diff --git a/packages/engine/src/__tests__/reliability-interactions/mission-validation-trigger-gap.test.ts b/packages/engine/src/__tests__/reliability-interactions/mission-validation-trigger-gap.test.ts
index fe3064af9..2cbfdb9ba 100644
--- a/packages/engine/src/__tests__/reliability-interactions/mission-validation-trigger-gap.test.ts
+++ b/packages/engine/src/__tests__/reliability-interactions/mission-validation-trigger-gap.test.ts
@@ -215,6 +215,11 @@ describe("FN-5715 reliability: mission validation trigger gap", () => {
       completeValidatorRun: vi.fn(),
       getSlice: vi.fn(() => ({ id: "SL-001", milestoneId: "MS-001", status: "active" })),
       getMilestone: vi.fn(() => ({ id: "MS-001", missionId: "M-001" })),
+      // resolveFeatureMission (reached via processTaskOutcome during recovery)
+      // walks getSlice → getMilestone → getMission to gate on mission.status.
+      // Without getMission the walk throws and recovery aborts before it can
+      // ensure assertions / start the validator run this test asserts on.
+      getMission: vi.fn(() => ({ id: "M-001", status: "active" })),
       logMissionEvent: vi.fn(),
       transitionLoopState: vi.fn(),
       setFeatureCurrentTaskRunId: vi.fn(),
@@ -277,6 +282,11 @@ describe("FN-5715 reliability: mission validation trigger gap", () => {
       completeValidatorRun: vi.fn(),
       getSlice: vi.fn(() => ({ id: "SL-001", milestoneId: "MS-001", status: "active" })),
       getMilestone: vi.fn(() => ({ id: "MS-001", missionId: "M-001" })),
+      // resolveFeatureMission (reached via processTaskOutcome during recovery)
+      // walks getSlice → getMilestone → getMission to gate on mission.status.
+      // Without getMission the walk throws and recovery aborts before it can
+      // ensure assertions / start the validator run this test asserts on.
+      getMission: vi.fn(() => ({ id: "M-001", status: "active" })),
       logMissionEvent: vi.fn(),
       transitionLoopState: vi.fn(),
       setFeatureCurrentTaskRunId: vi.fn(),
diff --git a/packages/engine/src/__tests__/restart.integration.test.ts b/packages/engine/src/__tests__/restart.integration.test.ts
index 3bc7b31f1..285891d26 100644
--- a/packages/engine/src/__tests__/restart.integration.test.ts
+++ b/packages/engine/src/__tests__/restart.integration.test.ts
@@ -43,6 +43,12 @@ vi.mock("../pi.js", () => ({
   // session. The mock must expose the export so the resume/triage paths can
   // reach finalization instead of throwing on a missing mock member.
   formatModelMarkerDetails: vi.fn((model: string) => model),
+  // triage.ts guards its catch block with `err instanceof ModelFallbackExhaustedError`
+  // (imported from pi.js). Because this factory replaces pi.js wholesale, the class
+  // must be exported or evaluating the `instanceof` throws "No ModelFallbackExhaustedError
+  // export is defined on the mock". No restart test enters the fallback-exhausted branch,
+  // so a plain Error subclass is a faithful stub (instanceof simply returns false).
+  ModelFallbackExhaustedError: class ModelFallbackExhaustedError extends Error {},
 }));
 vi.mock("../reviewer.js", () => ({
   reviewStep: vi.fn(),