diff --git a/backend/__tests__/service/uninstallRevokesRuntimeCredential.test.js b/backend/__tests__/service/uninstallRevokesRuntimeCredential.test.js
new file mode 100644
index 000000000..16dc485ea
--- /dev/null
+++ b/backend/__tests__/service/uninstallRevokesRuntimeCredential.test.js
@@ -0,0 +1,147 @@
+// Every way an agent's last installation goes away retires its runtime
+// token (TASK-625), the way the uninstall routes do (#2221): deleting the pod
+// and pruning a stale install now do it too, and a reinstall of the same
+// identity starts from a fresh token.
+//
+// A real mongod, because the claim is about which stored records survive; the
+// probe is the real runtime auth middleware, so "dead" means what an agent
+// would see: its next call is a 401.
+const express = require('express');
+const rateLimit = require('express-rate-limit');
+const request = require('supertest');
+const mongoose = require('mongoose');
+const { setupMongoDb, closeMongoDb, clearMongoDb } = require('../utils/testUtils');
+
+process.env.PG_HOST = '';
+process.env.NODE_ENV = 'test';
+
+jest.mock('../../services/starterTaskService', () => ({ completeConnectAgentStarterTask: jest.fn() }));
+
+const Pod = require('../../models/Pod');
+const Message = require('../../models/Message');
+const User = require('../../models/User');
+const AgentCredential = require('../../models/AgentCredential');
+const { AgentInstallation } = require('../../models/AgentRegistry');
+const AgentIdentityService = require('../../services/agentIdentityService');
+const tokens = require('../../routes/registry/tokens');
+
+const { issueRuntimeTokenForAgent } = tokens;
+const { deletePodCascade } = require('../../services/podDeletionService');
+const { pruneStaleInstallations } = require('../../services/agentInstallationCleanupService');
+const agentRuntimeAuth = require('../../middleware/agentRuntimeAuth');
+
+const app = express();
+const probeLimit = rateLimit({ windowMs: 60 * 1000, max: 10000 });
+app.get('/probe', probeLimit, agentRuntimeAuth, (req, res) => res.json({ agent: req.agentUser?.username || null }));
+const probe = (token) => request(app).get('/probe').set('Authorization', `Bearer ${token}`);
+
+const AGENT = 'maya-claude';
+const ownerId = new mongoose.Types.ObjectId();
+
+const makePod = (name) => Pod.create({ name, type: 'chat', createdBy: ownerId, members: [ownerId] });
+const install = (pod, extra = {}) => AgentInstallation.create({
+  agentName: AGENT,
+  instanceId: 'default',
+  podId: pod._id,
+  installedBy: ownerId,
+  status: 'active',
+  displayName: 'Maya Claude',
+  version: '1.0.0',
+  ...extra,
+});
+
+const issue = async (installation) => {
+  const agentUser = await AgentIdentityService.getOrCreateAgentUser(AGENT, { instanceId: 'default' });
+  const issued = await issueRuntimeTokenForAgent(agentUser, 'CLI key', installation, { ownerUserId: ownerId });
+  return issued.token;
+};
+
+const credentialStatus = async () => {
+  const rows = await AgentCredential.find({ kind: 'runtime' }).select('status').lean();
+  return rows.map((row) => row.status);
+};
+
+describe('the last installation going away revokes the runtime token', () => {
+  beforeAll(async () => { await setupMongoDb(); });
+  afterAll(async () => { await closeMongoDb(); });
+  beforeEach(async () => {
+    await clearMongoDb();
+    jest.spyOn(console, 'warn').mockImplementation(() => {});
+  });
+  afterEach(() => jest.restoreAllMocks());
+
+  test('deleting the only pod revokes it, and a reinstall does not revive it', async () => {
+    const pod = await makePod('Only pod');
+    const token = await issue(await install(pod));
+    expect((await probe(token)).status).toBe(200);
+
+    await deletePodCascade(String(pod._id));
+
+    expect(await credentialStatus()).toEqual(['revoked']);
+    expect(await User.countDocuments({ 'agentRuntimeTokens.0': { $exists: true } })).toBe(0);
+    await install(await makePod('New pod'));
+    expect((await probe(token)).status).toBe(401);
+  });
+
+  test('deleting one of two pods leaves the token working', async () => {
+    const pod = await makePod('Doomed');
+    const keep = await makePod('Kept');
+    const token = await issue(await install(pod));
+    await install(keep);
+
+    await deletePodCascade(String(pod._id));
+
+    expect(await credentialStatus()).toEqual(['active']);
+    expect((await probe(token)).status).toBe(200);
+  });
+
+  test('pruning the last stale install revokes it, and a reinstall does not revive it', async () => {
+    const pod = await makePod('Stale pod');
+    const installation = await install(pod);
+    const token = await issue(installation);
+    await AgentInstallation.updateOne(
+      { _id: installation._id },
+      { $set: { status: 'stale', staleSince: new Date(Date.now() - 30 * 24 * 60 * 60 * 1000) } },
+    );
+
+    const result = await pruneStaleInstallations(14);
+
+    expect(result).toEqual({ deleted: 1, failures: 0 });
+    expect(await credentialStatus()).toEqual(['revoked']);
+    await install(pod);
+    expect((await probe(token)).status).toBe(401);
+  });
+  test('a prune whose revoke fails keeps the row, and the next run finishes the job', async () => {
+    const pod = await makePod('Retry pod');
+    const installation = await install(pod);
+    await issue(installation);
+    await AgentInstallation.updateOne(
+      { _id: installation._id },
+      { $set: { status: 'stale', staleSince: new Date(Date.now() - 30 * 24 * 60 * 60 * 1000) } },
+    );
+    jest.spyOn(console, 'error').mockImplementation(() => {});
+    jest.spyOn(tokens, 'revokeRuntimeTokensAfterLastUninstall').mockRejectedValueOnce(new Error('db blip'));
+
+    expect(await pruneStaleInstallations(14)).toEqual({ deleted: 0, failures: 1 });
+    expect(await AgentInstallation.countDocuments({ _id: installation._id })).toBe(1);
+    expect(await credentialStatus()).toEqual(['active']);
+
+    expect(await pruneStaleInstallations(14)).toEqual({ deleted: 1, failures: 0 });
+    expect(await credentialStatus()).toEqual(['revoked']);
+  });
+  test('a pod deletion whose revoke fails deletes nothing, and the retry revokes', async () => {
+    const pod = await makePod('Retry delete');
+    await issue(await install(pod));
+    await Message.create({ podId: pod._id, userId: ownerId, content: 'keep me' });
+    jest.spyOn(tokens, 'revokeRuntimeTokensAfterLastUninstall').mockRejectedValueOnce(new Error('db blip'));
+
+    await expect(deletePodCascade(String(pod._id))).rejects.toThrow('db blip');
+    expect(await Pod.countDocuments({ _id: pod._id })).toBe(1);
+    expect(await Message.countDocuments({ podId: pod._id })).toBe(1);
+    expect(await AgentInstallation.countDocuments({ podId: pod._id })).toBe(1);
+
+    await deletePodCascade(String(pod._id));
+    expect(await credentialStatus()).toEqual(['revoked']);
+    expect(await Pod.countDocuments({ _id: pod._id })).toBe(0);
+  });
+});
diff --git a/backend/__tests__/unit/controllers/podController.test.js b/backend/__tests__/unit/controllers/podController.test.js
index 2bd4a235c..2c522fc59 100644
--- a/backend/__tests__/unit/controllers/podController.test.js
+++ b/backend/__tests__/unit/controllers/podController.test.js
@@ -30,6 +30,9 @@ jest.mock('../../../models/AgentRegistry', () => ({
     isInstalled: jest.fn(),
     install: jest.fn(),
     deleteMany: jest.fn(),
+    // deletePodCascade reads the pod's agents before deleting them.
+    find: jest.fn(() => ({ select: () => ({ lean: async () => [] }) })),
+    updateMany: jest.fn(),
   },
 }));
 jest.mock('../../../models/AgentProfile', () => ({
diff --git a/backend/__tests__/unit/routes/hosted.test.js b/backend/__tests__/unit/routes/hosted.test.js
index f3051f544..a1bb25897 100644
--- a/backend/__tests__/unit/routes/hosted.test.js
+++ b/backend/__tests__/unit/routes/hosted.test.js
@@ -405,6 +405,10 @@ describe('/api/hosted', () => {
     expect(res.status).toBe(200);
     expect(res.body).toMatchObject({ deprovisioned: true });
     expect(installation.config.get('hosted').provisionedAt).toBeNull();
+    // The stopped worker held the only copy; nothing else may keep using it.
+    expect(mockRevokeRuntimeTokens).toHaveBeenCalledWith(expect.objectContaining({
+      agentName: 'scout', instanceId: 'default', installation,
+    }));
   });
 
   // TASK-265: a migration that marks the row native while the
diff --git a/backend/routes/hosted.ts b/backend/routes/hosted.ts
index f3e3957e9..a93178871 100644
--- a/backend/routes/hosted.ts
+++ b/backend/routes/hosted.ts
@@ -354,8 +354,7 @@ router.post('/provision', hostedRateLimit, auth, async (req: any, res: any) => {
  * POST /api/hosted/deprovision { agentName, instanceId? }
  * Stops the runtime. The installation and identity stay — ADR-001 §3 identity
  * continuity; re-provisioning finds the same memory. The token does NOT
- * survive: provision rotates on every call, so a
- * re-provision mints fresh and orphans anything still holding the old one.
+ * survive: it is revoked here, and provision mints a fresh one.
  */
 router.post('/deprovision', hostedRateLimit, auth, async (req: any, res: any) => {
   try {
@@ -375,6 +374,17 @@ router.post('/deprovision', hostedRateLimit, auth, async (req: any, res: any) =>
     }
     if (!requireConfigured(res, hostedEngineOf(installation))) return undefined;
     await hostedRuntime.deprovisionAgent(agentName, instanceId);
+    // The stopped runtime was the token's only holder. Revoke it now rather
+    // than at the next provision, which may never come.
+    // Without a bot user the installation copies are still revoked.
+    const agentUser = await User.findOne({
+      username: AgentIdentityService.buildAgentUsername(agentName, instanceId),
+      isBot: true,
+    });
+    await revokeRuntimeTokensForAgent({ agentUser, agentName, instanceId, installation });
+    // A socket authenticated with the old token stays open until told to go.
+    // eslint-disable-next-line global-require, @typescript-eslint/no-require-imports
+    require('../services/agentWebSocketService').disconnectIdentity(agentName, instanceId);
     // A row migrated meanwhile keeps the migration's record; the worker is
     // stopped either way, which is what both wanted.
     await writeDurableObjectRecord(installation, { provisionedAt: null, deprovisionedAt: new Date() });
diff --git a/backend/services/agentInstallationCleanupService.ts b/backend/services/agentInstallationCleanupService.ts
index cee9dbee8..455507b03 100644
--- a/backend/services/agentInstallationCleanupService.ts
+++ b/backend/services/agentInstallationCleanupService.ts
@@ -312,8 +312,15 @@ export async function pruneStaleInstallations(
         await Pod.updateOne({ _id: inst.podId }, { $pull: { members: agentUser._id } });
       }
 
-      await AgentInstallation.deleteOne({ _id: inst._id });
-      deleted += 1;
+      // A pruned install is an uninstall: once none is active, the agent's
+      // runtime token stops authenticating too. A stale row is not active, so
+      // revoke first; if it throws, the row survives for the next run.
+      // eslint-disable-next-line global-require, @typescript-eslint/no-require-imports
+      const { revokeRuntimeTokensAfterLastUninstall } = require('../routes/registry/tokens');
+      await revokeRuntimeTokensAfterLastUninstall(inst.agentName, inst.instanceId || 'default');
+      // Only if still stale: a reinstall may have reactivated the row meanwhile.
+      const removed = await AgentInstallation.deleteOne({ _id: inst._id, status: 'stale' });
+      if (removed?.deletedCount) deleted += 1;
     } catch (err) {
       console.error(
         '[installation-cleanup] failed to prune install %s (%s/%s): %s',
diff --git a/backend/services/podDeletionService.ts b/backend/services/podDeletionService.ts
index af68e53a3..9d08dd307 100644
--- a/backend/services/podDeletionService.ts
+++ b/backend/services/podDeletionService.ts
@@ -22,6 +22,27 @@ if (process.env.PG_HOST) {
 }
 
 export const deletePodCascade = async (podId: string): Promise<void> => {
+  // An agent whose last install was in this pod loses its runtime token, as
+  // on uninstall. Uninstall the rows and revoke before deleting anything:
+  // if a revoke throws, the rows are still here and a retried delete finds
+  // them again. The helper counts active installs, so an agent installed in
+  // another pod keeps its token.
+  const installedAgents = await AgentInstallation.find({ podId })
+    .select('agentName instanceId').lean();
+  await AgentInstallation.updateMany({ podId }, { $set: { status: 'uninstalled' } });
+  const identities = new Map<string, { agentName: string; instanceId: string }>();
+  for (const row of installedAgents || []) {
+    const instanceId = row.instanceId || 'default';
+    identities.set(`${row.agentName}:${instanceId}`, { agentName: row.agentName, instanceId });
+  }
+  // eslint-disable-next-line global-require, @typescript-eslint/no-require-imports
+  const { revokeRuntimeTokensAfterLastUninstall } = require('../routes/registry/tokens');
+  for (const { agentName, instanceId } of identities.values()) {
+    await revokeRuntimeTokensAfterLastUninstall(agentName, instanceId);
+  }
+
+  // Nothing irreversible runs before the revoke above, so a failure there
+  // leaves the pod and its content for the retry.
   // A hierarchy link is not ownership. Keep children and their contents.
   await Pod.updateMany({ parentPod: podId }, { $unset: { parentPod: 1 } });
   await Message.deleteMany({ podId });