diff --git a/Dockerfile b/Dockerfile
new file mode 100644
index 0000000..74b8045
--- /dev/null
+++ b/Dockerfile
@@ -0,0 +1,18 @@
+FROM node:22-bookworm-slim AS build
+
+WORKDIR /workspace
+RUN corepack enable
+COPY package.json pnpm-lock.yaml pnpm-workspace.yaml tsconfig.base.json ./
+COPY packages ./packages
+RUN pnpm install --frozen-lockfile
+RUN pnpm build:packages
+
+FROM node:22-bookworm-slim
+
+WORKDIR /workspace
+RUN apt-get update && apt-get install --yes --no-install-recommends git && rm -rf /var/lib/apt/lists/*
+COPY --from=build /workspace /workspace
+ENV NODE_ENV=production
+ENV PORT=3000
+EXPOSE 3000
+CMD ["node", "packages/github-app/dist/server.js"]
diff --git a/docs/github-app-manifest.json b/docs/github-app-manifest.json
new file mode 100644
index 0000000..873666a
--- /dev/null
+++ b/docs/github-app-manifest.json
@@ -0,0 +1,19 @@
+{
+  "name": "CodeDecay",
+  "description": "Deterministic CodeDecay pull-request safety analysis.",
+  "url": "https://github.com/SubmuxHQ/CodeDecay",
+  "hook_attributes": {
+    "url": "https://codedecay-github-app-1093061541451.us-central1.run.app/github/webhooks",
+    "active": true
+  },
+  "redirect_url": "https://github.com/SubmuxHQ/CodeDecay",
+  "public": false,
+  "default_permissions": {
+    "metadata": "read",
+    "contents": "read",
+    "pull_requests": "read",
+    "issues": "write",
+    "checks": "write"
+  },
+  "default_events": ["pull_request"]
+}
diff --git a/docs/github-app.md b/docs/github-app.md
index 956dbfc..f66600c 100644
--- a/docs/github-app.md
+++ b/docs/github-app.md
@@ -21,14 +21,15 @@ For the first hosted version, the app only runs deterministic PR analysis. It
 does not run project commands, deployment commands, LLM calls, model calls, or
 CodeDecayCloud services.
 
-## GitHub App settings
+## Create the GitHub App
 
 Create a GitHub App in the GitHub organization that will own the hosted app.
 
-Set the webhook URL to:
+Create the App from [`github-app-manifest.json`](./github-app-manifest.json) in
+the GitHub App creation flow. Its webhook URL is the Cloud Run service URL:
 
 ```text
-https://<render-service-host>/github/webhooks
+https://codedecay-github-app-1093061541451.us-central1.run.app/github/webhooks
 ```
 
 Subscribe to these events:
@@ -45,23 +46,43 @@ Use these repository permissions:
 
 The Issues permission is required because GitHub PR comments use the Issues API.
 
-## Render deployment
+## Google Cloud Run deployment
 
-Create a Render Web Service connected to this repository.
+The service is designed for Cloud Run in project
+`project-7279e7f9-46cf-49d4-bbd`, region `us-central1`. Store each required
+value in Secret Manager, never in a repository, command history, or GitHub
+Actions secret.
 
-Build command:
+Create the secret containers, then add values from local files. Keep the
+private key and webhook secret out of shell history and source control:
 
 ```bash
-pnpm install --frozen-lockfile && pnpm --filter @submuxhq/codedecay-github-app build
+gcloud secrets create codedecay-github-app-id
+gcloud secrets create codedecay-github-app-private-key
+gcloud secrets create codedecay-github-app-webhook-secret
+gcloud secrets versions add codedecay-github-app-id --data-file=app-id.txt
+gcloud secrets versions add codedecay-github-app-private-key --data-file=private-key.pem
+gcloud secrets versions add codedecay-github-app-webhook-secret --data-file=webhook-secret.txt
 ```
 
-Start command:
+Deploy the reviewed commit with Cloud Run. Keep a single instance during the
+staging rollout so duplicate webhook handling cannot race across instances.
 
 ```bash
-pnpm --filter @submuxhq/codedecay-github-app start
+gcloud run deploy codedecay-github-app \
+  --project=project-7279e7f9-46cf-49d4-bbd \
+  --region=us-central1 \
+  --source=. \
+  --allow-unauthenticated \
+  --min-instances=1 \
+  --max-instances=1 \
+  --memory=1Gi \
+  --cpu=1 \
+  --set-env-vars=NODE_ENV=production,GITHUB_WEBHOOK_PATH=/github/webhooks \
+  --set-secrets=GITHUB_APP_ID=codedecay-github-app-id:latest,GITHUB_PRIVATE_KEY=codedecay-github-app-private-key:latest,GITHUB_WEBHOOK_SECRET=codedecay-github-app-webhook-secret:latest
 ```
 
-Required environment variables:
+Cloud Run receives these required environment variables from Secret Manager:
 
 ```text
 GITHUB_APP_ID=<numeric app id>
diff --git a/packages/github-app/src/github/comments.ts b/packages/github-app/src/github/comments.ts
index 8a9b5ae..8dc4a5c 100644
--- a/packages/github-app/src/github/comments.ts
+++ b/packages/github-app/src/github/comments.ts
@@ -33,12 +33,20 @@ async function findExistingComment(
   octokit: GitHubClient,
   target: GitHubTarget
 ): Promise<GitHubComment | undefined> {
-  const response = await octokit.rest.issues.listComments({
-    owner: target.owner,
-    repo: target.repo,
-    issue_number: target.pullNumber,
-    per_page: 100
-  });
+  for (let page = 1; page <= 10; page += 1) {
+    const response = await octokit.rest.issues.listComments({
+      owner: target.owner,
+      repo: target.repo,
+      issue_number: target.pullNumber,
+      per_page: 100,
+      page
+    });
+
+    const existing = response.data.find((comment) => comment.body?.includes(COMMENT_MARKER));
+    if (existing || response.data.length < 100) {
+      return existing;
+    }
+  }
 
-  return response.data.find((comment) => comment.body?.includes(COMMENT_MARKER));
+  return undefined;
 }
diff --git a/packages/github-app/src/server.ts b/packages/github-app/src/server.ts
index e14c4c9..d67194d 100644
--- a/packages/github-app/src/server.ts
+++ b/packages/github-app/src/server.ts
@@ -24,8 +24,10 @@ createServer((request, response) => {
   }
 
   void Promise.resolve(middleware(request, response)).catch((error: unknown) => {
+    const message = error instanceof Error ? error.message : String(error);
+    process.stderr.write(`CodeDecay GitHub App request failed: ${message}\n`);
     response.writeHead(500, { "content-type": "application/json" });
-    response.end(JSON.stringify({ ok: false, error: error instanceof Error ? error.message : String(error) }));
+    response.end(JSON.stringify({ ok: false, error: "Internal server error" }));
   });
 }).listen(port, () => {
   process.stdout.write(`CodeDecay GitHub App listening on port ${port} at ${webhooksPath}\n`);
diff --git a/packages/github-app/test/github-app.test.ts b/packages/github-app/test/github-app.test.ts
index 4eb0ab0..5dec0f7 100644
--- a/packages/github-app/test/github-app.test.ts
+++ b/packages/github-app/test/github-app.test.ts
@@ -80,6 +80,26 @@ describe("CodeDecay GitHub App", () => {
     expect(octokit.rest.issues.createComment).not.toHaveBeenCalled();
   });
 
+  it("finds a marker comment beyond the first page", async () => {
+    const octokit = createOctokit();
+    const firstPage = Array.from({ length: 100 }, (_, index) => ({ id: index + 1, body: "other comment" }));
+    vi.mocked(octokit.rest.issues.listComments)
+      .mockResolvedValueOnce({ data: firstPage })
+      .mockResolvedValueOnce({ data: [{ id: 101, body: `${COMMENT_MARKER}\nOld report` }] });
+
+    await upsertPullRequestComment({
+      octokit,
+      target: { owner: "SubmuxHQ", repo: "CodeDecay", pullNumber: 12, headSha: "head-sha" },
+      markdown: "## New report"
+    });
+
+    expect(octokit.rest.issues.listComments).toHaveBeenNthCalledWith(
+      2,
+      expect.objectContaining({ page: 2 })
+    );
+    expect(octokit.rest.issues.updateComment).toHaveBeenCalledWith(expect.objectContaining({ comment_id: 101 }));
+  });
+
   it("marks the check run as failed when analysis fails", async () => {
     const context = createContext();
     const cleanup = vi.fn();