Express GitHub Issue triage agent

An AI agent that triages new GitHub issues. When an issue is opened, a GitHub webhook calls this Express app, the AI SDK classifies the issue, and the agent applies labels and posts a maintainer reply. It deploys to Vercel as a single function with zero configuration and no database.

How it works

GitHub issue opened
  → POST /api/webhooks/github   (signature verified)
  → 202 acknowledged immediately
  → waitUntil: generateObject (AI SDK) classifies the issue
  → Octokit applies labels + posts a reply
     (on failure: labels the issue `needs-triage` instead of failing silently)

The app is stateless, and each issue is triaged independently from its webhook payload. Issues the model classifies as spam are labeled but don't get a reply.

Before you deploy

Have these three values ready. The deploy step sets them as environment variables.

AI_GATEWAY_API_KEY, a Vercel AI Gateway key. The default model, anthropic/claude-haiku-4.5, runs on the free tier.
GITHUB_TOKEN, a fine-grained token with Issues: Read and write on the repository you want triaged.
GITHUB_WEBHOOK_SECRET, any random string you choose now. You give the same value to Vercel here and to GitHub when you create the webhook.

Deploy

Click Deploy, then paste the three values above when Vercel prompts for environment variables.

Prefer the command line? Clone the repo, run npm install, then vercel --prod with the Vercel CLI, and set the same three variables in the project's settings.

Either way, Vercel builds and returns a production URL like https://your-app.vercel.app.

Connect the webhook

In the repository you want triaged, go to Settings → Webhooks → Add webhook and set:

Payload URL: https://your-app.vercel.app/api/webhooks/github
Content type: application/json
Secret: the same GITHUB_WEBHOOK_SECRET you set during deploy
Which events: choose Let me select individual events, then check only Issues

Open a new issue in that repository. Within a few seconds the agent labels it and posts a triage comment.

Local development

vercel dev

GitHub needs a public URL to deliver webhooks, so expose your local server with a tunnel (e.g. ngrok http 3000) and point the webhook's Payload URL at it while testing.

Project structure

File	Purpose
`src/index.ts`	Express app: verifies the webhook signature, filters for opened issues, runs triage in `waitUntil`
`src/triage.ts`	AI SDK `generateObject` call with a Zod schema for the triage decision
`src/github.ts`	Octokit calls to label the issue and post the reply, plus a `needs-triage` fallback
`vercel.json`	Vercel configuration

Customize

Reply tone and behavior: the classification and reply come entirely from the prompt in src/triage.ts, steered by each field's .describe() text. Edit the prompt to change the voice (formal, terse, technical), to require specifics like reproduction steps, or to follow your project's conventions.
Triage shape: edit the Zod schema in src/triage.ts to change the fields the model returns.
Model: change the model string in src/triage.ts to any model the AI Gateway supports.
Skip the Gateway: to use a provider key directly (no Vercel AI billing), npm install @ai-sdk/anthropic, import it, set model: anthropic('claude-haiku-4-5'), and set ANTHROPIC_API_KEY instead of AI_GATEWAY_API_KEY.
More events: subscribe to additional webhook events on GitHub and register another handler, e.g. webhooks.on('pull_request.opened', ...), in src/index.ts.