diff --git a/apps/control-plane/src/app.ts b/apps/control-plane/src/app.ts
index b9e1bf3..a7f859e 100644
--- a/apps/control-plane/src/app.ts
+++ b/apps/control-plane/src/app.ts
@@ -11,6 +11,7 @@ import {
   matchDaemon,
   createGitHubAuth,
   postComment,
+  updateComment,
   buildManifest,
   exchangeManifestCode,
   saveCredentials,
@@ -1411,7 +1412,35 @@ export async function createControlPlaneApp(deps: ControlPlaneDeps) {
       // Dispatch to worker
       dispatchSession(discovery, legacyWorkerClient, sessionStore, sessionId, sessionRequest);
 
+      // Post initial PR comment for pull_request events
+      let prCommentId: number | undefined;
+      if (event.type === 'pull_request') {
+        const daemonRole = daemon.role;
+        const initialBody = [
+          `### 🐾 paws — ${daemonRole}`,
+          '',
+          '**Status:** ⏳ Running...',
+          '',
+          '---',
+          `*[View session](/sessions/${sessionId})*`,
+        ].join('\n');
+
+        prCommentId = await postComment(
+          { auth: githubAuth },
+          event.installationId,
+          event.issueUrl,
+          initialBody,
+        ).catch((err) => {
+          createLogger('github').error('Failed to post initial PR comment', {
+            sessionId,
+            error: String(err),
+          });
+          return undefined;
+        });
+      }
+
       // Listen for completion to post results back
+      const startTime = Date.now();
       const resultListener = (
         updatedId: string,
         session: import('./store/sessions.js').StoredSession,
@@ -1422,6 +1451,57 @@ export async function createControlPlaneApp(deps: ControlPlaneDeps) {
 
         sessionEvents.off('update', resultListener);
 
+        // For PR events, update the existing comment
+        if (event.type === 'pull_request' && prCommentId) {
+          const durationSec = Math.round((Date.now() - startTime) / 1000);
+          const repoParts = event.repo.split('/');
+          const owner = repoParts[0] ?? '';
+          const repo = repoParts[1] ?? '';
+          const daemonRole = daemon.role;
+          let body: string;
+
+          if (session.status === 'completed') {
+            const output =
+              (session.output as string) ?? session.stdout ?? 'Agent completed with no output.';
+            body = [
+              `### 🐾 paws — ${daemonRole}`,
+              '',
+              `**Status:** ✅ Completed in ${durationSec}s`,
+              '',
+              output,
+              '',
+              '---',
+              `*[View session](/sessions/${sessionId})*`,
+            ].join('\n');
+          } else {
+            const reason = session.stderr ?? session.status;
+            body = [
+              `### 🐾 paws — ${daemonRole}`,
+              '',
+              `**Status:** ❌ Failed (${reason})`,
+              '',
+              '---',
+              `*[View session](/sessions/${sessionId})*`,
+            ].join('\n');
+          }
+
+          updateComment(
+            { auth: githubAuth },
+            event.installationId,
+            owner,
+            repo,
+            prCommentId,
+            body,
+          ).catch((err: unknown) => {
+            createLogger('github').error('Failed to update PR comment', {
+              sessionId,
+              error: String(err),
+            });
+          });
+          return;
+        }
+
+        // For mentions, post a new comment with results
         const resultBody =
           session.status === 'completed'
             ? ((session.output as string) ?? session.stdout ?? 'Agent completed with no output.')
diff --git a/apps/control-plane/src/routes/auth.ts b/apps/control-plane/src/routes/auth.ts
index 2801bb0..c0bf5bb 100644
--- a/apps/control-plane/src/routes/auth.ts
+++ b/apps/control-plane/src/routes/auth.ts
@@ -41,7 +41,9 @@ export function createAuthRoutes(adminDeps?: AuthRouteDeps) {
             adminDeps.promoteToAdmin(auth.email);
             log.info('First OIDC user promoted to admin', { email: auth.email });
           }
-        } catch { /* auth not ready yet */ }
+        } catch {
+          /* auth not ready yet */
+        }
       }
       return response;
     } catch (err) {
@@ -51,13 +53,21 @@ export function createAuthRoutes(adminDeps?: AuthRouteDeps) {
   });
 
   app.get('/auth/logout', async (c) => {
-    try { await revokeSession(c); } catch { /* ignore */ }
+    try {
+      await revokeSession(c);
+    } catch {
+      /* ignore */
+    }
     deleteCookie(c, 'oidc-auth', { path: '/' });
     return c.redirect('/');
   });
 
   app.post('/auth/logout', async (c) => {
-    try { await revokeSession(c); } catch { /* ignore */ }
+    try {
+      await revokeSession(c);
+    } catch {
+      /* ignore */
+    }
     deleteCookie(c, 'oidc-auth', { path: '/' });
     return c.redirect('/');
   });
diff --git a/packages/integrations/src/callback.test.ts b/packages/integrations/src/callback.test.ts
index a190264..6701d8a 100644
--- a/packages/integrations/src/callback.test.ts
+++ b/packages/integrations/src/callback.test.ts
@@ -1,5 +1,5 @@
 import { describe, test, expect, vi, beforeEach } from 'vitest';
-import { postComment } from './callback.js';
+import { postComment, updateComment } from './callback.js';
 import type { CallbackDeps } from './callback.js';
 
 const mockAuth = {
@@ -16,20 +16,22 @@ beforeEach(() => {
 });
 
 describe('postComment', () => {
-  test('posts comment successfully', async () => {
+  test('posts comment and returns comment ID', async () => {
     const mockFetch = vi.fn().mockResolvedValue({
       ok: true,
       status: 201,
+      json: async () => ({ id: 42 }),
     });
     globalThis.fetch = mockFetch as unknown as typeof fetch;
 
-    await postComment(
+    const commentId = await postComment(
       deps,
       12345,
       'https://api.github.com/repos/org/repo/issues/42',
       'Session completed successfully.',
     );
 
+    expect(commentId).toBe(42);
     expect(mockFetch).toHaveBeenCalledOnce();
     expect(mockFetch).toHaveBeenCalledWith(
       'https://api.github.com/repos/org/repo/issues/42/comments',
@@ -62,3 +64,42 @@ describe('postComment', () => {
   // The retry logic is tested implicitly by the non-retryable error test above.
   // TODO: re-enable when bun test supports async timer advancement.
 });
+
+describe('updateComment', () => {
+  test('updates comment successfully via PATCH', async () => {
+    const mockFetch = vi.fn().mockResolvedValue({
+      ok: true,
+      status: 200,
+    });
+    globalThis.fetch = mockFetch as unknown as typeof fetch;
+
+    await updateComment(deps, 12345, 'org', 'repo', 99, 'Updated body');
+
+    expect(mockFetch).toHaveBeenCalledOnce();
+    expect(mockFetch).toHaveBeenCalledWith(
+      'https://api.github.com/repos/org/repo/issues/comments/99',
+      expect.objectContaining({
+        method: 'PATCH',
+        headers: expect.objectContaining({
+          Authorization: 'Bearer ghs_test_token',
+        }),
+        body: JSON.stringify({ body: 'Updated body' }),
+      }),
+    );
+  });
+
+  test('throws on non-retryable error (404)', async () => {
+    const mockFetch = vi.fn().mockResolvedValue({
+      ok: false,
+      status: 404,
+      text: async () => 'not found',
+    });
+    globalThis.fetch = mockFetch as unknown as typeof fetch;
+
+    await expect(updateComment(deps, 12345, 'org', 'repo', 99, 'body')).rejects.toThrow(
+      'GitHub comment update failed: 404 not found',
+    );
+
+    expect(mockFetch).toHaveBeenCalledOnce();
+  });
+});
diff --git a/packages/integrations/src/callback.ts b/packages/integrations/src/callback.ts
index da4a0c1..1d0a077 100644
--- a/packages/integrations/src/callback.ts
+++ b/packages/integrations/src/callback.ts
@@ -4,13 +4,19 @@ export interface CallbackDeps {
   auth: GitHubAuth;
 }
 
-/** Post a comment on a GitHub issue/PR */
+const GITHUB_HEADERS = {
+  Accept: 'application/vnd.github+json',
+  'Content-Type': 'application/json',
+  'X-GitHub-Api-Version': '2022-11-28',
+} as const;
+
+/** Post a comment on a GitHub issue/PR. Returns the comment ID. */
 export async function postComment(
   deps: CallbackDeps,
   installationId: number,
   issueUrl: string,
   body: string,
-): Promise<void> {
+): Promise<number> {
   const token = await deps.auth.getInstallationToken(installationId);
   const commentsUrl = `${issueUrl}/comments`;
 
@@ -20,14 +26,15 @@ export async function postComment(
       method: 'POST',
       headers: {
         Authorization: `Bearer ${token}`,
-        Accept: 'application/vnd.github+json',
-        'Content-Type': 'application/json',
-        'X-GitHub-Api-Version': '2022-11-28',
+        ...GITHUB_HEADERS,
       },
       body: JSON.stringify({ body }),
     });
 
-    if (res.ok) return;
+    if (res.ok) {
+      const json = (await res.json()) as { id: number };
+      return json.id;
+    }
 
     if (res.status === 403 || res.status === 429) {
       lastError = new Error(`GitHub API ${res.status}: ${await res.text()}`);
@@ -40,3 +47,40 @@ export async function postComment(
 
   throw lastError ?? new Error('Failed to post comment after retries');
 }
+
+/** Update an existing comment by ID */
+export async function updateComment(
+  deps: CallbackDeps,
+  installationId: number,
+  owner: string,
+  repo: string,
+  commentId: number,
+  body: string,
+): Promise<void> {
+  const token = await deps.auth.getInstallationToken(installationId);
+  const url = `https://api.github.com/repos/${owner}/${repo}/issues/comments/${commentId}`;
+
+  let lastError: Error | null = null;
+  for (let attempt = 0; attempt < 3; attempt++) {
+    const res = await fetch(url, {
+      method: 'PATCH',
+      headers: {
+        Authorization: `Bearer ${token}`,
+        ...GITHUB_HEADERS,
+      },
+      body: JSON.stringify({ body }),
+    });
+
+    if (res.ok) return;
+
+    if (res.status === 403 || res.status === 429) {
+      lastError = new Error(`GitHub API ${res.status}: ${await res.text()}`);
+      await new Promise((r) => setTimeout(r, (attempt + 1) * 2000));
+      continue;
+    }
+
+    throw new Error(`GitHub comment update failed: ${res.status} ${await res.text()}`);
+  }
+
+  throw lastError ?? new Error('Failed to update comment after retries');
+}
diff --git a/packages/integrations/src/index.ts b/packages/integrations/src/index.ts
index 0db63a5..6524176 100644
--- a/packages/integrations/src/index.ts
+++ b/packages/integrations/src/index.ts
@@ -3,7 +3,7 @@ export { createGitHubAuth } from './github-auth.js';
 export type { GitHubAuth } from './github-auth.js';
 export { matchDaemon } from './router.js';
 export type { MatchResult } from './router.js';
-export { postComment } from './callback.js';
+export { postComment, updateComment } from './callback.js';
 export type { CallbackDeps } from './callback.js';
 export type { GitHubEvent, GitHubAppConfig, GitHubDaemon } from './types.js';
 export {