });
        });

        const handleMessageUpdated = Effect.fnUntraced(function* (
          event: Extract<OpenCodeEvent, { type: "message.updated" }>,
        ) {
          const state = threads.get(event.properties.sessionID);
          if (state === undefined) return;
          const message = event.properties.info;
          state.messageRoles.set(message.id, message.role);
          if (message.role === "assistant") {
            const usage = state.activeTurn?.usage;
            if (usage === undefined) return;
            const prior = usage.assistantOwnershipByMessageId.get(message.id);
            const ownership =
              prior !== undefined && prior !== "unknown"
                ? prior
                : !message.parentID
                  ? "unknown"
                  : usage.promptMessageIds.has(message.parentID)
                    ? "owned"
                    : "other";
            usage.assistantOwnershipByMessageId.set(message.id, ownership);
            if (ownership !== "unknown") {
              if (ownership === "owned") {
                for (const step of usage.unresolvedStepsByMessageId.get(message.id)?.values() ??
                  []) {
                  accumulateOpenCodeStepUsage(usage, step);
                }
              }
              usage.unresolvedStepsByMessageId.delete(message.id);
            }
            return;
          }
          const commandReceipt = commandReceipts.get(message.id);
          if (commandReceipt) yield* Deferred.succeed(commandReceipt, undefined);
          const isNewUserMessage = !state.userMessageIds.includes(message.id);
          if (isNewUserMessage) state.userMessageIds.push(message.id);
          let turn = state.activeTurn;
          if (turn === null && state.parentSubagent !== null && isNewUserMessage) {
            turn = yield* createChildTurn(state, message);
          }
          const matchesAdmission =
            turn !== null &&
            (turn.admissionMessageId === null || turn.admissionMessageId === message.id);
          if (turn !== null && matchesAdmission) turn.usage.promptMessageIds.add(message.id);
          if (turn !== null && matchesAdmission && turn.nativeUserMessageId === null) {
            turn.nativeUserMessageId = message.id;
            yield* emitProviderTurn(state, turn, "running", null);
          }
          if (turn !== null && matchesAdmission && turn.admissionPending) {
            if (advanceOpenCodePromptAdmission(turn, "user-message") === "reconcile-idle") {
              yield* reconcilePromptAdmission(state, turn);
            }
          }
        });

        const handlePartUpdated = Effect.fnUntraced(function* (
          event: Extract<OpenCodeEvent, { type: "message.part.updated" }>,
        ) {
          const part = event.properties.part;
          const state = threads.get(part.sessionID);
          const turn = state?.activeTurn;
          if (state === undefined || turn === null || turn === undefined || turn.finalized) return;
          if (part.type === "text" && state.messageRoles.get(part.messageID) === "user") {
            if (!turn.isRoot) yield* projectChildUserPart(state, turn, part);
            return;
          }
          if (part.type === "step-finish") {
            const usage = turn.usage;
            const ownership = usage.assistantOwnershipByMessageId.get(part.messageID);
            if (ownership === "owned") accumulateOpenCodeStepUsage(usage, part);
            else if (
              ownership === "unknown" ||
              (ownership === undefined && !state.messageRoles.has(part.messageID))
            ) {
              const steps =
                usage.unresolvedStepsByMessageId.get(part.messageID) ??
                new Map<string, OpenCodeStepUsage>();
              steps.set(part.id, { id: part.id, tokens: part.tokens });
              usage.unresolvedStepsByMessageId.set(part.messageID, steps);
            }
            return;
          }
          if (part.type === "tool") {
            // Approval routing needs the tool name, without retaining its input and output.
            turn.toolNamesByCallId.set(part.callID, part.tool);
          } else {
            turn.parts.set(part.id, part);
            const ids = turn.partIdsByMessage.get(part.messageID) ?? new Set<string>();
            ids.add(part.id);
            turn.partIdsByMessage.set(part.messageID, ids);
          }
          switch (part.type) {
            case "text":
            case "reasoning":
              yield* emitTextPart(state, turn, part);
              return;
            case "tool":
              yield* emitToolPart(state, turn, part);
              return;
            default:
              return;
          }
        });

        const handlePartDelta = Effect.fnUntraced(function* (
          event: Extract<OpenCodeEvent, { type: "message.part.delta" }>,
        ) {
          if (event.properties.field !== "text") return;
          const state = threads.get(event.properties.sessionID);
          const turn = state?.activeTurn;
          const current = turn?.parts.get(event.properties.partID);
          if (
            state === undefined ||
            turn === null ||
            turn === undefined ||
            current === undefined ||
            (current.type !== "text" && current.type !== "reasoning")
          ) {
            return;
          }
          const updated = { ...current, text: current.text + event.properties.delta };
          turn.parts.set(updated.id, updated);
          yield* emitTextPart(state, turn, updated);
        });

        const handleAssistantCompleted = Effect.fnUntraced(function* (
          event: Extract<OpenCodeEvent, { type: "message.updated" }>,
        ) {
          const message = event.properties.info;
          if (message.role !== "assistant" || message.time.completed === undefined) return;
          const state = threads.get(message.sessionID);
          const turn = state?.activeTurn;
          if (state === undefined || turn === null || turn === undefined) return;
          // Some OpenCode versions ignore the client-provided message ID. A
          // completed assistant message is definitive admission evidence, so
          // let the following idle event settle the turn without weakening
          // the stale-user-message guard.
          advanceOpenCodePromptAdmission(turn, "assistant-completed");
          for (const partId of turn.partIdsByMessage.get(message.id) ?? []) {
            const part = turn.parts.get(partId);
            if (part?.type === "text" || part?.type === "reasoning") {
              yield* emitTextPart(state, turn, part, true);
            }
          }
        });

        const handleEvent = Effect.fnUntraced(function* (event: OpenCodeEvent) {
          yield* logProtocolEvent({
            direction: "incoming",
            messageKind: "notification",
            method: event.type,
            payload: event,
          });
          switch (event.type) {
            case "server.connected":
              if (hasConnected) {
                for (const state of threads.values()) {
                  if (state.activeTurn !== null) state.activeTurn.usage.complete = false;
                }
              }
              hasConnected = true;
              return;
            case "message.updated":
              yield* handleMessageUpdated(event);
              yield* handleAssistantCompleted(event);
              return;
            case "session.compacted": {
              const state = threads.get(event.properties.sessionID);
              if (state?.activeTurn !== undefined && state.activeTurn !== null) {
                yield* emitCompactionItem(state, state.activeTurn);
              }
              return;
            }
            case "message.part.updated":
              yield* handlePartUpdated(event);
              return;
            case "message.part.delta":
              yield* handlePartDelta(event);
              return;
            case "todo.updated": {
              const state = threads.get(event.properties.sessionID);
              if (state?.activeTurn !== null && state?.activeTurn !== undefined) {
                yield* emitTodo(state, state.activeTurn, event.properties.todos);
              }
              return;
            }
            case "permission.asked":
              yield* routeRuntimeRequest(event.properties.id, event.properties.sessionID, {
                type: "permission",
                value: event.properties,
              });
              return;
            case "question.asked":
              yield* routeRuntimeRequest(event.properties.id, event.properties.sessionID, {
                type: "question",
                value: event.properties,
              });
              return;
            case "permission.replied":
            case "question.replied":
              rememberSettledRequest(event.properties.requestID);
              yield* resolveRuntimeRequest(event.properties.requestID, "resolved");
              return;
            case "question.rejected":
              rememberSettledRequest(event.properties.requestID);
              yield* resolveRuntimeRequest(event.properties.requestID, "cancelled");
              return;
            case "session.created":
            case "session.updated": {
              const info = event.properties.info;
              if (info.parentID !== undefined && !threads.has(info.id)) {
                const owner = threads.get(info.parentID) ?? relatedSessionOwners.get(info.parentID);
                if (owner !== undefined) {
                  relatedSessionOwners.set(info.id, owner);
                }
              }
              return;
            }
            case "session.deleted":
              relatedSessionOwners.delete(event.properties.info.id);
              busySessionIds.delete(event.properties.info.id);
              return;
            case "session.status": {
              const sessionId = event.properties.sessionID;
              switch (event.properties.status.type) {
                case "busy":
                case "retry":
                  if (threads.has(sessionId) || relatedSessionOwners.has(sessionId)) {
                    busySessionIds.add(sessionId);
                  }
                  break;
                case "idle":
                  busySessionIds.delete(sessionId);
                  break;
              }
              const state = threads.get(sessionId);
              if (state === undefined) return;
              if (event.properties.status.type === "busy") {
                yield* updateProviderThread(state, { status: "active" });
                return;
              }
              if (event.properties.status.type === "idle" && state.activeTurn !== null) {
                if (state.activeTurn.admissionPending) {
                  advanceOpenCodePromptAdmission(state.activeTurn, "idle");
                  return;
                }
                yield* finalizeTurn(
                  state,
                  state.activeTurn,
                  state.activeTurn.interrupted ? "interrupted" : "completed",
                );
              }
              return;
            }
            case "session.idle": {
              busySessionIds.delete(event.properties.sessionID);
              const state = threads.get(event.properties.sessionID);
              if (state?.activeTurn !== null && state?.activeTurn !== undefined) {
                if (state.activeTurn.admissionPending) {
                  advanceOpenCodePromptAdmission(state.activeTurn, "idle");
                  return;
                }
                yield* finalizeTurn(
                  state,
                  state.activeTurn,
                  state.activeTurn.interrupted ? "interrupted" : "completed",
                );
              }
              return;
            }
            case "session.error": {
              const states =
                event.properties.sessionID === undefined
                  ? Array.from(threads.values()).filter((state) => state.activeTurn !== null)
                  : [threads.get(event.properties.sessionID)].filter(
                      (state): state is OpenCodeThreadState => state !== undefined,
                    );
              const message = openCodeErrorMessage(event);
              if (
                !isMessageAbortedError(event) &&
                (event.properties.sessionID === undefined ||
                  states.some((state) => state.parentSubagent === null))
              ) {
                yield* updateProviderSession("error", message);
              }
              for (const state of states) {
                if (state.activeTurn !== null) {
                  yield* finalizeTurn(
                    state,
                    state.activeTurn,
                    terminalStatusForError(event, state.activeTurn),
                    {
                      failure: makeProviderFailure({
                        message,
                        code: event.properties.error?.name ?? null,
                        class: "provider_error",
                      }),
                      threadDisposition:
                        event.properties.sessionID === undefined ? "broken" : "reusable",
                    },
                  );
                }
              }
              return;
            }
            default:
              return;
          }
        });

        const inputProviderSessionId = input.providerSessionId;

        const subscription = yield* sdkCall("event.subscribe", {}, () =>
          client.event.subscribe(undefined, { signal: abortController.signal }),
        );
        yield* Scope.addFinalizer(
          scope,
          Effect.sync(() => abortController.abort()),
        );
        yield* Stream.fromAsyncIterable(
          subscription.stream,
          (cause) =>
            new OpenCodeRuntime.OpenCodeRuntimeError({
              operation: "event.subscribe",
              detail: OpenCodeRuntime.openCodeRuntimeErrorDetail(cause),
              cause,
            }),
        ).pipe(
          Stream.runForEach(handleEvent),
          Effect.exit,
          Effect.flatMap((exit) =>
            Effect.gen(function* () {
              // No further status can clear a busy session once the stream ends.
              busySessionIds.clear();
              if (closing || abortController.signal.aborted) return;
              const detail = Exit.isSuccess(exit)
                ? "OpenCode event stream ended unexpectedly."
                : OpenCodeRuntime.openCodeRuntimeErrorDetail(Cause.squash(exit.cause));
              nativeStreamFailure = makeProviderFailure({
                message: detail,
                class: "transport_error",
              });
              yield* updateProviderSession("error", detail);
              for (const state of threads.values()) {
                if (state.activeTurn !== null)
                  yield* finalizeTurn(state, state.activeTurn, "failed", {
                    failure: makeProviderFailure({ message: detail, class: "transport_error" }),
                    threadDisposition: "broken",
                  });
              }
              yield* Queue.end(events);
            }),
          ),
          Effect.forkIn(scope),
        );

        if (!connection.external && connection.exitCode !== null) {
          yield* connection.exitCode.pipe(
            Effect.flatMap((code) =>
              abortController.signal.aborted
                ? Effect.void
                : Effect.gen(function* () {
                    const detail = `OpenCode server exited unexpectedly (${code}).`;
                    yield* updateProviderSession("error", detail);
                    for (const state of threads.values()) {
                      if (state.activeTurn !== null) {
                        yield* finalizeTurn(state, state.activeTurn, "failed", {
                          failure: makeProviderFailure({
                            message: detail,
                            class: "transport_error",
                          }),
                          threadDisposition: "broken",
                        });
                      }
                    }
                  }),
            ),
            Effect.forkIn(scope),
          );
        }

        if (connection.external) {
          yield* Scope.addFinalizer(
            scope,
            Effect.suspend(() =>
              Effect.forEach(
                Array.from(threads.values()).filter((state) => state.parentSubagent === null),
                (state) =>
                  sdkCall("session.abort", { sessionID: state.nativeSessionId }, (signal) =>
                    client.session.abort({ sessionID: state.nativeSessionId }, { signal }),
                  ).pipe(
                    Effect.timeout("1 second"),
                    Effect.ignore({ log: true }),
                    Effect.andThen(
                      abortDescendants(state.nativeSessionId).pipe(
                        Effect.timeout("1 second"),
                        Effect.ignore({ log: true }),
                      ),
                    ),
                  ),
                { concurrency: 8, discard: true },
              ),
            ),
          );
        }

        yield* Scope.addFinalizer(
          scope,
          Effect.sync(() => {
            closing = true;
          }),
        );

        const registerThread = (
          nativeSession: OpenCodeSession,
          providerThread: OrchestrationV2ProviderThread,
          appThread: OrchestrationV2AppThread | null,
        ): OpenCodeThreadState => {
          const existing = threads.get(nativeSession.id);
          if (existing !== undefined) {
            existing.providerThread = providerThread;
            if (appThread !== null) existing.appThread = appThread;
            return existing;
          }
          const state: OpenCodeThreadState = {
            nativeSessionId: nativeSession.id,
            providerThread,
            appThread,
            activeTurn: null,
            providerTurns: new Map(),
            messages: new Map(),
            runtimeRequests: new Map(),
            messageRoles: new Map(),
            userMessageIds: [],
            parentSubagent: subagentsByChildSessionId.get(nativeSession.id) ?? null,
            nextChildTurnOrdinal: 1,
            nextAdmissionGeneration: 1,
          };
          threads.set(nativeSession.id, state);
          return state;
        };

        const resolvePromptParts = (turnInput: ProviderAdapter.ProviderAdapterV2TurnInput) => {
          const text = providerMessageTextWithAttachmentPaths({
            text: turnInput.message.text,
            attachments: turnInput.message.attachments,
            attachmentsDir: serverConfig.attachmentsDir,
          }).trim();
          const files = OpenCodeRuntime.toOpenCodeFileParts({
            attachments: turnInput.message.attachments,
            resolveAttachmentPath: (attachment) =>
              resolveAttachmentPath({ attachmentsDir: serverConfig.attachmentsDir, attachment }),
          });
          if (text.length === 0 && files.length === 0) {
            throw protocolError("OpenCode turns require text or at least one valid attachment");
          }
          return [...(text.length === 0 ? [] : [{ type: "text" as const, text }]), ...files];
        };

        const readSnapshot = Effect.fnUntraced(function* (
          providerThread: OrchestrationV2ProviderThread,
        ) {
          const sessionId = nativeThreadId(providerThread);
          const sessionResponse = yield* sdkCall("session.get", { sessionID: sessionId }, () =>
            client.session.get({ sessionID: sessionId }),
          );
          const nativeSession = unwrapData("session.get", sessionResponse);
          const response = yield* sdkCall("session.messages", { sessionID: sessionId }, () =>
            client.session.messages({ sessionID: sessionId }),
          );
          const nativeMessages = [];
          for (const entry of unwrapData("session.messages", response)) {
            // OpenCode retains reverted records in session.messages. Its
            // revert marker identifies the first removed message, so stop
            // before it or a restart resurrects rolled-back assistant work.
            if (entry.info.id === nativeSession.revert?.messageID) break;
            nativeMessages.push(entry);
          }
          const state = threads.get(sessionId);
          const snapshotNow = yield* DateTime.now;
          const messages: Array<OrchestrationV2ConversationMessage> = nativeMessages.flatMap(
            ({ info, parts }) => {
              const text = parts
                .filter(
                  (part): part is Extract<OpenCodePart, { type: "text" }> => part.type === "text",
                )
                .filter((part) => part.ignored !== true && part.synthetic !== true)
                .map((part) => part.text)
                .join("\n");
              if (text.length === 0) return [];
              const createdAt = dateTimeFromEpoch(info.time.created, snapshotNow);
              return [
                {
                  createdBy: info.role === "user" ? "user" : "agent",
                  creationSource: "provider",
                  id: idAllocator.derive.messageFromProviderItem({
                    driver: OPENCODE_PROVIDER,
                    nativeItemId: info.id,
                  }),
                  threadId: providerThread.appThreadId ?? input.threadId,
                  runId: null,
                  nodeId: null,
                  role: info.role,
                  text,
                  attachments: [],
                  streaming: false,
                  createdAt,
                  updatedAt:
                    info.role === "assistant"
                      ? dateTimeFromEpoch(info.time.completed, createdAt)
                      : createdAt,
                },
              ];
            },
          );
          const lastUser = nativeMessages.findLast(({ info }) => info.role === "user")?.info.id;
          return {
            providerThread: {
              ...providerThread,
              providerSessionId: input.providerSessionId,
              nativeConversationHeadRef:
                lastUser === undefined ? null : providerRef(lastUser, "weak"),
              status: "idle" as const,
              updatedAt: snapshotNow,
            },
            providerTurns: state === undefined ? [] : [...state.providerTurns.values()],
            messages,
            runtimeRequests: state === undefined ? [] : [...state.runtimeRequests.values()],
            providerPayload: nativeMessages,
          };
        });

        // Native commands wait for generation, unlike promptAsync. A user-message
        // receipt admits the run while the scoped request continues in the background.
        const submitPrompt = Effect.fn("OpenCode.submitPrompt")(function* (
          state: OpenCodeThreadState,
          turn: ActiveOpenCodeTurn,
          payload: Parameters<typeof client.session.promptAsync>[0] & {
            messageID: string;
            sessionID: string;
          },
          abortController: AbortController,
        ) {
          const text = payload.parts
            ?.filter((part) => part.type === "text")
            .map((part) => part.text)
            .join("\n")
            .trim();
          const match = text?.match(/^\/([^\s/]+)(?:\s+([\s\S]*))?$/);
          const command = match
            ? (yield* OpenCodeRuntime.loadOpenCodeCommands(client).pipe(
                Effect.timeout("10 seconds"),
                Effect.orElseSucceed(() => []),
              )).find((entry) => entry.name === match[1])
            : undefined;
          if (!command) {
            return yield* sdkCall("session.promptAsync", payload, (signal) =>
              client.session.promptAsync(payload, {
                signal: AbortSignal.any([signal, abortController.signal]),
              }),
            ).pipe(Effect.asVoid);
          }
          const receipt = Deferred.makeUnsafe<void>();
          commandReceipts.set(payload.messageID, receipt);
          const controllers =
            commandControllers.get(payload.sessionID) ?? new Set<AbortController>();
          controllers.add(abortController);
          commandControllers.set(payload.sessionID, controllers);
          const generation = turn.admissionGeneration;
          const commandPayload = {
            sessionID: payload.sessionID,
            messageID: payload.messageID,
            command: command.name,
            arguments: match?.[2] ?? "",
            ...(payload.model
              ? { model: `${payload.model.providerID}/${payload.model.modelID}` }
              : {}),
            ...(payload.agent ? { agent: payload.agent } : {}),
            ...(payload.variant ? { variant: payload.variant } : {}),
            parts: payload.parts?.filter((part) => part.type === "file") ?? [],
          };
          const request = yield* sdkCall("session.command", commandPayload, (signal) =>
            client.session.command(commandPayload, {
              signal: AbortSignal.any([signal, abortController.signal]),
            }),
          ).pipe(
            Effect.asVoid,
            Effect.tapError((cause) =>
              abortController.signal.aborted ||
              turn.finalized ||
              turn.admissionGeneration !== generation
                ? Effect.void
                : finalizeTurn(state, turn, "failed", {
                    failure: makeProviderFailure({ cause, class: "provider_error" }),
                  }),
            ),
            Effect.ensuring(
              Effect.sync(() => {
                commandReceipts.delete(payload.messageID);
                controllers.delete(abortController);
                if (controllers.size === 0) commandControllers.delete(payload.sessionID);
              }),
            ),
            Effect.forkIn(scope),
          );
          yield* Effect.raceFirst(Fiber.join(request), Deferred.await(receipt)).pipe(
            Effect.timeout("10 seconds"),
            Effect.catchTag("TimeoutError", (cause) => {
              const error = new OpenCodeRuntime.OpenCodeRuntimeError({
                operation: "session.command",
                detail: "OpenCode command admission did not complete within 10 seconds.",
                cause,
              });
              abortController.abort();
              return finalizeTurn(state, turn, "failed", {
                failure: makeProviderFailure({ cause: error, class: "provider_error" }),
              }).pipe(Effect.andThen(Effect.fail(error)));
            }),
          );
        });

        const runtimeSession: ProviderAdapter.ProviderAdapterV2SessionRuntime = {
          instanceId: options.instanceId,
          driver: OPENCODE_PROVIDER,
          providerSessionId: input.providerSessionId,
          providerSession: sessionEntity,
          events: Stream.fromEffectRepeat(Queue.take(events)),
          hasPendingBackgroundWork: Effect.sync(() => busySessionIds.size > 0),
          ensureThread: (threadInput) =>
            Effect.gen(function* () {
              // Only a row that already carries a native session can be
              // resumed; a placeholder without one still needs session.create.
              if (threadInput.existingProviderThread?.nativeThreadRef != null) {
                return yield* runtimeSession.resumeThread({
                  providerThread: threadInput.existingProviderThread,
                });
              }
              // No title: OpenCode generates one from the first prompt only when
              // session.create leaves it unset (SessionPrompt.ensureTitle).
              const response = yield* sdkCall(
                "session.create",
                { permission: openCodePermissionRules(threadInput.runtimePolicy) },
                () =>
                  client.session.create({
                    permission: openCodePermissionRules(threadInput.runtimePolicy),
                  }),
              );
              const nativeSession = unwrapData("session.create", response);
              const createdAt = yield* DateTime.now;
              const created = makeProviderThread({
                idAllocator,
                providerInstanceId: options.instanceId,
                providerSessionId: input.providerSessionId,
                appThreadId: threadInput.threadId,
                nativeSession,
                now: createdAt,
              });
              const existing = threadInput.existingProviderThread;
              // Bind the new native session to the caller's row when one was
              // handed over: a second live row per app thread would make
              // `activeProviderThreadId` flap between the two on every update.
              const providerThread =
                existing === undefined
                  ? created
                  : {
                      ...existing,
                      providerSessionId: input.providerSessionId,
                      nativeThreadRef: created.nativeThreadRef,
                      nativeConversationHeadRef: created.nativeConversationHeadRef,
                      status: created.status,
                      updatedAt: created.updatedAt,
                    };
              registerThread(nativeSession, providerThread, null);
              return providerThread;
            }).pipe(
              Effect.mapError(
                (cause) =>
                  new ProviderAdapter.ProviderAdapterEnsureThreadError({
                    driver: OPENCODE_PROVIDER,
                    threadId: threadInput.threadId,
                    cause,
                  }),
              ),
            ),
          resumeThread: (threadInput) =>
            Effect.gen(function* () {
              const sessionId = nativeThreadId(threadInput.providerThread);
              const response = yield* sdkCall("session.get", { sessionID: sessionId }, () =>
                client.session.get({ sessionID: sessionId }),
              );
              const nativeSession = unwrapData("session.get", response);
              const resumedAt = yield* DateTime.now;
              const providerThread = {
                ...threadInput.providerThread,
                providerSessionId: input.providerSessionId,
                status: "idle" as const,
                updatedAt: dateTimeFromEpoch(nativeSession.time.updated, resumedAt),
              };
              registerThread(nativeSession, providerThread, null);
              return providerThread;
            }).pipe(
              Effect.mapError(
                (cause) =>
                  new ProviderAdapter.ProviderAdapterResumeThreadError({
                    driver: OPENCODE_PROVIDER,
                    providerSessionId: input.providerSessionId,
                    providerThreadId: threadInput.providerThread.id,
                    cause,
                  }),
              ),
            ),
          compactThread: (turnInput) =>
            runtimeSession.startTurn({
              ...turnInput,
              message: { ...turnInput.message, text: "/compact" },
            }),
          startTurn: (turnInput) =>
            Effect.gen(function* () {
              if (nativeStreamFailure !== null) {
                return yield* protocolError(
                  "OpenCode event stream has ended; reconnect the provider session before starting another turn.",
                );
              }
              const sessionId = nativeThreadId(turnInput.providerThread);
              const state = threads.get(sessionId);
              if (state === undefined) {
                return yield* protocolError(`OpenCode session ${sessionId} is not registered`);
              }
              if (state.activeTurn !== null) {
                return yield* protocolError(
                  `OpenCode provider thread ${turnInput.providerThread.id} already has an active turn`,
                );
              }
              const parsedModel = OpenCodeRuntime.parseOpenCodeModelSlug(
                turnInput.modelSelection.model,
              );
              if (parsedModel === null) {
                return yield* protocolError(
                  `OpenCode model '${turnInput.modelSelection.model}' must use provider/model format`,
                );
              }
              const isCompaction =
                turnInput.message.text.trim() === "/compact" &&
                turnInput.message.attachments.length === 0;
              const parts = isCompaction ? [] : resolvePromptParts(turnInput);
              const startedAt = yield* DateTime.now;
              const syntheticNativeTurnId = `${sessionId}:attempt:${turnInput.attemptId}`;
              const providerTurnId = idAllocator.derive.providerTurn({
                driver: OPENCODE_PROVIDER,
                nativeTurnId: syntheticNativeTurnId,
              });
              const providerTurn: OrchestrationV2ProviderTurn = {
                id: providerTurnId,
                providerThreadId: turnInput.providerThread.id,
                nodeId: turnInput.rootNodeId,
                runAttemptId: turnInput.attemptId,
                nativeTurnRef: providerRef(syntheticNativeTurnId, "weak"),
                ordinal: turnInput.providerTurnOrdinal,
                status: "running",
                startedAt,
                completedAt: null,
              };
              const admissionMessageId = yield* makeOpenCodeMessageId();
              // No Effect may be yielded between this check and installing the
              // turn. If the event stream ended while IDs were being prepared,
              // registering afterward would leave a running turn that the EOF
              // handler had already finished scanning.
              if (nativeStreamFailure !== null) {
                return yield* protocolError(
                  "OpenCode event stream has ended; reconnect the provider session before starting another turn.",
                );
              }
              if (state.activeTurn !== null) {
                return yield* protocolError(
                  `OpenCode provider thread ${turnInput.providerThread.id} already has an active turn`,
                );
              }
              const turn: ActiveOpenCodeTurn = {
                isRoot: true,
                threadId: turnInput.threadId,
                runId: turnInput.runId,
                rootNodeId: turnInput.rootNodeId,
                appThread: turnInput.appThread,
                modelSelection: turnInput.modelSelection,
                runtimePolicy: turnInput.runtimePolicy,
                providerTurnId,
                providerTurnOrdinal: turnInput.providerTurnOrdinal,
                runOrdinal: turnInput.runOrdinal,
                runAttemptId: turnInput.attemptId,
                startedAt,
                itemOrdinals: new Map(),
                usage: makeOpenCodeTurnTokenUsageAccumulator(),
                parts: new Map(),
                partIdsByMessage: new Map(),
                toolNamesByCallId: new Map(),
                providerTurn,
                nextItemOrdinal: turnInput.providerTurnOrdinal * 100 + 1,
                nativeUserMessageId: null,
                admissionMessageId,
                interrupted: false,
                finalized: false,
                planId: null,
                admissionGeneration: state.nextAdmissionGeneration++,
                admissionReconciliationGeneration: null,
                admissionPending: !isCompaction,
                admissionAccepted: isCompaction,
                admissionMessageObserved: false,
                idleDuringAdmission: false,
                admissionSettled: Deferred.makeUnsafe<void>(),
                admissionAbortController: new AbortController(),
              };
              if (turn.admissionMessageId !== null)
                turn.usage.promptMessageIds.add(turn.admissionMessageId);
              const admissionSettled = turn.admissionSettled;
              const admissionAbortController = turn.admissionAbortController;
              state.appThread = turnInput.appThread;
              state.activeTurn = turn;
              state.providerTurns.set(String(providerTurnId), providerTurn);
              yield* emitProviderTurn(state, turn, "running", null);
              yield* updateProviderThread(state, {
                status: "active",
                firstRunOrdinal: state.providerThread.firstRunOrdinal ?? turnInput.runOrdinal,
                lastRunOrdinal: turnInput.runOrdinal,
              });
              yield* updateProviderSession("running", null);
              if (isCompaction) {
                yield* sdkCall(
                  "session.summarize",
                  { sessionID: sessionId, ...parsedModel, auto: false },
                  (signal) =>
                    client.session.summarize(
                      { sessionID: sessionId, ...parsedModel, auto: false },
                      { signal: AbortSignal.any([signal, admissionAbortController!.signal]) },
                    ),
                ).pipe(
                  Effect.tap(() =>
                    turn.interrupted || turn.finalized || nativeStreamFailure !== null
                      ? Effect.void
                      : emitCompactionItem(state, turn),
                  ),
                  Effect.tap(() =>
                    finalizeTurn(state, turn, turn.interrupted ? "interrupted" : "completed"),
                  ),
                  Effect.tapError((cause) =>
                    finalizeTurn(state, turn, turn.interrupted ? "interrupted" : "failed", {
                      failure: makeProviderFailure({ cause, class: "provider_error" }),
                    }),
                  ),
                  Effect.ensuring(Deferred.succeed(admissionSettled, undefined)),
                );
                return;
              }
              const systemPrompt = [
                orchestrationSystemPrompt,
                buildRuntimeInstructions({
                  harness: "OpenCode",
                  model: turnInput.modelSelection.model,
                }),
              ]
                .filter(Boolean)
                .join("\n\n");
              const agent =
                getModelSelectionStringOptionValue(turnInput.modelSelection, "agent") ??
                (turnInput.runtimePolicy.interactionMode === "plan" ? "plan" : undefined);
              const variant = getModelSelectionStringOptionValue(
                turnInput.modelSelection,
                "variant",
              );
              yield* submitPrompt(
                state,
                turn,
                {
                  sessionID: sessionId,
                  messageID: turn.admissionMessageId!,
                  model: parsedModel,
                  ...(agent === undefined ? {} : { agent }),
                  ...(variant === undefined ? {} : { variant }),
                  system: systemPrompt,
                  parts,
                },
                admissionAbortController!,
              ).pipe(
                Effect.tapError((cause) =>
                  admissionAbortController!.signal.aborted
                    ? Effect.void
                    : finalizeTurn(state, turn, "failed", {
                        failure: makeProviderFailure({ cause, class: "provider_error" }),
                      }),
                ),
                Effect.catch((cause) =>
                  admissionAbortController!.signal.aborted ? Effect.void : Effect.fail(cause),
                ),
                Effect.ensuring(
                  Effect.all([
                    Deferred.succeed(admissionSettled, undefined).pipe(Effect.ignore),
                    Effect.sync(() => {
                      if (turn.admissionAbortController === admissionAbortController) {
                        turn.admissionAbortController = null;
                      }
                    }),
                  ]).pipe(Effect.asVoid),
                ),
              );
              if (state.activeTurn === turn && !turn.finalized && !turn.interrupted) {
                const admissionAction = advanceOpenCodePromptAdmission(turn, "accepted");
                if (admissionAction === "reconcile-idle") {
                  yield* reconcilePromptAdmission(state, turn);
                }
              }
            }).pipe(
              Effect.mapError(
                (cause) =>
                  new ProviderAdapter.ProviderAdapterTurnStartError({
                    driver: OPENCODE_PROVIDER,
                    threadId: turnInput.threadId,
                    providerThreadId: turnInput.providerThread.id,
                    runId: turnInput.runId,
                    cause,
                  }),
              ),
            ),
          steerTurn: (steerInput) =>
            Effect.gen(function* () {
              const sessionId = nativeThreadId(steerInput.providerThread);
              const state = threads.get(sessionId);
              const turn = state?.activeTurn;
              if (
                state === undefined ||
                turn === undefined ||
                turn === null ||
                turn.providerTurnId !== steerInput.providerTurnId ||
                turn.interrupted
              ) {
                return yield* protocolError(
                  `OpenCode turn ${steerInput.providerTurnId} is not active`,
                );
              }
              const parsedModel = OpenCodeRuntime.parseOpenCodeModelSlug(turn.modelSelection.model);
              if (parsedModel === null) {
                return yield* protocolError(
                  `OpenCode model '${turn.modelSelection.model}' must use provider/model format`,
                );
              }
              const text = providerMessageTextWithAttachmentPaths({
                text: steerInput.message.text,
                attachments: steerInput.message.attachments,
                attachmentsDir: serverConfig.attachmentsDir,
              }).trim();
              const files = OpenCodeRuntime.toOpenCodeFileParts({
                attachments: steerInput.message.attachments,
                resolveAttachmentPath: (attachment) =>
                  resolveAttachmentPath({
                    attachmentsDir: serverConfig.attachmentsDir,
                    attachment,
                  }),
              });
              if (text.length === 0 && files.length === 0) {
                return yield* protocolError("OpenCode steering requires text or an attachment");
              }
              const parts = [
                ...(text.length === 0 ? [] : [{ type: "text" as const, text }]),
                ...files,
              ];
              turn.admissionGeneration = state.nextAdmissionGeneration++;
              turn.admissionMessageId = yield* makeOpenCodeMessageId();
              turn.admissionPending = true;
              turn.admissionAccepted = false;
              turn.admissionMessageObserved = false;
              turn.idleDuringAdmission = false;
              turn.admissionSettled = Deferred.makeUnsafe<void>();
              turn.admissionAbortController = new AbortController();
              if (turn.admissionMessageId !== null)
                turn.usage.promptMessageIds.add(turn.admissionMessageId);
              const admissionSettled = turn.admissionSettled;
              const admissionAbortController = turn.admissionAbortController;
              yield* submitPrompt(
                state,
                turn,
                {
                  sessionID: sessionId,
                  messageID: turn.admissionMessageId,
                  model: parsedModel,
                  parts,
                },
                admissionAbortController!,
              ).pipe(
                Effect.ensuring(
                  Effect.all([
                    Deferred.succeed(admissionSettled, undefined).pipe(Effect.ignore),
                    Effect.sync(() => {
                      if (turn.admissionAbortController === admissionAbortController) {
                        turn.admissionAbortController = null;
                      }
                    }),
                  ]).pipe(Effect.asVoid),
                ),
              );
              if (state.activeTurn === turn && !turn.finalized) {
                const admissionAction = advanceOpenCodePromptAdmission(turn, "accepted");
                if (admissionAction === "reconcile-idle") {
                  yield* reconcilePromptAdmission(state, turn);
                }
              }
            }).pipe(
              Effect.mapError(
                (cause) =>
                  new ProviderAdapter.ProviderAdapterSteerRunError({
                    driver: OPENCODE_PROVIDER,
                    providerThreadId: steerInput.providerThread.id,
                    providerTurnId: steerInput.providerTurnId,
                    cause,
                  }),
              ),
            ),
          interruptTurn: (interruptInput) =>
            Effect.gen(function* () {
              const sessionId = nativeThreadId(interruptInput.providerThread);
              const state = threads.get(sessionId);
              const turn = state?.activeTurn;
              // Stop on a settled turn: a background task child can outlive
              // it (busySessionIds), and aborting the descendants ends it.
              if (
                (turn === undefined || turn === null) &&
                interruptInput.requestRuntimeRestart === true
              ) {
                for (const controller of commandControllers.get(sessionId) ?? [])
                  controller.abort();
                yield* abortDescendants(sessionId);
                return;
              }
              if (
                turn === undefined ||
                turn === null ||
                turn.providerTurnId !== interruptInput.providerTurnId
              ) {
                return yield* protocolError(
                  `OpenCode turn ${interruptInput.providerTurnId} is not active`,
                );
              }
              turn.interrupted = true;
              for (const controller of commandControllers.get(sessionId) ?? []) controller.abort();
              const admissionWasPending = turn.admissionPending;
              cancelOpenCodePromptAdmission(turn, state!.nextAdmissionGeneration++);
              turn.admissionAbortController?.abort();
              if (admissionWasPending) {
                // Settle the cancelled request before sending the session abort.
                // A timed-out local request must not prevent the definitive
                // server-side abort below from running.
                yield* Deferred.await(turn.admissionSettled).pipe(
                  Effect.timeout("10 seconds"),
                  Effect.ignore,
                );
              }
              yield* sdkCall("session.abort", { sessionID: sessionId }, (signal) =>
                client.session.abort({ sessionID: sessionId }, { signal }),
              ).pipe(
                Effect.timeout("10 seconds"),
                // The turn can settle while the abort is in flight, and
                // aborting an already-idle session fails. That stop still
                // succeeded; only surface failures for a turn that is
                // genuinely still running.
                Effect.catch((cause) =>
                  turn.finalized
                    ? Effect.void
                    : Effect.suspend(() => {
                        turn.interrupted = false;
                        return Effect.fail(cause);
                      }),
                ),
              );
              // Root abort does not stop child sessions. Report incomplete cleanup
              // even if the root has already emitted its terminal event.
              yield* abortDescendants(sessionId);
            }).pipe(
              Effect.mapError(
                (cause) =>
                  new ProviderAdapter.ProviderAdapterInterruptError({
                    driver: OPENCODE_PROVIDER,
                    providerThreadId: interruptInput.providerThread.id,
                    providerTurnId: interruptInput.providerTurnId,
                    cause,
                  }),
              ),
            ),
          respondToRuntimeRequest: (requestInput) =>
            Effect.gen(function* () {
              const pending = pendingRequests.get(String(requestInput.requestId));
              if (pending === undefined) {
                return yield* protocolError(
                  `No pending OpenCode request ${requestInput.requestId}`,
                );
              }
              if (pending.question !== undefined) {
                if (requestInput.answers === undefined) {
                  return yield* protocolError(
                    `OpenCode question request ${requestInput.requestId} requires answers`,
                  );
                }
                const answers = OpenCodeRuntime.toOpenCodeQuestionAnswers(
                  pending.question,
                  requestInput.answers,
                );
                yield* sdkCall(
                  "question.reply",
                  { requestID: pending.nativeRequestId, answers },
                  (signal) =>
                    client.question.reply(
                      {
                        requestID: pending.nativeRequestId,
                        answers,
                      },
                      { signal },
                    ),
                ).pipe(Effect.timeout("10 seconds"));
                return;
              }
              if (requestInput.decision === undefined) {
                return yield* protocolError(
                  `OpenCode approval request ${requestInput.requestId} requires a decision`,
                );
              }
              const reply = OpenCodeRuntime.toOpenCodePermissionReply(requestInput.decision);
              yield* sdkCall(
                "permission.reply",
                { requestID: pending.nativeRequestId, reply },
                (signal) =>
                  client.permission.reply(
                    {
                      requestID: pending.nativeRequestId,
                      reply,
                    },
                    { signal },
                  ),
              ).pipe(Effect.timeout("10 seconds"));
            }).pipe(
              Effect.mapError(
                (cause) =>
                  new ProviderAdapter.ProviderAdapterRuntimeRequestResponseError({
                    driver: OPENCODE_PROVIDER,
                    requestId: requestInput.requestId,
                    cause,
                  }),
              ),
            ),
          readThreadSnapshot: (snapshotInput) =>
            readSnapshot(snapshotInput.providerThread).pipe(
              Effect.mapError(
                (cause) =>
                  new ProviderAdapter.ProviderAdapterReadThreadSnapshotError({
                    driver: OPENCODE_PROVIDER,
                    providerThreadId: snapshotInput.providerThread.id,
                    cause,
                  }),
              ),
            ),
          rollbackThread: (rollbackInput) =>
            Effect.gen(function* () {
              const sessionId = nativeThreadId(rollbackInput.providerThread);
              const state = threads.get(sessionId);
              if (state?.activeTurn !== null && state?.activeTurn !== undefined) {
                return yield* protocolError(
                  `Cannot roll back OpenCode thread ${rollbackInput.providerThread.id} while a turn is active`,
                );
              }
              const response = yield* sdkCall("session.messages", { sessionID: sessionId }, () =>
                client.session.messages({ sessionID: sessionId }),
              );
              const messages = unwrapData("session.messages", response);
              let boundaryMessageId: string | undefined;
              if (rollbackInput.target.type === "thread_start") {
                boundaryMessageId = messages.find(({ info }) => info.role === "user")?.info.id;
              } else {
                boundaryMessageId = openCodeBoundaryAfterProviderTurn(
                  rollbackInput.providerThreadTurns,
                  rollbackInput.target.providerTurn.id,
                );
              }
              let retainedThread = rollbackInput.providerThread;
              if (boundaryMessageId !== undefined) {
                const boundaryIndex = messages.findIndex(
                  ({ info }) => info.id === boundaryMessageId,
                );
                if (boundaryIndex < 0)
                  return yield* protocolError(
                    "The OpenCode rewind boundary is no longer available.",
                  );
                const fork = unwrapData(
                  "session.fork",
                  yield* sdkCall(
                    "session.fork",
                    { sessionID: sessionId, messageID: boundaryMessageId },
                    () =>
                      client.session.fork({ sessionID: sessionId, messageID: boundaryMessageId }),
                  ),
                );
                const retained = unwrapData(
                  "session.messages",
                  yield* sdkCall("session.messages", { sessionID: fork.id }, () =>
                    client.session.messages({ sessionID: fork.id }),
                  ),
                );
                if (retained.length !== boundaryIndex)
                  return yield* protocolError(
                    "OpenCode did not preserve the requested rewind boundary.",
                  );
                yield* sdkCall("session.update", { sessionID: fork.id }, () =>
                  client.session.update({
                    sessionID: fork.id,
                    permission: openCodePermissionRules(input.runtimePolicy),
                  }),
                );
                retainedThread = {
                  ...rollbackInput.providerThread,
                  nativeThreadRef: providerRef(fork.id),
                };
                registerThread(fork, retainedThread, state?.appThread ?? null);
              }
              const snapshot = yield* readSnapshot(retainedThread);
              return {
                ...snapshot,
                providerThread: {
                  ...snapshot.providerThread,
                  nativeConversationHeadRef:
                    rollbackInput.target.type === "provider_turn"
                      ? rollbackInput.target.providerTurn.nativeTurnRef
                      : null,
                },
              };
            }).pipe(
              Effect.mapError(
                (cause) =>
                  new ProviderAdapter.ProviderAdapterRollbackThreadError({
                    driver: OPENCODE_PROVIDER,
                    providerThreadId: rollbackInput.providerThread.id,
                    checkpointId: rollbackInput.target.checkpointId,
                    cause,
                  }),
              ),
            ),
          forkThread: (forkInput) =>
            Effect.gen(function* () {
              const sourceSessionId = nativeThreadId(forkInput.sourceProviderThread);
              const sourceState = threads.get(sourceSessionId);
              if (sourceState?.activeTurn !== null && sourceState?.activeTurn !== undefined) {
                return yield* protocolError(
                  `Cannot fork OpenCode thread ${forkInput.sourceProviderThread.id} while a turn is active`,
                );
              }
              let boundaryMessageId: string | undefined;
              if (forkInput.providerTurnId !== undefined) {
                const sourceTurns = forkInput.sourceProviderTurns ?? [];
                const selected = sourceTurns.find((turn) => turn.id === forkInput.providerTurnId);
                if (selected === undefined) {
                  return yield* protocolError(
                    `OpenCode fork boundary turn ${forkInput.providerTurnId} was not found`,
                  );
                }
                boundaryMessageId = openCodeBoundaryAfterProviderTurn(sourceTurns, selected.id);
              }
              const response = yield* sdkCall(
                "session.fork",
                {
                  sessionID: sourceSessionId,
                  ...(boundaryMessageId === undefined ? {} : { messageID: boundaryMessageId }),
                },
                () =>
                  client.session.fork({
                    sessionID: sourceSessionId,
                    ...(boundaryMessageId === undefined ? {} : { messageID: boundaryMessageId }),
                  }),
              );
              const nativeSession = unwrapData("session.fork", response);
              const forkedAt = yield* DateTime.now;
              const providerThread = makeProviderThread({
                idAllocator,
                providerInstanceId: options.instanceId,
                providerSessionId: input.providerSessionId,
                appThreadId: forkInput.targetThreadId,
                ...(forkInput.ownerNodeId === undefined
                  ? {}
                  : { ownerNodeId: forkInput.ownerNodeId }),
                nativeSession,
                forkedFrom: {
                  providerThreadId: forkInput.sourceProviderThread.id,
                  ...(forkInput.providerTurnId === undefined
                    ? {}
                    : { providerTurnId: forkInput.providerTurnId }),
                },
                now: forkedAt,
              });
              registerThread(nativeSession, providerThread, null);
              return providerThread;
            }).pipe(
              Effect.mapError(
                (cause) =>
                  new ProviderAdapter.ProviderAdapterForkThreadError({
                    driver: OPENCODE_PROVIDER,
                    providerThreadId: forkInput.sourceProviderThread.id,
                    cause,
                  }),
              ),
            ),
        };

        return runtimeSession;
      },
      (effect, input) =>
        effect.pipe(
          Effect.mapError(
            (cause) =>
              new ProviderAdapter.ProviderAdapterOpenSessionError({
                driver: OPENCODE_PROVIDER,
                providerSessionId: input.providerSessionId,
                cause,
              }),
          ),
        ),
    ),
  });
}

export type OpenCodeAdapterV2DriverEnv =
  | OpenCodeRuntime.OpenCodeRuntime
  | IdAllocator.IdAllocatorV2
  | ProviderEventLoggers.ProviderEventLoggers
  | ServerConfig.ServerConfig;

export const OpenCodeAdapterV2Driver: ProviderAdapterDriver<
  OpenCodeSettings,
  OpenCodeAdapterV2DriverEnv
> = {
  driverKind: OPENCODE_PROVIDER,
  configSchema: OpenCodeSettingsSchema,
  defaultConfig: (): OpenCodeSettings => DEFAULT_OPENCODE_SETTINGS,
  create: Effect.fn("OpenCodeAdapterV2Driver.create")(
    function* (input: ProviderAdapterDriverCreateInput<OpenCodeSettings>) {
      const hostEnvironment = yield* HostProcessEnvironment;
      const openCodeRuntime = yield* OpenCodeRuntime.OpenCodeRuntime;
      const idAllocator = yield* IdAllocator.IdAllocatorV2;
      const providerEventLoggers = yield* ProviderEventLoggers.ProviderEventLoggers;
      const serverConfig = yield* ServerConfig.ServerConfig;
      return makeOpenCodeAdapterV2({
        instanceId: input.instanceId,
        settings: { ...input.config, enabled: input.enabled },
        environment: mergeProviderInstanceEnvironment(input.environment, hostEnvironment),
        runtime: openCodeRuntime,
        idAllocator,
        serverConfig,
        ...(providerEventLoggers.native === undefined
          ? {}
          : { nativeEventLogger: providerEventLoggers.native }),
      });
    },
    (effect, input) =>
      effect.pipe(
        Effect.mapError(
          (cause) =>
            new ProviderAdapterDriverCreateError({
              driver: OPENCODE_PROVIDER,
              instanceId: input.instanceId,
              detail: "Failed to create OpenCode v2 adapter.",
              cause,
            }),
        ),
      ),
  ),
};

const layer: Layer.Layer<ProviderAdapter.ProviderAdapterV2, never, OpenCodeAdapterV2DriverEnv> =
  Layer.effect(
    ProviderAdapter.ProviderAdapterV2,
    Effect.gen(function* () {
      const hostEnvironment = yield* HostProcessEnvironment;
      const openCodeRuntime = yield* OpenCodeRuntime.OpenCodeRuntime;
      const idAllocator = yield* IdAllocator.IdAllocatorV2;
      const providerEventLoggers = yield* ProviderEventLoggers.ProviderEventLoggers;
      const serverConfig = yield* ServerConfig.ServerConfig;
      return makeOpenCodeAdapterV2({
        instanceId: OPENCODE_DEFAULT_INSTANCE_ID,
        settings: DEFAULT_OPENCODE_SETTINGS,
        environment: hostEnvironment,
        runtime: openCodeRuntime,
        idAllocator,
        serverConfig,
        ...(providerEventLoggers.native === undefined
          ? {}
          : { nativeEventLogger: providerEventLoggers.native }),
      });
    }),
  );