callstack
diff --git a/‎packages/contracts/src/element-text-runtime.test.ts‎
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diff --git a/‎packages/contracts/src/element-text-runtime.ts‎
Lines changed: 120 additions & 0 deletions b/‎packages/contracts/src/element-text-runtime.ts‎
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diff --git a/‎packages/contracts/src/facades/platform.ts‎
Lines changed: 20 additions & 1 deletion b/‎packages/contracts/src/facades/platform.ts‎
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diff --git a/‎packages/contracts/src/interactor-types.ts‎
Lines changed: 10 additions & 0 deletions b/‎packages/contracts/src/interactor-types.ts‎
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@@ -0,0 +1,97 @@
+import assert from 'node:assert/strict';
+import { test } from 'vitest';
+import { AppError } from '@agent-device/kernel/errors';
+import {
+  bindElementTextRuntime,
+  elementTextRead,
+  type ElementTextReadOutcome,
+  type ElementTextUnreadableReason,
+} from './element-text-runtime.ts';
+import type { Interactor } from './interactor-types.ts';
+import type { DeviceInfo } from '@agent-device/kernel/device';
+
+/**
+ * The reasons this suite exercises. Kept local on purpose: exhaustiveness is enforced at the
+ * CONSUMER by `classifiedFallbackReason`'s `never` arm (a new reason is a compile error there),
+ * so a second exported runtime list would be an unconsumed parallel source of truth that could
+ * silently drift. The annotation is what ties this list back to the union.
+ */
+const UNREADABLE_REASONS: readonly ElementTextUnreadableReason[] = ['no-text-at-point'];
+
+/**
+ * ADR 0019 §2 contract coverage for the preferred element-text read.
+ *
+ * A preferred operation may fall its consumer back to the required path only through a TYPED
+ * reason. These tests pin that the reason set is closed and exhaustively enumerated, so a new
+ * reason cannot be added without a consumer having to classify it — which is what keeps the
+ * retired generic `catch` from creeping back as "some other failure, just fall back".
+ */
+
+test('the outcome union is closed: every value is a read or a classified unreadable', () => {
+  const outcomes: readonly ElementTextReadOutcome[] = [
+    elementTextRead('live value'),
+    ...UNREADABLE_REASONS.map((reason) => ({ status: 'unreadable', reason }) as const),
+  ];
+  for (const outcome of outcomes) {
+    if (outcome.status === 'read') {
+      assert.equal(typeof outcome.text, 'string');
+      continue;
+    }
+    assert.ok(
+      (UNREADABLE_REASONS as readonly string[]).includes(outcome.reason),
+      `unreadable outcome carries an unclassified reason: ${outcome.reason}`,
+    );
+  }
+});
+
+test('a non-blank owner answer is a read that preserves the exact text', () => {
+  const outcome = elementTextRead('  padded value  ');
+  assert.deepEqual(outcome, { status: 'read', text: '  padded value  ' });
+});
+
+// Blank is a classification, not a read: an owner answering with whitespace has said there is
+// nothing at this point, and saying so by reason keeps consumers off "empty or failed?" guesswork.
+for (const [label, value] of [
+  ['empty string', ''],
+  ['whitespace', '   \n\t '],
+  ['undefined', undefined],
+  ['null', null],
+] as const) {
+  test(`a ${label} owner answer classifies as no-text-at-point`, () => {
+    assert.deepEqual(elementTextRead(value), {
+      status: 'unreadable',
+      reason: 'no-text-at-point',
+    });
+  });
+}
+
+test('read outcomes are frozen so a consumer cannot mutate a classification', () => {
+  assert.ok(Object.isFrozen(elementTextRead('value')));
+  assert.ok(Object.isFrozen(elementTextRead('')));
+});
+
+/**
+ * A runtime owner whose facts advertised `readTextAtPoint` but whose interactor cannot perform
+ * it is a CONTRACT BUG, not a refusal. Classifying it as an unreadable reason would place it
+ * inside the closed set that licenses falling back to already-captured text — so the command
+ * would answer from a stale tree precisely because the runtime lied about itself.
+ *
+ * Reverting the guard to `{ status: 'unreadable', reason: … }` makes this test fail: the call
+ * resolves instead of rejecting, which is the exact silent degradation it exists to forbid.
+ */
+test('an advertised read with no interactor implementation fails as a contract bug', async () => {
+  const runtime = bindElementTextRuntime({
+    device: { platform: 'ios' } as unknown as DeviceInfo,
+    signal: new AbortController().signal,
+    // An interactor with NO readTextAtPoint — the mismatch the facts promised away.
+    resolveInteractor: async () => ({}) as unknown as Interactor,
+  });
+
+  await assert.rejects(
+    () => runtime.readTextAtPoint({ point: { x: 1, y: 2 } }),
+    (error: unknown) =>
+      error instanceof AppError &&
+      error.details?.reason === 'runtime-contract-invalid' &&
+      /advertised readTextAtPoint/.test(error.message),
+  );
+});
@@ -0,0 +1,120 @@
+import type { DeviceInfo } from '@agent-device/kernel/device';
+import type { Point } from '@agent-device/kernel/snapshot';
+import type { Interactor, RunnerContext } from './interactor-types.ts';
+import { invalidRuntimeContract } from './runtime-contract-error.ts';
+import type { RuntimeOperationFact } from './platform-runtime.ts';
+import type { SessionSurface } from './session-surface.ts';
+import type { SnapshotRuntimeExecution } from './snapshot-runtime.ts';
+
+/**
+ * Neutral intent for one point-addressed element read. The point is already resolved from the
+ * node the caller matched, so the operation names no command, request, session, or CLI flag.
+ */
+export type ReadTextAtPointInput = Readonly<{
+  point: Point;
+  options?: Readonly<{ appBundleId?: string; surface?: SessionSurface }>;
+  /** Same runner metadata a capture needs; reuses that type rather than restating it. */
+  execution?: SnapshotRuntimeExecution;
+}>;
+
+/**
+ * Why an owner that HAS a live read still produced no text for this point.
+ *
+ * Closed on purpose (ADR 0019 §2): a consumer may fall back to the required path only for a
+ * reason named here. Anything else — a runner transport failure, a helper crash, a bug — is an
+ * unexpected error and propagates, because silently answering from a stale captured tree after
+ * an unclassified failure is exactly the "generic catch fallback" the ADR forbids.
+ */
+export type ElementTextUnreadableReason =
+  /** The owner queried successfully and there is nothing readable at this point. */
+  'no-text-at-point';
+
+/** The closed outcome of one live element-text read. */
+export type ElementTextReadOutcome =
+  | Readonly<{ status: 'read'; text: string }>
+  | Readonly<{ status: 'unreadable'; reason: ElementTextUnreadableReason }>;
+
+/**
+ * Normalizes a raw owner read into the closed outcome. Blank text is not a read: an owner that
+ * answers with whitespace has told us there is nothing at this point, and saying so by reason
+ * keeps every consumer off "did it fail or is it empty?" guesswork.
+ */
+export function elementTextRead(text: string | undefined | null): ElementTextReadOutcome {
+  if (typeof text !== 'string' || text.trim().length === 0) {
+    return Object.freeze({ status: 'unreadable', reason: 'no-text-at-point' } as const);
+  }
+  return Object.freeze({ status: 'read', text } as const);
+}
+
+export type ElementTextRuntimeOperations = Readonly<{
+  /**
+   * The live text an owner reads at a point, which can exceed the readable text carried by an
+   * already-captured snapshot node (an editable field whose value is longer than its label).
+   * Declared `preferred`, never `required`: every consumer's required path answers from the
+   * snapshot tree, so an owner without this operation still executes the command completely.
+   *
+   * Returns a closed typed outcome rather than a bare string, so a consumer never has to
+   * distinguish "no text here" from "the read blew up" by catching.
+   */
+  readTextAtPoint(input: ReadTextAtPointInput): Promise<ElementTextReadOutcome>;
+}>;
+
+export type ElementTextRuntimeOperationFacts = Readonly<{
+  readTextAtPoint: RuntimeOperationFact;
+}>;
+
+export function elementTextRuntimeOperationFacts(
+  input: ElementTextRuntimeOperationFacts,
+): ElementTextRuntimeOperationFacts {
+  return Object.freeze({ readTextAtPoint: input.readTextAtPoint });
+}
+
+/** Resolves the selected owner's interactor, exactly as the snapshot runtime does. */
+export type ElementTextInteractorResolver = (
+  device: DeviceInfo,
+  runner: RunnerContext,
+) => Promise<Interactor>;
+
+/**
+ * Binds the owner's live point read for the lifetime of a request binding.
+ *
+ * Rides the same `Interactor` seam `findText` uses rather than a bespoke host port: two
+ * operations of the same class reaching their mechanics two different ways is duplication of
+ * mechanism, and Wave 5/6 retires the seam for both together.
+ */
+export function bindElementTextRuntime(
+  params: Readonly<{
+    device: DeviceInfo;
+    signal: AbortSignal;
+    resolveInteractor: ElementTextInteractorResolver;
+  }>,
+): ElementTextRuntimeOperations {
+  return Object.freeze({
+    readTextAtPoint: async (input: ReadTextAtPointInput) => {
+      const signal = params.signal;
+      signal.throwIfAborted();
+      const interactor = await params.resolveInteractor(params.device, {
+        ...input.execution,
+        appBundleId: input.options?.appBundleId,
+        signal,
+      });
+      // Facts advertised the read but the owner's interactor cannot perform it. That is a
+      // contract violation, not a refusal: classifying it as `surface-not-readable` would put
+      // it inside the closed reason set and license the caller to fall back to already-captured
+      // text, answering from a stale tree because the runtime lied. Fail as the contract bug it
+      // is (ADR 0019 §2) so no consumer can silently degrade.
+      if (typeof interactor.readTextAtPoint !== 'function') {
+        throw invalidRuntimeContract(
+          'Runtime owner advertised readTextAtPoint without an interactor implementation',
+        );
+      }
+      return elementTextRead(
+        await interactor.readTextAtPoint(input.point, {
+          appBundleId: input.options?.appBundleId,
+          surface: input.options?.surface,
+          signal,
+        }),
+      );
+    },
+  });
+}
@@ -214,12 +214,18 @@ export {
   captureSnapshotUse,
   defineUse,
   resolveScreenshotRuntimePlan,
+  resolveSelectorCaptureRuntimePlan,
   resolveSnapshotRuntimePlan,
   screenshotRuntimePlanUses,
+  selectorCaptureRuntimePlanUses,
   snapshotRuntimePlanUses,
   viewportRuntimeUse,
 } from '../platform-runtime-operations.ts';
-export type { ScreenshotRuntimePlan, SnapshotRuntimePlan } from '../platform-runtime-operations.ts';
+export type {
+  ScreenshotRuntimePlan,
+  SelectorCaptureRuntimePlan,
+  SnapshotRuntimePlan,
+} from '../platform-runtime-operations.ts';
 export type {
   PlatformRuntimeHost,
   PlatformRuntimeModule,
@@ -270,6 +276,19 @@ export type {
   ViewportRuntimeOperationFacts,
   ViewportRuntimeOperations,
 } from '../viewport-runtime.ts';
+export {
+  bindElementTextRuntime,
+  elementTextRead,
+  elementTextRuntimeOperationFacts,
+} from '../element-text-runtime.ts';
+export type {
+  ElementTextReadOutcome,
+  ElementTextInteractorResolver,
+  ElementTextRuntimeOperationFacts,
+  ElementTextRuntimeOperations,
+  ElementTextUnreadableReason,
+  ReadTextAtPointInput,
+} from '../element-text-runtime.ts';
 export type {
   AppStateRuntimeCommand,
   AppStateRuntimeCommandResult,
 
@@ -222,6 +222,16 @@ export type Interactor = {
   screenshot(outPath: string, options?: ScreenshotOptions): Promise<void>;
   setViewport?(width: number, height: number): Promise<Record<string, unknown> | void>;
   snapshot(options?: SnapshotOptions): Promise<SnapshotResult>;
+  /**
+   * Native reading of the live text at a point, when the backend has one. Answers the text the
+   * owner can see right now, which can exceed what an already-captured node carries (an editable
+   * field whose value is longer than its label). Optional: a backend without it leaves the
+   * captured tree as the complete answer.
+   */
+  readTextAtPoint?(
+    point: Point,
+    options?: { appBundleId?: string; surface?: SessionSurface; signal?: AbortSignal },
+  ): Promise<string | undefined>;
   gestureViewport?(): Promise<Rect>;
   back(mode?: BackMode): Promise<void>;
   home(): Promise<void>;