diff --git a/LifeOS/install/LIFEOS/TOOLS/Inference.autostate.test.ts b/LifeOS/install/LIFEOS/TOOLS/Inference.autostate.test.ts
new file mode 100644
index 0000000000..59ccdf740f
--- /dev/null
+++ b/LifeOS/install/LIFEOS/TOOLS/Inference.autostate.test.ts
@@ -0,0 +1,133 @@
+/**
+ * Inference.autostate.test.ts — session-resolution contract for
+ * synthesizeAdvisorState() (the --mode advisor --auto-state path).
+ *
+ * Runs in-process: the function resolves everything from $HOME, so each test
+ * points HOME at a throwaway tree. No inference call is ever made — only the
+ * state-synthesis step is exercised. Run with: bun test Inference.autostate.test.ts
+ */
+
+import { test, expect, beforeEach, afterEach } from "bun:test";
+import { mkdtempSync, mkdirSync, writeFileSync } from "fs";
+import { tmpdir } from "os";
+import { join } from "path";
+import { synthesizeAdvisorState } from "./Inference";
+
+const MIN = 60 * 1000;
+const iso = (agoMs: number) => new Date(Date.now() - agoMs).toISOString();
+
+const UUID_A = "aaaaaaaa-0000-0000-0000-000000000001";
+const UUID_B = "aaaaaaaa-0000-0000-0000-000000000002";
+
+let savedHome: string | undefined;
+let savedUserProfile: string | undefined;
+let savedSessionId: string | undefined;
+
+beforeEach(() => {
+  savedHome = process.env.HOME;
+  savedUserProfile = process.env.USERPROFILE;
+  savedSessionId = process.env.CLAUDE_SESSION_ID;
+  delete process.env.CLAUDE_SESSION_ID;
+});
+
+afterEach(() => {
+  if (savedHome !== undefined) process.env.HOME = savedHome; else delete process.env.HOME;
+  if (savedUserProfile !== undefined) process.env.USERPROFILE = savedUserProfile; else delete process.env.USERPROFILE;
+  if (savedSessionId !== undefined) process.env.CLAUDE_SESSION_ID = savedSessionId; else delete process.env.CLAUDE_SESSION_ID;
+});
+
+/** Build a throwaway $HOME with a registry and one ISA.md per session slug. */
+function fixture(sessions: Record<string, any>): void {
+  const home = mkdtempSync(join(tmpdir(), "inference-test-"));
+  const memory = join(home, ".claude", "LIFEOS", "MEMORY");
+  mkdirSync(join(memory, "STATE"), { recursive: true });
+  writeFileSync(join(memory, "STATE", "work.json"), JSON.stringify({ sessions }, null, 2));
+  for (const slug of Object.keys(sessions)) {
+    if (slug === "__pulse_strip") continue;
+    mkdirSync(join(memory, "WORK", slug), { recursive: true });
+    writeFileSync(join(memory, "WORK", slug, "ISA.md"), `# ISA for ${slug}\nbody\n`);
+  }
+  process.env.HOME = home;
+  process.env.USERPROFILE = home;
+}
+
+function row(overrides: Record<string, any> = {}) {
+  return { mode: "interactive", currentMode: "algorithm", phase: "build", updatedAt: iso(1 * MIN), ...overrides };
+}
+
+test("CLAUDE_SESSION_ID match wins, including its phase:complete row", async () => {
+  fixture({
+    "session-a": row({ sessionUUID: UUID_A, phase: "complete", updatedAt: iso(2 * MIN) }),
+    "session-b": row({ sessionUUID: UUID_B, phase: "build" }),
+  });
+  process.env.CLAUDE_SESSION_ID = UUID_A;
+  const state = await synthesizeAdvisorState();
+  expect(state).toContain("ISA: session-a");
+});
+
+test("CLAUDE_SESSION_ID set but unmatched: no state, never a guess", async () => {
+  fixture({ "session-a": row({ sessionUUID: UUID_A }) });
+  process.env.CLAUDE_SESSION_ID = "aaaaaaaa-0000-0000-0000-00000000dead";
+  const state = await synthesizeAdvisorState();
+  expect(state).toContain("ADVISOR STATE UNAVAILABLE");
+});
+
+test("no env, single fresh live session: uses its ISA", async () => {
+  fixture({ "session-a": row({ sessionUUID: UUID_A }) });
+  const state = await synthesizeAdvisorState();
+  expect(state).toContain("ISA: session-a");
+});
+
+test("no env, two fresh live sessions: no state", async () => {
+  fixture({
+    "session-a": row({ sessionUUID: UUID_A }),
+    "session-b": row({ sessionUUID: UUID_B }),
+  });
+  const state = await synthesizeAdvisorState();
+  expect(state).toContain("ADVISOR STATE UNAVAILABLE");
+});
+
+test("completion boundary: complete row from 2min ago, no live rows: uses it", async () => {
+  fixture({ "session-a": row({ sessionUUID: UUID_A, phase: "complete", updatedAt: iso(2 * MIN) }) });
+  const state = await synthesizeAdvisorState();
+  expect(state).toContain("ISA: session-a");
+});
+
+test("two recent completes, no live: most recently updated wins", async () => {
+  fixture({
+    "session-a": row({ sessionUUID: UUID_A, phase: "complete", updatedAt: iso(4 * MIN) }),
+    "session-b": row({ sessionUUID: UUID_B, phase: "complete", updatedAt: iso(1 * MIN) }),
+  });
+  const state = await synthesizeAdvisorState();
+  expect(state).toContain("ISA: session-b");
+});
+
+test("recent complete AND a live row: ambiguous, no state", async () => {
+  fixture({
+    "session-a": row({ sessionUUID: UUID_A, phase: "complete", updatedAt: iso(2 * MIN) }),
+    "session-b": row({ sessionUUID: UUID_B, phase: "build" }),
+  });
+  const state = await synthesizeAdvisorState();
+  expect(state).toContain("ADVISOR STATE UNAVAILABLE");
+});
+
+test("old complete (1h ago) is outside the completion window: no state", async () => {
+  fixture({ "session-a": row({ sessionUUID: UUID_A, phase: "complete", updatedAt: iso(60 * MIN) }) });
+  const state = await synthesizeAdvisorState();
+  expect(state).toContain("ADVISOR STATE UNAVAILABLE");
+});
+
+test("stale live row (2h idle) is not guessable: no state", async () => {
+  fixture({ "session-a": row({ sessionUUID: UUID_A, updatedAt: iso(120 * MIN) }) });
+  const state = await synthesizeAdvisorState();
+  expect(state).toContain("ADVISOR STATE UNAVAILABLE");
+});
+
+test("native placeholder rows are never candidates", async () => {
+  fixture({
+    "session-native": row({ sessionUUID: UUID_B, mode: "native", phase: "native" }),
+    "session-a": row({ sessionUUID: UUID_A }),
+  });
+  const state = await synthesizeAdvisorState();
+  expect(state).toContain("ISA: session-a");
+});
diff --git a/LifeOS/install/LIFEOS/TOOLS/Inference.ts b/LifeOS/install/LIFEOS/TOOLS/Inference.ts
index f13b5cea0a..67b286efdf 100755
--- a/LifeOS/install/LIFEOS/TOOLS/Inference.ts
+++ b/LifeOS/install/LIFEOS/TOOLS/Inference.ts
@@ -408,10 +408,31 @@ export async function inference(options: InferenceOptions): Promise<InferenceRes
  * that might have missed the problem decides what the reviewer sees. Auto-synthesis
  * reads the ISA directly so the reviewer gets the unfiltered state.
  *
- * Reads:
- * - Current ISA content (resolved from MEMORY/STATE/work.json active session, or
- *   the most recently-updated ISA in MEMORY/WORK/)
- * - Recent session activity if available
+ * Session resolution (deterministic, fail-safe):
+ * - work.json is a `{sessions: {...}}` registry. The pre-fix code looked for
+ *   `active`/`current`/`activeSession` keys that never existed, so it ALWAYS
+ *   fell through to "most recently modified dir in MEMORY/WORK/" — usually
+ *   right by accident, but with no session identity it could attach an
+ *   unrelated (often completed) session's ISA as the advisor state blob.
+ * - Resolution order:
+ *   1. Row matching CLAUDE_SESSION_ID, any phase — a phase:complete row of
+ *      the SAME session is still this session, and the advisor fires at the
+ *      completion boundary itself. Env set but unmatched → no state (never
+ *      fall through to a guess). Claude Code does not export
+ *      CLAUDE_SESSION_ID to tool subprocesses today; this path is
+ *      forward-looking defense-in-depth, local-trust only — not an auth
+ *      boundary.
+ *   2. No env: a COMPLETE row updated within the last 5 minutes is almost
+ *      certainly the just-finished caller making its mandatory
+ *      completion-boundary advisor call — prefer the most recent such row,
+ *      UNLESS any fresh live row also exists (then we cannot tell which
+ *      session is calling → ambiguous → no state).
+ *   3. No env, no recent-complete: exactly ONE live (non-complete,
+ *      non-native) row updated within the last 60 minutes → use it. Rows
+ *      idle longer are crash leftovers (the registry stale sweep only
+ *      prunes them after ~7 days) and are never guessable.
+ *   4. Anything else → return a state-unavailable marker and warn loudly.
+ *      Wrong state is worse than no state for a reviewer.
  *
  * Returns a state string suitable for passing to advisor().
  */
@@ -422,35 +443,75 @@ export async function synthesizeAdvisorState(): Promise<string> {
   const workDir = path.join(home, ".claude", "LIFEOS", "MEMORY", "WORK");
   const stateFile = path.join(home, ".claude", "LIFEOS", "MEMORY", "STATE", "work.json");
 
-  // Try to read active session from work.json
+  // Resolve the current session's slug from the work.json sessions registry.
   let activeSlug: string | undefined;
+  let sessions: Record<string, any> = {};
   try {
     const stateRaw = await fs.readFile(stateFile, "utf-8");
-    const state = JSON.parse(stateRaw);
-    activeSlug = state?.active || state?.current || state?.activeSession;
+    sessions = JSON.parse(stateRaw)?.sessions ?? {};
   } catch {
-    // work.json may not exist — fall back to most recent ISA
+    // work.json missing/unreadable — handled below as zero candidates.
   }
 
-  // Fall back: find most recently updated ISA in WORK/
+  const rows = Object.entries(sessions).filter(([slug]) => slug !== "__pulse_strip");
+  const updatedMs = (s: any) => {
+    const t = new Date(s?.updatedAt || s?.started || 0).getTime();
+    return Number.isFinite(t) ? t : 0;
+  };
+  const nowMs = Date.now();
+  // Freshness horizons — see the resolution-order doc comment above.
+  const LIVE_FRESH_MS = 60 * 60 * 1000;
+  const COMPLETE_RECENT_MS = 5 * 60 * 1000;
+
+  const unavailable = (detail: string): string => {
+    const warning =
+      `advisor --auto-state could not resolve the current session deterministically (${detail}); ` +
+      `proceeding WITHOUT auto-synthesized state. Pass explicit state or set CLAUDE_SESSION_ID.`;
+    console.error(`WARN: ${warning}`);
+    return `ADVISOR STATE UNAVAILABLE: ${warning}`;
+  };
+
+  // 1. Current session wins: row whose sessionUUID matches CLAUDE_SESSION_ID.
+  // A phase:complete row still belongs to THIS session, so it stays eligible;
+  // live rows are preferred, most recently updated breaks ties. Set-but-
+  // unmatched never falls through to a guess.
+  const envUUID = process.env.CLAUDE_SESSION_ID;
+  if (envUUID) {
+    const mine = rows
+      .filter(([, s]) => s?.sessionUUID === envUUID)
+      .sort((a, b) =>
+        (Number(a[1]?.phase === "complete") - Number(b[1]?.phase === "complete"))
+        || updatedMs(b[1]) - updatedMs(a[1]));
+    if (mine.length === 0) {
+      return unavailable(`CLAUDE_SESSION_ID matches no session row in work.json`);
+    }
+    activeSlug = mine[0][0];
+  }
+
+  // 2/3. No env: completion-boundary path first, then the single-fresh-live
+  // convenience path; anything else proceeds with NO state rather than guess.
   if (!activeSlug) {
-    try {
-      const entries = await fs.readdir(workDir, { withFileTypes: true });
-      const dirs = entries.filter((e) => e.isDirectory()).map((e) => e.name);
-      if (dirs.length === 0) {
-        return "No active ISA found. Advisor state unavailable.";
-      }
-      // Sort by mtime
-      const statted = await Promise.all(
-        dirs.map(async (d) => {
-          const s = await fs.stat(path.join(workDir, d));
-          return { name: d, mtime: s.mtimeMs };
-        }),
-      );
-      statted.sort((a, b) => b.mtime - a.mtime);
-      activeSlug = statted[0].name;
-    } catch (err) {
-      return `Unable to locate active ISA: ${(err as Error).message}`;
+    const live = rows.filter(([, s]) =>
+      s?.phase && s.phase !== "complete" && s.phase !== "native"
+      && nowMs - updatedMs(s) <= LIVE_FRESH_MS);
+    const recentComplete = rows
+      .filter(([, s]) => s?.phase === "complete" && nowMs - updatedMs(s) <= COMPLETE_RECENT_MS)
+      .sort((a, b) => updatedMs(b[1]) - updatedMs(a[1]));
+
+    if (recentComplete.length > 0 && live.length > 0) {
+      return unavailable(
+        `both just-completed [${recentComplete.map(([slug]) => slug).join(", ")}] and live ` +
+        `[${live.map(([slug]) => slug).join(", ")}] sessions exist — cannot tell which is calling`);
+    }
+    if (recentComplete.length > 0) {
+      activeSlug = recentComplete[0][0];
+    } else if (live.length === 1) {
+      activeSlug = live[0][0];
+    } else {
+      const detail = live.length === 0
+        ? "no live session rows in work.json (rows idle >60min are not guessable)"
+        : `${live.length} live sessions [${live.map(([slug]) => slug).join(", ")}]`;
+      return unavailable(detail);
     }
   }