diff --git a/packages/jimmy/src/cron/__tests__/runner.test.ts b/packages/jimmy/src/cron/__tests__/runner.test.ts
index 9b001e6b9..ecc62ab5f 100644
--- a/packages/jimmy/src/cron/__tests__/runner.test.ts
+++ b/packages/jimmy/src/cron/__tests__/runner.test.ts
@@ -340,3 +340,134 @@ describe("runCronJob — session ended in error without route() throwing", () =>
     expect(opsAlert).not.toHaveBeenCalled();
   });
 });
+
+describe("runCronJob — session killed by the wall-clock timeout", () => {
+  // Regression for the Aug-2026 steward finding: sessions.maxDurationMinutes
+  // killed the engine, the manager flattened the kill to status:"idle" +
+  // lastError:null, and the runner logged {"status":"success","error":null}
+  // with no delivery and no alert. 75 runs across ~20 jobs went dark that way —
+  // including the system-steward audit itself, which failed 2/2 months while
+  // its run history read "success" both times.
+  beforeEach(async () => {
+    const { opsAlert } = await import("../../shared/ops-alert.js");
+    const { appendRunLog } = await import("../jobs.js");
+    const { getSession } = await import("../../sessions/registry.js");
+    (opsAlert as any).mockReset().mockResolvedValue(undefined);
+    (appendRunLog as any).mockClear();
+    (getSession as any).mockReset().mockReturnValue(undefined);
+  });
+
+  const timedOutSession = (overrides = {}) => ({
+    status: "interrupted",
+    lastError: "Interrupted: session timeout (45m)",
+    totalTurns: 137,
+    ...overrides,
+  });
+
+  it("logs status 'session_timeout' carrying the reason, not 'success'", async () => {
+    const { appendRunLog } = await import("../jobs.js");
+    const { getSession } = await import("../../sessions/registry.js");
+    (getSession as any).mockReturnValue(timedOutSession());
+
+    const sessionManager = makeMockSessionManager(0);
+    const connectors = new Map<string, Connector>([["slack", makeMockConnector()]]);
+
+    await runCronJob(makeJob(), sessionManager, makeConfig(), connectors);
+
+    expect(appendRunLog).toHaveBeenCalledWith(
+      "test-job",
+      expect.objectContaining({
+        status: "session_timeout",
+        error: "Interrupted: session timeout (45m)",
+        actualTurns: 137,
+      }),
+    );
+  });
+
+  it("fires an ops-alert naming the timeout", async () => {
+    const { opsAlert } = await import("../../shared/ops-alert.js");
+    const { getSession } = await import("../../sessions/registry.js");
+    (getSession as any).mockReturnValue(timedOutSession());
+
+    const sessionManager = makeMockSessionManager(0);
+    const connectors = new Map<string, Connector>([["slack", makeMockConnector()]]);
+
+    await runCronJob(makeJob(), sessionManager, makeConfig(), connectors);
+
+    expect(opsAlert).toHaveBeenCalledTimes(1);
+    const msg = (opsAlert as any).mock.calls[0][0];
+    expect(msg).toContain("FAILED");
+    expect(msg).toMatch(/wall-clock/i);
+  });
+
+  it("warns about partial writes when the job is flagged sideEffects", async () => {
+    const { opsAlert } = await import("../../shared/ops-alert.js");
+    const { getSession } = await import("../../sessions/registry.js");
+    (getSession as any).mockReturnValue(timedOutSession());
+
+    const sessionManager = makeMockSessionManager(0);
+    const connectors = new Map<string, Connector>([["slack", makeMockConnector()]]);
+
+    await runCronJob(
+      makeJob({ sessionBudget: { sideEffects: true } }),
+      sessionManager,
+      makeConfig(),
+      connectors,
+    );
+
+    expect((opsAlert as any).mock.calls[0][0]).toContain("partial external writes");
+  });
+
+  it("does NOT also fire the latency alert (single alert, no 🐢 on top)", async () => {
+    const { opsAlert } = await import("../../shared/ops-alert.js");
+    const { getSession } = await import("../../sessions/registry.js");
+    (getSession as any).mockReturnValue(timedOutSession());
+
+    const connector = makeMockConnector();
+    const connectors = new Map<string, Connector>([["slack", connector]]);
+    // 200ms run against a 100ms threshold would normally trip the latency alert
+    const sessionManager = makeMockSessionManager(200);
+
+    await runCronJob(makeJob(), sessionManager, makeConfig({ alertThresholdMs: 100 }), connectors);
+
+    expect(opsAlert).toHaveBeenCalledTimes(1);
+    expect(connector.sendMessage).not.toHaveBeenCalled();
+  });
+
+  it("catches the engine-never-started timeout shape too", async () => {
+    const { appendRunLog } = await import("../jobs.js");
+    const { getSession } = await import("../../sessions/registry.js");
+    (getSession as any).mockReturnValue(
+      timedOutSession({ lastError: "Interrupted: session timeout (45m) — engine never started" }),
+    );
+
+    const sessionManager = makeMockSessionManager(0);
+    const connectors = new Map<string, Connector>([["slack", makeMockConnector()]]);
+
+    await runCronJob(makeJob(), sessionManager, makeConfig(), connectors);
+
+    expect(appendRunLog).toHaveBeenCalledWith(
+      "test-job",
+      expect.objectContaining({ status: "session_timeout" }),
+    );
+  });
+
+  it("does NOT classify a benign user interrupt as a timeout", async () => {
+    const { appendRunLog } = await import("../jobs.js");
+    const { opsAlert } = await import("../../shared/ops-alert.js");
+    const { getSession } = await import("../../sessions/registry.js");
+    // "Interrupted by user" / "new message received" stay silent successes
+    (getSession as any).mockReturnValue({ status: "idle", lastError: null, totalTurns: 4 });
+
+    const sessionManager = makeMockSessionManager(0);
+    const connectors = new Map<string, Connector>([["slack", makeMockConnector()]]);
+
+    await runCronJob(makeJob(), sessionManager, makeConfig(), connectors);
+
+    expect(appendRunLog).toHaveBeenCalledWith(
+      "test-job",
+      expect.objectContaining({ status: "success" }),
+    );
+    expect(opsAlert).not.toHaveBeenCalled();
+  });
+});
diff --git a/packages/jimmy/src/cron/runner.ts b/packages/jimmy/src/cron/runner.ts
index 14f7e2e97..eaae335d3 100644
--- a/packages/jimmy/src/cron/runner.ts
+++ b/packages/jimmy/src/cron/runner.ts
@@ -7,6 +7,7 @@ import { CronConnector } from "../connectors/cron/index.js";
 import type { SessionManager } from "../sessions/manager.js";
 import { resolveJobBudget, SESSION_BUDGET_STOP_PREFIX } from "../sessions/budget.js";
 import { getSession } from "../sessions/registry.js";
+import { SESSION_TIMEOUT_PREFIX } from "../shared/timeout.js";
 import { opsAlert } from "../shared/ops-alert.js";
 import { runPrecheck } from "./precheck.js";
 
@@ -174,19 +175,36 @@ export async function runCronJob(
     // Jun-2026 silent cron outage (a moved Claude binary ENOENT'd ~400 fires,
     // every one logged "completed in 16ms"). Treat a non-budget session error as
     // a cron failure: record it and fire an ops-alert.
-    const sessionErrored = !budgetStopped && finalSession?.status === "error";
+    // A session killed by the wall-clock cap (sessions.maxDurationMinutes) is
+    // ALSO not a success: the manager used to flatten it to status:"idle" with a
+    // null lastError, so it landed here as "success"/no-alert — 75 runs across
+    // ~20 jobs went dark that way, including this steward's own monthly audit
+    // failing 2/2 months while run-history read "success". The manager now
+    // preserves status:"interrupted" + the SESSION_TIMEOUT_PREFIX sentinel;
+    // classify it as a distinct failure so the reason survives into the run-log.
+    const timedOut = !budgetStopped && !!finalSession?.lastError?.startsWith(SESSION_TIMEOUT_PREFIX);
+    const sessionErrored = !budgetStopped && !timedOut && finalSession?.status === "error";
     appendRunLog(job.id, {
       timestamp: startedAt,
       sessionKey,
       sessionId: routeResult?.sessionId ?? null,
-      status: budgetStopped ? "session_budget_stop" : sessionErrored ? "error" : "success",
+      status: budgetStopped
+        ? "session_budget_stop"
+        : timedOut
+          ? "session_timeout"
+          : sessionErrored
+            ? "error"
+            : "success",
       durationMs,
       error: budgetStopped
         ? finalSession?.lastError ?? null
-        : sessionErrored
-          ? finalSession?.lastError ?? "session ended in error"
-          : null,
+        : timedOut
+          ? finalSession?.lastError ?? "session hit the wall-clock timeout"
+          : sessionErrored
+            ? finalSession?.lastError ?? "session ended in error"
+            : null,
       ...(budgetStopped ? { maxTurns: budget.maxTurns, actualTurns: finalSession?.totalTurns ?? null } : {}),
+      ...(timedOut ? { actualTurns: finalSession?.totalTurns ?? null } : {}),
       ...catchUpFields,
       resultPreview: null,
     });
@@ -196,7 +214,19 @@ export async function runCronJob(
         `after ~${finalSession?.totalTurns ?? "?"} turns. This job is flagged sideEffects:true — check for partial external writes.`,
       ).catch(() => {});
     }
-    if (sessionErrored) {
+    if (timedOut) {
+      logger.error(
+        `Cron job "${job.name}" (${job.id}) hit the session wall-clock timeout after ${durationMs}ms: ${finalSession?.lastError ?? "(no message)"}`,
+      );
+      await opsAlert(
+        `Cron "${job.name}" (${job.id}) FAILED — killed by the session wall-clock cap after ` +
+          `${(durationMs / 60_000).toFixed(1)}min (~${finalSession?.totalTurns ?? "?"} turns). No reply was delivered. ` +
+          `${finalSession?.lastError?.slice(0, 200) ?? ""}` +
+          (budget.sideEffects
+            ? " This job is flagged sideEffects:true — check for partial external writes."
+            : " Raise sessions.maxDurationMinutes or trim the job's scope."),
+      ).catch(() => {});
+    } else if (sessionErrored) {
       logger.error(
         `Cron job "${job.name}" (${job.id}) session ended in error in ${durationMs}ms: ${finalSession?.lastError ?? "(no message)"}`,
       );
@@ -208,9 +238,11 @@ export async function runCronJob(
       logger.info(`Cron job "${job.name}" ${budgetStopped ? "stopped at turn budget" : "completed"} in ${durationMs}ms`);
     }
 
-    // Latency alert: warn if job exceeded threshold
+    // Latency alert: warn if job exceeded threshold. Skipped on a timeout — a
+    // wall-clock kill always blows past the latency threshold, and the failure
+    // alert above already carries the duration; a 🐢 on top is pure noise.
     const thresholdMs = config.cron?.alertThresholdMs;
-    if (thresholdMs && durationMs > thresholdMs) {
+    if (thresholdMs && durationMs > thresholdMs && !timedOut) {
       const alertConnector = config.cron?.alertConnector;
       const alertChannel = config.cron?.alertChannel;
       if (alertConnector && alertChannel) {
diff --git a/packages/jimmy/src/gateway/api.ts b/packages/jimmy/src/gateway/api.ts
index a45e8261b..6ce03495c 100644
--- a/packages/jimmy/src/gateway/api.ts
+++ b/packages/jimmy/src/gateway/api.ts
@@ -6,7 +6,7 @@ import path from "node:path";
 import yaml from "js-yaml";
 import type { CronJob, Engine, IncomingMessage, JinnConfig, Session, Target } from "../shared/types.js";
 import { isInterruptibleEngine } from "../shared/types.js";
-import { startSessionTimeout } from "../shared/timeout.js";
+import { startSessionTimeout, SESSION_TIMEOUT_PREFIX } from "../shared/timeout.js";
 import type { SessionManager } from "../sessions/manager.js";
 import { buildContext } from "../sessions/context.js";
 import {
@@ -2541,6 +2541,9 @@ async function runWebSession(
     }
 
     const wasInterrupted = result.error?.startsWith("Interrupted");
+    // Same carve-out as SessionManager.runSession: a wall-clock timeout kill is
+    // not a benign interrupt and must not be flattened to a clean idle row.
+    const timedOut = !!result.error?.startsWith(SESSION_TIMEOUT_PREFIX);
     const rateLimit = !wasInterrupted ? detectRateLimit(result) : { limited: false as const };
 
     if (rateLimit.limited) {
@@ -2835,9 +2838,9 @@ async function runWebSession(
 
     const completedSession = updateSession(currentSession.id, {
       ...(result.sessionId?.trim() ? { engineSessionId: result.sessionId } : {}),
-      status: wasInterrupted ? "idle" : (result.error ? "error" : "idle"),
+      status: timedOut ? "interrupted" : wasInterrupted ? "idle" : (result.error ? "error" : "idle"),
       lastActivity: new Date().toISOString(),
-      lastError: wasInterrupted ? null : (result.error ?? null),
+      lastError: timedOut ? (result.error ?? null) : (wasInterrupted ? null : (result.error ?? null)),
     });
     if (result.cost || result.numTurns) {
       try {
diff --git a/packages/jimmy/src/sessions/manager.ts b/packages/jimmy/src/sessions/manager.ts
index a1f151622..2de84b481 100644
--- a/packages/jimmy/src/sessions/manager.ts
+++ b/packages/jimmy/src/sessions/manager.ts
@@ -10,7 +10,7 @@ import type {
   Target,
 } from "../shared/types.js";
 import { modelFor } from "../shared/types.js";
-import { startSessionTimeout } from "../shared/timeout.js";
+import { startSessionTimeout, sessionTimeoutReason, SESSION_TIMEOUT_PREFIX } from "../shared/timeout.js";
 import {
   accumulateSessionCost,
   logSessionCost,
@@ -378,7 +378,9 @@ export class SessionManager {
         source: session.source,
         onForceInterrupt: () => updateSession(session.id, {
           status: "interrupted",
-          lastError: `Session timeout (${timeoutMinutes}m) — engine never started`,
+          // Same sentinel prefix as the live-engine kill, so the cron runner
+          // classifies both timeout shapes identically.
+          lastError: `${sessionTimeoutReason(Number(timeoutMinutes))} — engine never started`,
         }),
       });
 
@@ -505,6 +507,11 @@ export class SessionManager {
       }
 
       const wasInterrupted = result.error?.startsWith("Interrupted");
+      // A wall-clock timeout kill is NOT a benign interrupt. "Interrupted by
+      // user"/"new message received" are expected and must stay silent, but the
+      // maxDurationMinutes kill means the task died mid-flight — it has to
+      // survive into the session row so the cron runner can classify the run.
+      const timedOut = !!result.error?.startsWith(SESSION_TIMEOUT_PREFIX);
 
       // Dead session detection: if the engine session ID is stale (expired/invalid),
       // clear cached engine sessions from transportMeta so the next attempt starts fresh.
@@ -935,7 +942,7 @@ export class SessionManager {
       }
       const updatedSession = updateSession(session.id, {
         ...(result.sessionId?.trim() ? { engineSessionId: result.sessionId } : {}),
-        status: wasInterrupted ? "idle" : (result.error ? "error" : "idle"),
+        status: timedOut ? "interrupted" : wasInterrupted ? "idle" : (result.error ? "error" : "idle"),
         replyContext: msg.replyContext,
         messageId: msg.messageId ?? null,
         transportMeta: (() => {
@@ -946,10 +953,10 @@ export class SessionManager {
           return merged as any;
         })(),
         lastActivity: new Date().toISOString(),
-        lastError: wasInterrupted ? null : (result.error ?? null),
+        lastError: timedOut ? (result.error ?? null) : (wasInterrupted ? null : (result.error ?? null)),
       });
       if (updatedSession) {
-        notifyParentSession(updatedSession, { result: result.result, error: wasInterrupted ? null : (result.error ?? null), cost: result.cost, durationMs: result.durationMs }, { alwaysNotify: employee?.alwaysNotify });
+        notifyParentSession(updatedSession, { result: result.result, error: (timedOut || !wasInterrupted) ? (result.error ?? null) : null, cost: result.cost, durationMs: result.durationMs }, { alwaysNotify: employee?.alwaysNotify });
       }
 
       logger.info(
diff --git a/packages/jimmy/src/shared/timeout.ts b/packages/jimmy/src/shared/timeout.ts
index b19218c80..d3d0423a3 100644
--- a/packages/jimmy/src/shared/timeout.ts
+++ b/packages/jimmy/src/shared/timeout.ts
@@ -2,6 +2,19 @@ import type { Engine } from "./types.js";
 import { isInterruptibleEngine } from "./types.js";
 import { logger } from "./logger.js";
 
+/** Sentinel prefix for the kill reason written when the wall-clock cap fires.
+ *  Still begins with "Interrupted" so the engines' retry-skip and the session
+ *  manager's `startsWith("Interrupted")` idiom keep working, but is specific
+ *  enough that both the manager and the cron runner can tell a TIMEOUT kill
+ *  apart from a benign user interrupt ("Interrupted by user", "Interrupted:
+ *  new message received"). Mirrors SESSION_BUDGET_STOP_PREFIX. */
+export const SESSION_TIMEOUT_PREFIX = "Interrupted: session timeout";
+
+/** The exact kill reason for a wall-clock timeout at `minutes`. */
+export function sessionTimeoutReason(minutes: number): string {
+  return `${SESSION_TIMEOUT_PREFIX} (${minutes}m)`;
+}
+
 /**
  * Start a session timeout that kills the engine after `timeoutMinutes`.
  * Returns the timer handle (for clearTimeout in finally), or undefined if no timeout was set.
@@ -31,7 +44,7 @@ export function startSessionTimeout(
   return setTimeout(() => {
     const wasAlive = engine.isAlive(sessionId);
     logger.info(`Session ${label} exceeded ${capped}m timeout — killing engine`);
-    engine.kill(sessionId, `Interrupted: session timeout (${capped}m)`);
+    engine.kill(sessionId, sessionTimeoutReason(capped));
     if (!wasAlive) {
       logger.warn(`Session ${label} has no live engine process — marking interrupted`);
       opts?.onForceInterrupt?.();