fix(mosaic): bound promotion transport delivery

packages/mosaic/src/commands/promote.spec.ts

@@ -1,9 +1,12 @@
 import { Command } from 'commander';
 import { describe, expect, it, vi } from 'vitest';
+import type { FleetRoster } from './fleet.js';
+import { TmuxPromotionTransport } from '../fleet/promotion-transport.js';
 import {
   promoteSeat,
   registerPromoteCommand,
   type PromotionBreadcrumbStore,
+  type PromotionResult,
   type PromotionTransport,
 } from './promote.js';
 
@@ -94,6 +97,46 @@ describe('mosaic promote', () => {
     expect(result.status).toBe('VERIFIED');
   });
 
+  it('returns UNVERIFIED within the command bound when a tmux runner wedges', async () => {
+    vi.useFakeTimers();
+    const roster: FleetRoster = {
+      agents: [{ className: 'worker', name: 'claude-seat', runtime: 'claude' }],
+      defaults: { workingDirectory: '~/src' },
+      runtimes: {},
+      tmux: { holderSession: '_holder', socketName: 'mosaic-fleet' },
+      transport: 'tmux',
+      version: 1,
+    };
+    const promotionTransport = new TmuxPromotionTransport({
+      mosaicHome: '/mosaic',
+      rosterLoader: async () => roster,
+      runner: async () => new Promise(() => {}),
+    });
+    const store: PromotionBreadcrumbStore = {
+      readAttemptId: vi.fn(async () => null),
+      readResult: vi.fn(async () => null),
+    };
+
+    try {
+      let observedResult: PromotionResult | undefined;
+      void promoteSeat('claude-seat', {
+        store,
+        transport: promotionTransport,
+      }).then((result) => {
+        observedResult = result;
+      });
+      await vi.advanceTimersByTimeAsync(5_000);
+
+      expect(observedResult).toMatchObject({
+        reason: 'RESOLVE_FAILED: Promotion transport command timed out after 5000ms.',
+        seat: 'claude-seat',
+        status: 'UNVERIFIED',
+      });
+    } finally {
+      vi.useRealTimers();
+    }
+  });
+
   it('prints VERIFIED with the resolved seat, session, bundle, and wall-clock expiry', async () => {
     const promotionTransport = transport();
     const store: PromotionBreadcrumbStore = {
@@ -123,6 +166,34 @@ describe('mosaic promote', () => {
     }
   });
 
+  it('prints UNVERIFIED and exits 1 when delivery fails', async () => {
+    const promotionTransport: PromotionTransport = {
+      resolve: vi.fn(async () => target),
+      sendPromotion: vi.fn(async () => {
+        throw new Error('tmux unavailable');
+      }),
+    };
+    const store: PromotionBreadcrumbStore = {
+      readAttemptId: vi.fn(async () => null),
+      readResult: vi.fn(async () => null),
+    };
+    const output = vi.spyOn(console, 'log').mockImplementation(() => {});
+    const program = new Command().exitOverride();
+    registerPromoteCommand(program, { store, transport: promotionTransport });
+
+    try {
+      process.exitCode = undefined;
+      await program.parseAsync(['node', 'mosaic', 'promote', 'claude-seat']);
+      expect(output).toHaveBeenCalledWith(
+        `UNVERIFIED seat=claude-seat session=${target.sessionId} bundle=local expiry=none reason=DELIVERY_FAILED: tmux unavailable`,
+      );
+      expect(process.exitCode).toBe(1);
+    } finally {
+      output.mockRestore();
+      process.exitCode = undefined;
+    }
+  });
+
   it('rejects a stale result even when its nonce matches', async () => {
     const promotionTransport = transport();
     let now = 1_000;

packages/mosaic/src/commands/promote.ts

@@ -15,6 +15,7 @@ import { resolveFleetPaths, type CommandRunner } from './fleet.js';
 const ATTEMPT_ID_PATTERN = /^[a-f0-9]{64}$/;
 const DEFAULT_POLL_INTERVAL_MS = 250;
 const DEFAULT_TIMEOUT_MS = 30_000;
+const SUBPROCESS_TIMEOUT_MS = 4_500;
 const PENDING_DIRECTORY = 'mosaic-lease';
 const RESULT_FILE = 'last-result.json';
 
@@ -92,7 +93,12 @@ export async function promoteSeat(
   const sleep = options.sleep ?? defaultSleep;
   const timeoutMs = normalizeTimeout(options.timeoutMs);
   const pollIntervalMs = normalizePollInterval(options.pollIntervalMs);
-  const target = await options.transport.resolve(seat);
+  let target: PromotionTarget;
+  try {
+    target = await options.transport.resolve(seat);
+  } catch (error: unknown) {
+    return unverifiedUnresolvedSeat(seat, `RESOLVE_FAILED: ${errorMessage(error)}`);
+  }
   const previousAttemptId = await options.store.readAttemptId(target.sessionId);
   const preSendTimestamp = clock();
   try {
@@ -109,6 +115,9 @@ export async function promoteSeat(
       attemptId = currentAttemptId;
     }
     if (attemptId !== null || previousAttemptId === null) {
+      // Completion can consume a first attempt's nonce before this poll observes it.
+      // In that branch, correlation degrades to session_id + fresh timestamp, which
+      // is acceptable for this 0600, same-UID local trust boundary.
       const breadcrumb = await options.store.readResult();
       if (
         breadcrumb !== null &&
@@ -233,6 +242,17 @@ function parseOptionTimeout(value: string | undefined): number | undefined {
   return Number.isFinite(parsed) ? parsed : undefined;
 }
 
+function unverifiedUnresolvedSeat(seat: string, reason: string): PromotionResult {
+  return {
+    bundle: 'unresolved',
+    expiresAtWallclock: null,
+    reason,
+    seat,
+    sessionId: 'unresolved',
+    status: 'UNVERIFIED',
+  };
+}
+
 function unverified(target: PromotionTarget, reason: string): PromotionResult {
   return {
     bundle: target.bundle,
@@ -268,6 +288,21 @@ function runCommand(
     const child = spawn(command, args, { stdio: ['ignore', 'pipe', 'pipe'] });
     let stdout = '';
     let stderr = '';
+    let settled = false;
+    const finish = (result: { exitCode: number; stderr: string; stdout: string }): void => {
+      if (settled) return;
+      settled = true;
+      clearTimeout(timeout);
+      resolve(result);
+    };
+    const timeout = setTimeout(() => {
+      child.kill('SIGKILL');
+      finish({
+        exitCode: 124,
+        stderr: `Promotion transport subprocess timed out after ${SUBPROCESS_TIMEOUT_MS}ms.`,
+        stdout,
+      });
+    }, SUBPROCESS_TIMEOUT_MS);
     child.stdout.on('data', (chunk: Buffer) => {
       stdout += chunk.toString('utf8');
     });
@@ -275,10 +310,10 @@ function runCommand(
       stderr += chunk.toString('utf8');
     });
     child.on('error', (error: Error) => {
-      resolve({ exitCode: 127, stderr: error.message, stdout });
+      finish({ exitCode: 127, stderr: error.message, stdout });
     });
     child.on('close', (code: number | null) => {
-      resolve({ exitCode: code ?? 1, stderr, stdout });
+      finish({ exitCode: code ?? 1, stderr, stdout });
     });
   });
 }

packages/mosaic/src/fleet/promotion-transport.spec.ts

@@ -17,10 +17,11 @@ function result(stdout = '', exitCode = 0, stderr = ''): CommandResult {
 }
 
 describe('TmuxPromotionTransport', () => {
-  it('resolves the exact roster seat and sends through the maintained tmux sender', async () => {
+  it('resolves the exact roster seat and sends the registered command literally', async () => {
     const runner = vi
       .fn<CommandRunner>()
       .mockResolvedValueOnce(result('1234 claude 0 0 0 0\n'))
+      .mockResolvedValueOnce(result())
       .mockResolvedValueOnce(result());
     const environmentReader = vi.fn(async () => `MOSAIC_LEASE_SESSION_ID=${sessionId}\0`);
     const transport = new TmuxPromotionTransport({
@@ -39,15 +40,22 @@ describe('TmuxPromotionTransport', () => {
       sessionId,
     });
     expect(environmentReader).toHaveBeenCalledWith(1234);
-    expect(runner).toHaveBeenNthCalledWith(2, '/mosaic/tools/tmux/agent-send.sh', [
+    expect(runner).toHaveBeenNthCalledWith(2, 'tmux', [
       '-L',
       'mosaic-fleet',
-      '-S',
+      'send-keys',
-      expect.stringMatching(/:operator$/),
+      '-t',
-      '-s',
+      '=claude-seat:0.0',
-      'claude-seat',
+      '-l',
-      '-m',
       '/mosaic-promote',
     ]);
+    expect(runner).toHaveBeenNthCalledWith(3, 'tmux', [
+      '-L',
+      'mosaic-fleet',
+      'send-keys',
+      '-t',
+      '=claude-seat:0.0',
+      'Enter',
+    ]);
   });
 });

packages/mosaic/src/fleet/promotion-transport.ts

@@ -1,8 +1,6 @@
 import { readFile } from 'node:fs/promises';
 import {
-  buildAgentSendCommand,
   buildTmuxListPanesCommand,
-  getDefaultOperatorSourceLabel,
   getRosterAgent,
   parseTmuxListPanes,
   resolveFleetPaths,
@@ -10,11 +8,13 @@ import {
   type CommandRunner,
   type FleetRoster,
   RUNTIME_ACCEPTABLE_COMMANDS,
+  socketArgs,
 } from '../commands/fleet.js';
 import { loadFleetRoster } from './fleet-roster-v1.js';
 
 const PROMOTION_COMMAND = '/mosaic-promote';
 const SESSION_ID_PATTERN = /^[a-f0-9]{64}$/;
+const TRANSPORT_COMMAND_TIMEOUT_MS = 5_000;
 
 export interface PromotionTarget {
   bundle: string;
@@ -81,16 +81,34 @@ export class TmuxPromotionTransport implements PromotionTransport {
   }
 
   async sendPromotion(target: PromotionTarget): Promise<void> {
-    const command = buildAgentSendCommand(
+    const targetPane = `=${target.seat}:0.0`;
-      resolveFleetPaths(this.options.mosaicHome),
+    const socketName = target.bundle === 'default' ? '' : target.bundle;
-      target.seat,
+    // Registered Claude commands must arrive as their exact literal text; the
+    // fleet agent sender prepends an identity envelope, so it cannot carry this
+    // command without preventing the UserPromptSubmit matcher from recognizing it.
+    await this.runPromotionCommand([
+      'tmux',
+      ...socketArgs(socketName),
+      'send-keys',
+      '-t',
+      targetPane,
+      '-l',
       PROMOTION_COMMAND,
-      target.bundle === 'default' ? '' : target.bundle,
+    ]);
-      getDefaultOperatorSourceLabel(),
+    await this.runPromotionCommand([
-    );
+      'tmux',
+      ...socketArgs(socketName),
+      'send-keys',
+      '-t',
+      targetPane,
+      'Enter',
+    ]);
+  }
+
+  private async runPromotionCommand(command: string[]): Promise<void> {
     const result = await this.run(command);
     if (result.exitCode !== 0) {
-      throw new Error(`Promotion command delivery failed: ${target.seat}.`);
+      throw new Error('Promotion command delivery failed.');
     }
   }
 
@@ -99,10 +117,28 @@ export class TmuxPromotionTransport implements PromotionTransport {
     if (executable === undefined) {
       throw new Error('Promotion transport command is empty.');
     }
-    return this.options.runner(executable, args);
+    return await withTimeout(this.options.runner(executable, args), TRANSPORT_COMMAND_TIMEOUT_MS);
   }
 }
 
+function withTimeout<T>(operation: Promise<T>, timeoutMs: number): Promise<T> {
+  return new Promise((resolve, reject) => {
+    const timeout = setTimeout(() => {
+      reject(new Error(`Promotion transport command timed out after ${timeoutMs}ms.`));
+    }, timeoutMs);
+    void operation.then(
+      (value) => {
+        clearTimeout(timeout);
+        resolve(value);
+      },
+      (error: unknown) => {
+        clearTimeout(timeout);
+        reject(error);
+      },
+    );
+  });
+}
+
 async function readPaneEnvironment(pid: number): Promise<string> {
   return readFile(`/proc/${pid}/environ`, 'utf8');
 }

packages/mosaic/src/lease-broker/promotion_trigger_unittest.py

@@ -410,6 +410,33 @@ class PromotionCompleteTest(PromotionHookFixture):
         self.assertTrue(self.pending_file.exists())
         self.assertIn("ConnectionRefusedError", stderr)
 
+    def test_result_write_failure_exits_zero(self) -> None:
+        self.write_pending()
+        runner = mock.Mock(
+            return_value=self.completed(
+                {"stage": "promote_lease", "ok": True, "state": "VERIFIED"}
+            )
+        )
+
+        with mock.patch.object(self.complete, "write_result", side_effect=OSError("disk full")):
+            result, stderr = self.run_complete(runner)
+
+        self.assertEqual(result, 0)
+        self.assertIn("OSError", stderr)
+
+    def test_missing_lease_session_id_exits_zero(self) -> None:
+        self.write_pending()
+        environment = dict(self.environment)
+        del environment["MOSAIC_LEASE_SESSION_ID"]
+        runner = mock.Mock()
+        stderr = io.StringIO()
+
+        result = self.complete.main(environ=environment, stderr=stderr, run=runner)
+
+        self.assertEqual(result, 0)
+        runner.assert_not_called()
+        self.assertIn("KeyError", stderr.getvalue())
+
     def test_insecure_runtime_directory_mode_preserves_pending(self) -> None:
         self.write_pending(CHALLENGE)
         self.runtime_dir.chmod(0o755)