feat(approvals): reject-with-reason — relay an optional decline reason to the agent

Add a third "Reject with reason…" button to module approval cards. Plain
Reject stays the instant fast path; the new option holds the row
(status='awaiting_reason'), DM-prompts the approver, and captures their
next DM (≤280 chars, truncated) as a one-line reason relayed to the
requesting agent as a single combined message. A ghosted hold is
finalized as a plain reject by the host sweep after ~5 min — restart-safe
via the durable DB row.

- Generalize the router message-interceptor to a list
  (registerMessageInterceptor) so approvals can capture replies alongside
  the permissions agent-naming flow.
- Share reject finalization across the instant, captured, and swept paths
  via finalizeReject.
- Scope: all module approvals (create_agent, install_packages,
  add_mcp_server); OneCLI credential cards are unchanged.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/db/sessions.ts

@@ -184,6 +184,28 @@ export function updatePendingApprovalStatus(approvalId: string, status: PendingA
   getDb().prepare('UPDATE pending_approvals SET status = ? WHERE approval_id = ?').run(status, approvalId);
 }
 
+/**
+ * Park an approval in the "rejected, awaiting reason" hold: the admin clicked
+ * "Reject with reason…" and we're waiting for their one-line reply. `expiresAt`
+ * is the deadline after which the host sweep finalizes a plain reject (so a
+ * ghosted hold never strands the requesting agent). Reuses the otherwise-unused
+ * `expires_at` column on module-initiated rows.
+ */
+export function markApprovalAwaitingReason(approvalId: string, expiresAt: string): void {
+  getDb()
+    .prepare("UPDATE pending_approvals SET status = 'awaiting_reason', expires_at = ? WHERE approval_id = ?")
+    .run(expiresAt, approvalId);
+}
+
+/** Awaiting-reason approvals whose reply window has elapsed — the sweep's ghost set. */
+export function getExpiredAwaitingReasonApprovals(nowIso: string): PendingApproval[] {
+  return getDb()
+    .prepare(
+      "SELECT * FROM pending_approvals WHERE status = 'awaiting_reason' AND expires_at IS NOT NULL AND expires_at <= ?",
+    )
+    .all(nowIso) as PendingApproval[];
+}
+
 export function deletePendingApproval(approvalId: string): void {
   getDb().prepare('DELETE FROM pending_approvals WHERE approval_id = ?').run(approvalId);
 }

src/host-sweep.ts

@@ -152,6 +152,18 @@ async function sweep(): Promise<void> {
     log.error('Host sweep error', { err });
   }
 
+  // Finalize any "Reject with reason…" holds whose reply window elapsed (admin
+  // ghosted, or the host restarted mid-capture). Central-DB scan, once per tick
+  // — not per session.
+  // MODULE-HOOK:approvals-reason-sweep:start
+  try {
+    const { sweepAwaitingReasonRejects } = await import('./modules/approvals/index.js');
+    await sweepAwaitingReasonRejects();
+  } catch (err) {
+    log.error('Reject-with-reason sweep failed', { err });
+  }
+  // MODULE-HOOK:approvals-reason-sweep:end
+
   setTimeout(sweep, SWEEP_INTERVAL_MS);
 }
 

src/modules/approvals/finalize.ts

@@ -0,0 +1,59 @@
+/**
+ * Shared "finalize a rejected approval" path.
+ *
+ * Three entry points land here so they relay one message and clean up
+ * identically:
+ *   1. The instant Reject button            (response-handler.ts)
+ *   2. A captured Reject-with-reason reply   (reason-capture.ts)
+ *   3. The host-sweep ghost finalizer        (reason-capture.ts, via host-sweep)
+ *
+ * Kept in its own leaf file so both response-handler.ts and reason-capture.ts
+ * can import it without an import cycle (finalize → primitive only).
+ */
+import { wakeContainer } from '../../container-runner.js';
+import { deletePendingApproval } from '../../db/sessions.js';
+import { log } from '../../log.js';
+import { writeSessionMessage } from '../../session-manager.js';
+import type { PendingApproval, Session } from '../../types.js';
+import { notifyApprovalResolved } from './primitive.js';
+
+/**
+ * Notify the requesting agent that its action was rejected, drop the pending
+ * row, fire approval-resolved callbacks, and wake the container.
+ *
+ * When `reason` is provided it's appended to the agent-facing note with generic
+ * attribution — the why, not the who (the rejecting admin may belong to a
+ * different owner than the requesting agent). Callers are responsible for
+ * clamping the reason length before passing it in.
+ */
+export async function finalizeReject(
+  approval: PendingApproval,
+  session: Session,
+  userId: string,
+  reason?: string,
+): Promise<void> {
+  const text = reason
+    ? `Your ${approval.action} request was rejected by admin: "${reason}"`
+    : `Your ${approval.action} request was rejected by admin.`;
+
+  writeSessionMessage(session.agent_group_id, session.id, {
+    id: `appr-note-${Date.now()}-${Math.random().toString(36).slice(2, 8)}`,
+    kind: 'chat',
+    timestamp: new Date().toISOString(),
+    platformId: session.agent_group_id,
+    channelType: 'agent',
+    threadId: null,
+    content: JSON.stringify({ text, sender: 'system', senderId: 'system' }),
+  });
+
+  log.info('Approval rejected', {
+    approvalId: approval.approval_id,
+    action: approval.action,
+    userId,
+    withReason: reason !== undefined,
+  });
+
+  deletePendingApproval(approval.approval_id);
+  await notifyApprovalResolved({ approval, session, outcome: 'reject', userId });
+  await wakeContainer(session);
+}

src/modules/approvals/index.ts

@@ -8,10 +8,16 @@
  *   - A response handler that claims pending_approvals rows and dispatches
  *     to whatever module registered for the row's `action` string. Also
  *     resolves in-memory OneCLI credential approvals.
+ *   - A message-interceptor (via ./reason-capture.js) that captures an admin's
+ *     one-line reply after they click "Reject with reason…".
  *   - An adapter-ready callback that starts the OneCLI manual-approval handler
  *     once the delivery adapter is set.
  *   - A shutdown callback that stops the OneCLI handler cleanly.
  *
+ * Exposes `sweepAwaitingReasonRejects` for the host sweep to finalize ghosted
+ * reject-with-reason holds (re-exported here, which also loads reason-capture
+ * so its interceptor registers).
+ *
  * Self-mod flows (install_packages, add_mcp_server) moved out to
  * `src/modules/self-mod/` in PR #7 — they now register delivery actions
  * + approval handlers via this module's public API.
@@ -24,6 +30,9 @@ import { startOneCLIApprovalHandler, stopOneCLIApprovalHandler } from './onecli-
 // Public API re-exports so consumers import from the module root.
 export { requestApproval, registerApprovalHandler, notifyAgent } from './primitive.js';
 export type { ApprovalHandler, ApprovalHandlerContext, RequestApprovalOptions } from './primitive.js';
+// Host-sweep hook for ghosted "Reject with reason…" holds. The re-export also
+// loads reason-capture.js, registering its message-interceptor on import.
+export { sweepAwaitingReasonRejects } from './reason-capture.js';
 
 registerResponseHandler(handleApprovalsResponse);
 

src/modules/approvals/primitive.ts

@@ -32,10 +32,23 @@ import type { MessagingGroup, PendingApproval, Session } from '../../types.js';
 import { getAdminsOfAgentGroup, getGlobalAdmins, getOwners } from '../permissions/db/user-roles.js';
 import { ensureUserDm } from '../permissions/user-dm.js';
 
-/** Two-button approval UI — the only options the primitive supports today. */
+/**
+ * Card value for the "Reject with reason…" button. Selecting it doesn't
+ * finalize the reject — it holds the row and captures the approver's next DM
+ * as a one-line reason relayed to the requesting agent. See reason-capture.ts.
+ */
+export const REJECT_WITH_REASON_VALUE = 'reject_with_reason';
+
+/**
+ * Three-button approval UI. Plain Reject is the instant fast path; "Reject with
+ * reason…" opts into the reason-capture flow. Shared by every module approval
+ * (create_agent, install_packages, add_mcp_server); OneCLI credential cards
+ * keep their own two-button set in onecli-approvals.ts.
+ */
 const APPROVAL_OPTIONS: RawOption[] = [
   { label: 'Approve', selectedLabel: '✅ Approved', value: 'approve' },
   { label: 'Reject', selectedLabel: '❌ Rejected', value: 'reject' },
+  { label: 'Reject with reason…', selectedLabel: '📝 Rejected (awaiting reason)', value: REJECT_WITH_REASON_VALUE },
 ];
 
 // ── Approval handler registry ──

src/modules/approvals/reason-capture.test.ts

@@ -0,0 +1,279 @@
+/**
+ * "Reject with reason…" capture flow.
+ *
+ * Covers the three entry points end to end against the real central DB:
+ *   - arming (handleApprovalsResponse with the third option) holds the row and
+ *     prompts the admin instead of finalizing;
+ *   - the captured reply relays one combined message, clamped to 280 chars;
+ *   - the host sweep finalizes a ghosted hold as a plain reject.
+ *
+ * writeSessionMessage is mocked so the relayed agent-facing text can be read
+ * back directly; the delivery adapter is a fake that records prompt sends.
+ */
+import * as fs from 'fs';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+
+import type { InboundEvent } from '../../channels/adapter.js';
+import { initTestDb, closeDb, runMigrations } from '../../db/index.js';
+import { createAgentGroup } from '../../db/agent-groups.js';
+import { createMessagingGroup } from '../../db/messaging-groups.js';
+import {
+  createSession,
+  createPendingApproval,
+  deletePendingApproval,
+  getPendingApproval,
+  markApprovalAwaitingReason,
+} from '../../db/sessions.js';
+import { setDeliveryAdapter, type ChannelDeliveryAdapter } from '../../delivery.js';
+import { writeSessionMessage } from '../../session-manager.js';
+import { upsertUser } from '../permissions/db/users.js';
+import { upsertUserDm } from '../permissions/db/user-dms.js';
+import { grantRole } from '../permissions/db/user-roles.js';
+import { REJECT_WITH_REASON_VALUE } from './primitive.js';
+
+vi.mock('../../container-runner.js', () => ({
+  wakeContainer: vi.fn().mockResolvedValue(undefined),
+}));
+
+vi.mock('../../config.js', async () => {
+  const actual = await vi.importActual('../../config.js');
+  return { ...actual, DATA_DIR: '/tmp/nanoclaw-test-reject-reason' };
+});
+
+vi.mock('../../session-manager.js', async () => {
+  const actual = await vi.importActual<typeof import('../../session-manager.js')>('../../session-manager.js');
+  return { ...actual, writeSessionMessage: vi.fn() };
+});
+
+const TEST_DIR = '/tmp/nanoclaw-test-reject-reason';
+const DM_CHANNEL = 'slack';
+const DM_PLATFORM = 'D-admin-1';
+
+function now(): string {
+  return new Date().toISOString();
+}
+
+let delivered: Array<{ channelType: string; platformId: string; content: string }>;
+
+const fakeAdapter: ChannelDeliveryAdapter = {
+  async deliver(channelType, platformId, _threadId, _kind, content) {
+    delivered.push({ channelType, platformId, content });
+    return 'pm-1';
+  },
+};
+
+function seedApproval(approvalId: string, action = 'create_agent'): void {
+  createPendingApproval({
+    approval_id: approvalId,
+    session_id: 'sess-1',
+    request_id: approvalId,
+    action,
+    payload: JSON.stringify({ name: 'child' }),
+    created_at: now(),
+    title: 'Approval',
+    options_json: JSON.stringify([]),
+  });
+}
+
+function dmReply(text?: string): InboundEvent {
+  const content: Record<string, unknown> = { sender: 'admin-1', senderId: 'admin-1' };
+  if (text !== undefined) content.text = text;
+  return {
+    channelType: DM_CHANNEL,
+    platformId: DM_PLATFORM,
+    threadId: null,
+    message: { id: 'm-1', kind: 'chat', content: JSON.stringify(content), timestamp: now() },
+  };
+}
+
+/** Click the "Reject with reason…" button as the seeded admin. */
+async function clickRejectWithReason(approvalId: string): Promise<void> {
+  const { handleApprovalsResponse } = await import('./response-handler.js');
+  await handleApprovalsResponse({
+    questionId: approvalId,
+    value: REJECT_WITH_REASON_VALUE,
+    userId: 'admin-1',
+    channelType: DM_CHANNEL,
+    platformId: '', // not surfaced by the click payload — resolved via ensureUserDm
+    threadId: null,
+  });
+}
+
+/** The text of the most recent agent-facing note written via writeSessionMessage. */
+function lastRelayedText(): string | undefined {
+  const call = vi.mocked(writeSessionMessage).mock.calls.at(-1);
+  if (!call) return undefined;
+  return (JSON.parse(call[2].content) as { text: string }).text;
+}
+
+beforeEach(() => {
+  vi.clearAllMocks();
+  if (fs.existsSync(TEST_DIR)) fs.rmSync(TEST_DIR, { recursive: true, force: true });
+  fs.mkdirSync(TEST_DIR, { recursive: true });
+  const db = initTestDb();
+  runMigrations(db);
+  delivered = [];
+
+  createAgentGroup({ id: 'ag-1', name: 'Agent', folder: 'agent', agent_provider: null, created_at: now() });
+  createSession({
+    id: 'sess-1',
+    agent_group_id: 'ag-1',
+    messaging_group_id: null,
+    thread_id: null,
+    agent_provider: null,
+    status: 'active',
+    container_status: 'stopped',
+    last_active: now(),
+    created_at: now(),
+  });
+
+  // Authorized approver + a cached DM so ensureUserDm resolves without a
+  // platform openDM call.
+  upsertUser({ id: 'slack:admin-1', kind: 'slack', display_name: 'Admin', created_at: now() });
+  grantRole({ user_id: 'slack:admin-1', role: 'owner', agent_group_id: null, granted_by: null, granted_at: now() });
+  createMessagingGroup({
+    id: 'mg-dm-1',
+    channel_type: DM_CHANNEL,
+    platform_id: DM_PLATFORM,
+    name: 'Admin DM',
+    is_group: 0,
+    unknown_sender_policy: 'strict',
+    created_at: now(),
+  });
+  upsertUserDm({
+    user_id: 'slack:admin-1',
+    channel_type: DM_CHANNEL,
+    messaging_group_id: 'mg-dm-1',
+    resolved_at: now(),
+  });
+
+  setDeliveryAdapter(fakeAdapter);
+});
+
+afterEach(() => {
+  closeDb();
+  if (fs.existsSync(TEST_DIR)) fs.rmSync(TEST_DIR, { recursive: true, force: true });
+});
+
+describe('reject with reason', () => {
+  it('holds the row and prompts the admin instead of finalizing', async () => {
+    seedApproval('appr-1');
+    await clickRejectWithReason('appr-1');
+
+    const row = getPendingApproval('appr-1');
+    expect(row?.status).toBe('awaiting_reason');
+    expect(row?.expires_at).toBeTruthy();
+
+    // Prompt went to the admin's resolved DM, not the (empty) click platformId.
+    expect(delivered).toHaveLength(1);
+    expect(delivered[0].channelType).toBe(DM_CHANNEL);
+    expect(delivered[0].platformId).toBe(DM_PLATFORM);
+    expect((JSON.parse(delivered[0].content) as { text: string }).text).toMatch(/reason/i);
+
+    // Agent is not notified yet — the hold is still open.
+    expect(vi.mocked(writeSessionMessage)).not.toHaveBeenCalled();
+  });
+
+  it('relays the captured reason as one combined message and clears the row', async () => {
+    const { captureReasonReply } = await import('./reason-capture.js');
+    seedApproval('appr-2', 'install_packages');
+    await clickRejectWithReason('appr-2');
+
+    const consumed = await captureReasonReply(dmReply('too risky for prod'));
+
+    expect(consumed).toBe(true);
+    expect(getPendingApproval('appr-2')).toBeUndefined();
+    expect(lastRelayedText()).toBe('Your install_packages request was rejected by admin: "too risky for prod"');
+  });
+
+  it('truncates an over-long reason to 280 chars with an ellipsis', async () => {
+    const { captureReasonReply } = await import('./reason-capture.js');
+    seedApproval('appr-3');
+    await clickRejectWithReason('appr-3');
+
+    await captureReasonReply(dmReply('x'.repeat(400)));
+
+    const reason = lastRelayedText()!.match(/: "(.*)"$/)![1];
+    expect(reason).toHaveLength(280);
+    expect(reason.endsWith('…')).toBe(true);
+  });
+
+  it('finalizes a plain reject when the captured reply carries no text', async () => {
+    const { captureReasonReply } = await import('./reason-capture.js');
+    seedApproval('appr-4');
+    await clickRejectWithReason('appr-4');
+
+    const consumed = await captureReasonReply(dmReply(undefined));
+
+    expect(consumed).toBe(true);
+    expect(getPendingApproval('appr-4')).toBeUndefined();
+    expect(lastRelayedText()).toBe('Your create_agent request was rejected by admin.');
+  });
+
+  it('does not swallow a later DM once the hold was already finalized', async () => {
+    const { captureReasonReply } = await import('./reason-capture.js');
+    seedApproval('appr-5');
+    await clickRejectWithReason('appr-5');
+    // Simulate the sweep (or any other path) finalizing first.
+    deletePendingApproval('appr-5');
+
+    const consumed = await captureReasonReply(dmReply('late reason'));
+
+    expect(consumed).toBe(false);
+  });
+
+  it('ignores DMs on channels with no armed reason capture', async () => {
+    const { captureReasonReply } = await import('./reason-capture.js');
+    const consumed = await captureReasonReply({
+      channelType: DM_CHANNEL,
+      platformId: 'D-someone-else',
+      threadId: null,
+      message: { id: 'm', kind: 'chat', content: JSON.stringify({ text: 'hi' }), timestamp: now() },
+    });
+    expect(consumed).toBe(false);
+  });
+});
+
+describe('reject-with-reason host sweep', () => {
+  it('finalizes a hold whose window elapsed as a plain reject', async () => {
+    const { sweepAwaitingReasonRejects } = await import('./reason-capture.js');
+    seedApproval('appr-ghost', 'add_mcp_server');
+    markApprovalAwaitingReason('appr-ghost', new Date(Date.now() - 1000).toISOString());
+
+    await sweepAwaitingReasonRejects();
+
+    expect(getPendingApproval('appr-ghost')).toBeUndefined();
+    expect(lastRelayedText()).toBe('Your add_mcp_server request was rejected by admin.');
+  });
+
+  it('leaves a still-open hold untouched', async () => {
+    const { sweepAwaitingReasonRejects } = await import('./reason-capture.js');
+    seedApproval('appr-open');
+    markApprovalAwaitingReason('appr-open', new Date(Date.now() + 60_000).toISOString());
+
+    await sweepAwaitingReasonRejects();
+
+    expect(getPendingApproval('appr-open')?.status).toBe('awaiting_reason');
+    expect(vi.mocked(writeSessionMessage)).not.toHaveBeenCalled();
+  });
+});
+
+describe('plain reject (regression)', () => {
+  it('finalizes immediately with no reason and no DM prompt', async () => {
+    const { handleApprovalsResponse } = await import('./response-handler.js');
+    seedApproval('appr-plain', 'install_packages');
+
+    await handleApprovalsResponse({
+      questionId: 'appr-plain',
+      value: 'reject',
+      userId: 'admin-1',
+      channelType: DM_CHANNEL,
+      platformId: '',
+      threadId: null,
+    });
+
+    expect(getPendingApproval('appr-plain')).toBeUndefined();
+    expect(delivered).toHaveLength(0);
+    expect(lastRelayedText()).toBe('Your install_packages request was rejected by admin.');
+  });
+});

src/modules/approvals/reason-capture.ts

@@ -0,0 +1,174 @@
+/**
+ * "Reject with reason…" capture flow.
+ *
+ * When an admin clicks the third approval button, the reject is held instead of
+ * finalized: the row is parked at status='awaiting_reason' and the admin is
+ * prompted in their DM for a one-line reason. Their next DM (≤ 280 chars) is
+ * captured by a router message-interceptor and relayed to the requesting agent
+ * as one combined message — `Your <action> request was rejected by admin:
+ * "<reason>"`. A plain Reject never arms this, so an unrelated DM is never
+ * swallowed.
+ *
+ * Restart-safety: arming lives in an in-memory map (lost on restart, like the
+ * agent-naming capture it mirrors), but the hold is a durable DB row. If the
+ * admin never replies — or the host restarts mid-capture — the host sweep
+ * (sweepAwaitingReasonRejects, run each tick) finalizes a plain reject once the
+ * row's window elapses, so the requesting agent is never stranded.
+ *
+ * Reuses, not reinvents: the agent-naming prompt-then-capture pattern
+ * (in-memory map + next-DM interceptor) and the shared finalizeReject path.
+ */
+import type { InboundEvent } from '../../channels/adapter.js';
+import { getDeliveryAdapter } from '../../delivery.js';
+import {
+  deletePendingApproval,
+  getExpiredAwaitingReasonApprovals,
+  getPendingApproval,
+  getSession,
+  markApprovalAwaitingReason,
+} from '../../db/sessions.js';
+import { log } from '../../log.js';
+import { registerMessageInterceptor } from '../../router.js';
+import type { PendingApproval, Session } from '../../types.js';
+import { ensureUserDm } from '../permissions/user-dm.js';
+import { finalizeReject } from './finalize.js';
+
+/** How long an awaiting-reason hold waits for the admin's reply before the sweep finalizes a plain reject. */
+const REASON_CAPTURE_WINDOW_MS = 5 * 60 * 1000;
+/** Cap on the relayed reason — one cheap guardrail against a wall of text landing in another team's agent context. */
+const MAX_REASON_LEN = 280;
+
+const PROMPT_TEXT =
+  "Reply with a one-line reason for the rejection — I'll relay it to the agent. " +
+  'No reply within ~5 min declines it without a reason.';
+
+interface ReasonArming {
+  approvalId: string;
+  /** Namespaced id of the admin who clicked, for resolution attribution. */
+  userId: string;
+}
+
+/**
+ * Approvers waiting to type a rejection reason, keyed by their DM channel
+ * (`<channelType>:<dmPlatformId>`). A DM's platform id is unique per user, so
+ * the inbound reply matches by channel alone — no sender re-parsing needed, and
+ * a group message can never collide with an armed DM. Cleared on receipt,
+ * staleness, or restart.
+ */
+const awaitingReason = new Map<string, ReasonArming>();
+
+function dmKey(channelType: string, platformId: string): string {
+  return `${channelType}:${platformId}`;
+}
+
+function clampReason(raw: string): string {
+  const trimmed = raw.trim();
+  if (trimmed.length <= MAX_REASON_LEN) return trimmed;
+  return trimmed.slice(0, MAX_REASON_LEN - 1) + '…';
+}
+
+function extractText(event: InboundEvent): string {
+  try {
+    const parsed = JSON.parse(event.message.content) as Record<string, unknown>;
+    return typeof parsed.text === 'string' ? parsed.text : '';
+  } catch {
+    return '';
+  }
+}
+
+/**
+ * Begin the reject-with-reason hold for an approval the admin chose not to
+ * finalize outright. Prompts the admin's DM, then parks the row and arms
+ * capture. If we can't reach the admin (no DM, no adapter, delivery throws) we
+ * finalize a plain reject immediately rather than strand the requesting agent.
+ */
+export async function armReasonCapture(approval: PendingApproval, session: Session, userId: string): Promise<void> {
+  const dm = userId ? await ensureUserDm(userId) : null;
+  const adapter = getDeliveryAdapter();
+  if (!dm || !adapter) {
+    log.warn('reject-with-reason: cannot reach approver, finalizing plain reject', {
+      approvalId: approval.approval_id,
+      userId,
+      hasDm: Boolean(dm),
+      hasAdapter: Boolean(adapter),
+    });
+    await finalizeReject(approval, session, userId);
+    return;
+  }
+
+  try {
+    await adapter.deliver(dm.channel_type, dm.platform_id, null, 'chat-sdk', JSON.stringify({ text: PROMPT_TEXT }));
+  } catch (err) {
+    log.error('reject-with-reason: reason prompt delivery failed, finalizing plain reject', {
+      approvalId: approval.approval_id,
+      err,
+    });
+    await finalizeReject(approval, session, userId);
+    return;
+  }
+
+  // Prompt is out — now hold the row and arm capture. Order matters: a reply
+  // can't arrive before the prompt is read, so there's no lost-message window.
+  const expiresAt = new Date(Date.now() + REASON_CAPTURE_WINDOW_MS).toISOString();
+  markApprovalAwaitingReason(approval.approval_id, expiresAt);
+  awaitingReason.set(dmKey(dm.channel_type, dm.platform_id), { approvalId: approval.approval_id, userId });
+  log.info('reject-with-reason: awaiting reason reply', { approvalId: approval.approval_id, userId });
+}
+
+/**
+ * Router message-interceptor: capture the next DM from an admin who armed a
+ * reason. Returns true (consume the message) when this DM is an armed reason
+ * channel and still holds a live row; false otherwise so normal routing runs.
+ *
+ * Exported for tests; registered as the interceptor below.
+ */
+export async function captureReasonReply(event: InboundEvent): Promise<boolean> {
+  const arming = awaitingReason.get(dmKey(event.channelType, event.platformId));
+  if (!arming) return false;
+
+  // This DM is an armed reason channel — disarm regardless of outcome.
+  awaitingReason.delete(dmKey(event.channelType, event.platformId));
+
+  const approval = getPendingApproval(arming.approvalId);
+  if (!approval || approval.status !== 'awaiting_reason') {
+    // Already finalized (e.g. ghosted by the sweep). The reply is no longer a
+    // reason — let it route normally instead of swallowing it.
+    return false;
+  }
+
+  const session = approval.session_id ? getSession(approval.session_id) : null;
+  if (!session) {
+    deletePendingApproval(approval.approval_id);
+    return true;
+  }
+
+  const reason = clampReason(extractText(event));
+  await finalizeReject(approval, session, arming.userId, reason || undefined);
+  log.info('reject-with-reason: reason captured and relayed', {
+    approvalId: approval.approval_id,
+    hasReason: reason.length > 0,
+  });
+  return true;
+}
+
+registerMessageInterceptor(captureReasonReply);
+
+/**
+ * Host-sweep finalizer: any reject-with-reason hold whose window elapsed (admin
+ * ghosted, or the host restarted mid-capture and lost the in-memory arming) is
+ * finalized as a plain reject. Restart-safe — the hold is a durable row, so the
+ * requesting agent always gets its decision. Called once per sweep tick.
+ */
+export async function sweepAwaitingReasonRejects(): Promise<void> {
+  const rows = getExpiredAwaitingReasonApprovals(new Date().toISOString());
+  for (const approval of rows) {
+    const session = approval.session_id ? getSession(approval.session_id) : null;
+    if (!session) {
+      deletePendingApproval(approval.approval_id);
+      continue;
+    }
+    // Plain reject, unknown resolver — the admin opted in but never typed.
+    await finalizeReject(approval, session, '');
+    log.info('reject-with-reason: window elapsed, finalized as plain reject', { approvalId: approval.approval_id });
+  }
+}

src/modules/approvals/response-handler.ts

@@ -5,7 +5,10 @@
  *   1. Module-initiated actions — the module called `requestApproval()` with
  *      some free-form `action` string and registered a handler via
  *      `registerApprovalHandler(action, handler)`. On approve, we look up the
- *      handler and call it; on reject, we notify the agent and move on.
+ *      handler and call it; on plain reject we relay a decline to the agent; on
+ *      "Reject with reason…" we hold the row and capture the admin's next DM as
+ *      a one-line reason (see reason-capture.ts). Reject finalization is shared
+ *      via finalizeReject.
  *   2. OneCLI credential approvals (`action = 'onecli_credential'`). Resolved
  *      via an in-memory Promise — see onecli-approvals.ts.
  *
@@ -19,8 +22,10 @@ import { log } from '../../log.js';
 import { writeSessionMessage } from '../../session-manager.js';
 import type { PendingApproval } from '../../types.js';
 import { hasAdminPrivilege, isGlobalAdmin, isOwner } from '../permissions/db/user-roles.js';
+import { finalizeReject } from './finalize.js';
 import { ONECLI_ACTION, resolveOneCLIApproval } from './onecli-approvals.js';
-import { getApprovalHandler, notifyApprovalResolved } from './primitive.js';
+import { getApprovalHandler, notifyApprovalResolved, REJECT_WITH_REASON_VALUE } from './primitive.js';
+import { armReasonCapture } from './reason-capture.js';
 
 export async function handleApprovalsResponse(payload: ResponsePayload): Promise<boolean> {
   const approval = getPendingApproval(payload.questionId);
@@ -65,6 +70,21 @@ async function handleRegisteredApproval(
     return;
   }
 
+  // "Reject with reason…" — hold the row and capture the admin's next DM
+  // instead of finalizing now. The agent is notified exactly once: after the
+  // reason arrives, or after the sweep's timeout if the admin ghosts.
+  if (selectedOption === REJECT_WITH_REASON_VALUE) {
+    await armReasonCapture(approval, session, userId);
+    return;
+  }
+
+  // Plain Reject (or any other non-approve value) — instant fast path.
+  if (selectedOption !== 'approve') {
+    await finalizeReject(approval, session, userId);
+    return;
+  }
+
+  // Approved — dispatch to the module that registered for this action.
   const notify = (text: string): void => {
     writeSessionMessage(session.agent_group_id, session.id, {
       id: `appr-note-${Date.now()}-${Math.random().toString(36).slice(2, 8)}`,
@@ -77,16 +97,6 @@ async function handleRegisteredApproval(
     });
   };
 
-  if (selectedOption !== 'approve') {
-    notify(`Your ${approval.action} request was rejected by admin.`);
-    log.info('Approval rejected', { approvalId: approval.approval_id, action: approval.action, userId });
-    deletePendingApproval(approval.approval_id);
-    await notifyApprovalResolved({ approval, session, outcome: 'reject', userId });
-    await wakeContainer(session);
-    return;
-  }
-
-  // Approved — dispatch to the module that registered for this action.
   const handler = getApprovalHandler(approval.action);
   if (!handler) {
     log.warn('No approval handler registered — row dropped', {

src/modules/permissions/index.ts

@@ -22,7 +22,7 @@ import {
   routeInbound,
   setAccessGate,
   setChannelRequestGate,
-  setMessageInterceptor,
+  registerMessageInterceptor,
   setSenderResolver,
   setSenderScopeGate,
   type AccessGateResult,
@@ -521,7 +521,7 @@ registerResponseHandler(handleChannelApprovalResponse);
 // Captures the next DM from an approver who clicked "Create new agent",
 // creates the agent immediately, wires the channel, and replays.
 
-setMessageInterceptor(async (event: InboundEvent): Promise<boolean> => {
+registerMessageInterceptor(async (event: InboundEvent): Promise<boolean> => {
   const userId = extractAndUpsertUser(event);
   if (!userId) return false;
 

src/router.ts

@@ -110,16 +110,20 @@ export function setSenderScopeGate(fn: SenderScopeGateFn): void {
 
 /**
  * Message-interceptor hook. Runs at the very top of routeInbound, before
- * messaging-group resolution. When the interceptor returns true the message
- * is consumed and routing stops. Used by the permissions module to capture
- * free-text replies during multi-step approval flows (e.g. agent naming).
+ * messaging-group resolution. When an interceptor returns true the message is
+ * consumed and routing stops. Multiple interceptors may register; they run in
+ * registration order and the first to claim the message (return true) wins.
+ *
+ * Used by modules to capture free-text DM replies during multi-step approval
+ * flows — the permissions module (agent naming during channel registration)
+ * and the approvals module (reject-with-reason capture).
  */
 export type MessageInterceptorFn = (event: InboundEvent) => Promise<boolean>;
 
-let messageInterceptor: MessageInterceptorFn | null = null;
+const messageInterceptors: MessageInterceptorFn[] = [];
 
-export function setMessageInterceptor(fn: MessageInterceptorFn): void {
-  messageInterceptor = fn;
+export function registerMessageInterceptor(fn: MessageInterceptorFn): void {
+  messageInterceptors.push(fn);
 }
 
 /**
@@ -156,9 +160,13 @@ function safeParseContent(raw: string): { text?: string; sender?: string; sender
  * Creates messaging group + session if they don't exist yet.
  */
 export async function routeInbound(event: InboundEvent): Promise<void> {
-  // Pre-route interceptor — lets modules consume messages before any routing
-  // (e.g. free-text replies during multi-step approval flows).
-  if (messageInterceptor && (await messageInterceptor(event))) return;
+  // Pre-route interceptors — let modules consume messages before any routing
+  // (e.g. free-text DM replies during multi-step approval flows). They run in
+  // registration order; the first to claim the message stops routing. The
+  // sequential await is intentional — first-to-claim is order-dependent.
+  for (const intercept of messageInterceptors) {
+    if (await intercept(event)) return;
+  }
 
   // 0. Apply the adapter's thread policy. Non-threaded adapters (Telegram,
   //    WhatsApp, iMessage, email) collapse threads to the channel. Resolved

src/types.ts

@@ -200,8 +200,13 @@ export interface PendingApproval {
   channel_type: string | null;
   platform_id: string | null;
   platform_message_id: string | null;
+  /**
+   * For OneCLI credential rows, the gateway's request TTL. For a module
+   * approval held by "Reject with reason…", the deadline after which the
+   * host sweep finalizes a plain reject (set by markApprovalAwaitingReason).
+   */
   expires_at: string | null;
-  status: 'pending' | 'approved' | 'rejected' | 'expired';
+  status: 'pending' | 'approved' | 'rejected' | 'expired' | 'awaiting_reason';
   title: string;
   options_json: string;
 }