The doc comment says the reject planApproval variant has optional feedback, but the schema below makes feedback required (minLength: 1). Update the per-variant requirements bullet to match the actual contract so clients don't implement against the wrong semantics.

This import points at ../../agents/pi-embedded-runner/pending-injection.js, but there is no pending-injection module under src/agents/pi-embedded-runner/ in the repo. As-is, this will fail build/tsc at module resolution time. Add the missing module (with these exports) or update the import to the correct existing file.

PLAN_MODE_REFERENCE_CARD is imported from ../../plan-mode/reference-card.js, but there is no src/agents/plan-mode/reference-card.ts/js in this PR/repo. This will fail module resolution at build time. Either add the missing reference-card module or remove/replace this import (and the usage) with an existing source.

createPlanModeStatusTool is imported from ./tools/plan-mode-status-tool.js, but there is no corresponding module under src/agents/tools/ in the repo. This will fail compilation/module resolution. Add the missing tool implementation file (and ensure it's exported/registered appropriately), or remove the import/usage if it was not meant to land in this slice.

PLAN_MODE_ALLOWED_TOOLS omits newly introduced plan-mode tools (e.g. ask_user_question, enter_plan_mode, plan_mode_status). Because this gate is default-deny, those tool calls will be blocked while planMode is active, breaking the intended plan-mode interactions. Add the missing tool names to the allowlist (and add/adjust mutation-gate tests to cover them).

New plan-mode error codes missing from error-codes.ts

ErrorCodes.PLAN_APPROVAL_EXPIRED (line 798) and ErrorCodes.PLAN_APPROVAL_GATE_STATE_UNAVAILABLE (line 850) access keys that don't exist on the ErrorCodes const object — they evaluate to undefined at runtime. Because invalid() uses code ?? ErrorCodes.INVALID_REQUEST, both calls silently fall back to "INVALID_REQUEST". Client code that branches on these specific codes (e.g. the "auto-dismiss stale approval card" logic described in the inline comment for PLAN_APPROVAL_EXPIRED) will never match and the intended UX behaviour is permanently suppressed.

The two string-literal forms on lines 879 and 890 ("PLAN_APPROVAL_BLOCKED_BY_SUBAGENTS", "PLAN_APPROVAL_WAITING_FOR_SUBAGENT_SETTLE") survive at runtime but are TypeScript type errors because they are not assignable to ErrorCode.

All four codes need to be added to src/gateway/protocol/schema/error-codes.ts:

export const ErrorCodes = {
  // ... existing codes ...
  PLAN_APPROVAL_EXPIRED: "PLAN_APPROVAL_EXPIRED",
  PLAN_APPROVAL_GATE_STATE_UNAVAILABLE: "PLAN_APPROVAL_GATE_STATE_UNAVAILABLE",
  PLAN_APPROVAL_BLOCKED_BY_SUBAGENTS: "PLAN_APPROVAL_BLOCKED_BY_SUBAGENTS",
  PLAN_APPROVAL_WAITING_FOR_SUBAGENT_SETTLE: "PLAN_APPROVAL_WAITING_FOR_SUBAGENT_SETTLE",
} as const;

Then replace the two string literals in sessions-patch.ts with ErrorCodes.* references for consistency.

This is a comment left during a code review.
Path: src/gateway/sessions-patch.ts
Line: 798

Comment:
**New plan-mode error codes missing from `error-codes.ts`**

`ErrorCodes.PLAN_APPROVAL_EXPIRED` (line 798) and `ErrorCodes.PLAN_APPROVAL_GATE_STATE_UNAVAILABLE` (line 850) access keys that don't exist on the `ErrorCodes` const object — they evaluate to `undefined` at runtime. Because `invalid()` uses `code ?? ErrorCodes.INVALID_REQUEST`, both calls silently fall back to `"INVALID_REQUEST"`. Client code that branches on these specific codes (e.g. the "auto-dismiss stale approval card" logic described in the inline comment for `PLAN_APPROVAL_EXPIRED`) will never match and the intended UX behaviour is permanently suppressed.

The two string-literal forms on lines 879 and 890 (`"PLAN_APPROVAL_BLOCKED_BY_SUBAGENTS"`, `"PLAN_APPROVAL_WAITING_FOR_SUBAGENT_SETTLE"`) survive at runtime but are TypeScript type errors because they are not assignable to `ErrorCode`.

All four codes need to be added to `src/gateway/protocol/schema/error-codes.ts`:

```typescript
export const ErrorCodes = {
  // ... existing codes ...
  PLAN_APPROVAL_EXPIRED: "PLAN_APPROVAL_EXPIRED",
  PLAN_APPROVAL_GATE_STATE_UNAVAILABLE: "PLAN_APPROVAL_GATE_STATE_UNAVAILABLE",
  PLAN_APPROVAL_BLOCKED_BY_SUBAGENTS: "PLAN_APPROVAL_BLOCKED_BY_SUBAGENTS",
  PLAN_APPROVAL_WAITING_FOR_SUBAGENT_SETTLE: "PLAN_APPROVAL_WAITING_FOR_SUBAGENT_SETTLE",
} as const;
```

Then replace the two string literals in `sessions-patch.ts` with `ErrorCodes.*` references for consistency.

How can I resolve this? If you propose a fix, please make it concise.

ask_user_question blocked by default-deny during plan mode

ask_user_question is not in PLAN_MODE_ALLOWED_TOOLS and does not match any suffix pattern, so the mutation gate's fail-through default deny blocks it whenever planMode === "plan". The tool's own description explicitly states "Plan-mode safety: questions DO NOT exit plan mode. The session stays in plan mode while waiting" — but an agent in plan mode calling ask_user_question will receive Tool "ask_user_question" is not in the plan-mode allowlist and is blocked by default before any question reaches the user.

enter_plan_mode has the same omission (calling it again while already in plan mode should not be blocked).

This is a comment left during a code review.
Path: src/agents/plan-mode/mutation-gate.ts
Line: 41-50

Comment:
**`ask_user_question` blocked by default-deny during plan mode**

`ask_user_question` is not in `PLAN_MODE_ALLOWED_TOOLS` and does not match any suffix pattern, so the mutation gate's fail-through default deny blocks it whenever `planMode === "plan"`. The tool's own description explicitly states "Plan-mode safety: questions DO NOT exit plan mode. The session stays in plan mode while waiting" — but an agent in plan mode calling `ask_user_question` will receive `Tool "ask_user_question" is not in the plan-mode allowlist and is blocked by default` before any question reaches the user.

`enter_plan_mode` has the same omission (calling it again while already in plan mode should not be blocked).

```suggestion
const PLAN_MODE_ALLOWED_TOOLS = new Set([
  "read",
  "web_search",
  "web_fetch",
  "memory_search",
  "memory_get",
  "update_plan",
  "exit_plan_mode",
  "ask_user_question",
  "enter_plan_mode",
  "session_status",
]);
```

How can I resolve this? If you propose a fix, please make it concise.

Wire subagent gate persistence before approval gating

The subagent approval gate relies on persisted blockingSubagentRunIds when the parent run context is gone, but this persistence path is effectively disabled: persistPlanModeSubagentGateState exits immediately when no handler is set, and I could not find any call site that registers setPlanModeSubagentGatePersistenceHandler in the repo. In the common flow where clearAgentRunContext(runId) runs before a delayed approval arrives, the gate in sessions-patch.ts can see an empty persisted set and allow approve/edit even though subagents are still running. Please register the persistence handler during gateway/session-store initialization (or fail closed when persistence is unavailable).

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Permit verifiedCriteria-only deltas in merge mode

This validation rejects any step update that includes verifiedCriteria without also resending acceptanceCriteria. That breaks the intended incremental merge workflow (marking criteria as verified over time) because callers must echo the full acceptance list on every update, and a normal delta like merge: true + updated verifiedCriteria against an existing step is rejected before merge. Validate verifiedCriteria against the merged step's acceptance criteria (existing + incoming) instead of requiring acceptanceCriteria in every delta payload.

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