Add Resend email agent with Slack approval example

README.md

@@ -48,6 +48,7 @@ For information on how to run each project, see the README in each directory.
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+| [Resend email agent with Slack approval](/resend-slack-email-agent)                                        | An AI agent that drafts replies to a [Resend](https://resend.com) inbox and asks you in Slack before sending. Uses [hosted webhooks](https://trigger.dev/docs/webhooks) for Resend and Slack, and [wait tokens](https://trigger.dev/docs/wait-for-token) to pause each email thread until you click Send |
 | [Remix webhooks](/remix-webhooks)                                                                          | Example of triggering tasks from incoming webhooks in a [Remix app](https://remix.run/) with Trigger.dev                                                                                                                                                                                                                                                                                                                             |
 | [Supabase edge functions](/supabase-edge-functions)                                                        | Learn how to trigger tasks from [Supabase Edge Functions](https://supabase.com/docs/guides/functions) and Database changes                                                                                                                                                                                                                                                                                                           |
 | [Vercel AI SDK image generator](/vercel-ai-sdk-image-generator)                                            | Generate images using [OpenAI DALL-E](https://openai.com/dall-e) models with Vercel's [AI SDK](https://sdk.vercel.ai/docs/introduction) and Trigger.dev                                                                                                                                                                                                                                                                              |

resend-slack-email-agent/.env.example

@@ -0,0 +1,21 @@
+# Your Trigger.dev project ref (from the project settings page in the dashboard)
+TRIGGER_PROJECT_REF=proj_xxxxxxxxxxxxxxxxxxxxxxxx
+
+# Resend API key with access to Inboxes (reads threads, sends replies)
+RESEND_API_KEY=re_xxxxxxxxxxxxxxxxxxxxxxxx
+
+# Slack app's Bot User OAuth Token
+SLACK_BOT_TOKEN=xoxb-xxxxxxxxxxxxxxxxxxxxxxxx
+
+# The one Slack user the bot DMs and listens to (Slack profile > ... > Copy member ID)
+SLACK_USER_ID=U0123456789
+
+# Vercel AI Gateway key, used by the AI SDK to draft replies
+AI_GATEWAY_API_KEY=
+
+# Only emails from these sender domains get drafted (comma-separated).
+# Leave empty to draft a reply to every email.
+ALLOWED_SENDER_DOMAINS=yourcompany.com
+
+# Optional: a different AI Gateway model id
+# INBOX_BOT_MODEL=anthropic/claude-opus-5.5

resend-slack-email-agent/.gitignore

@@ -0,0 +1,5 @@
+node_modules
+.env
+.env*
+!.env.example
+.trigger

resend-slack-email-agent/README.md

@@ -0,0 +1,37 @@
+# Resend email agent with Slack approval
+
+An AI agent that drafts replies to the email in a [Resend Inboxes](https://resend.com/docs/api-reference/inboxes) inbox and sends nothing until you approve it in Slack.
+
+Every email chain becomes its own thread in your DMs with the bot. The agent drafts a reply and posts it with **Send** and **Don't send** buttons. To change a draft, reply in the thread ("shorter", "say we're closed over Christmas") and it writes a new one. Later emails in the same chain land in the same Slack thread, with a new draft.
+
+## How it works
+
+Each email chain gets one long-running [Trigger.dev](https://trigger.dev) run that sleeps on a [wait token](https://trigger.dev/docs/wait-for-token) between events. The token is tagged with the email thread id and the Slack message timestamp, so a webhook from either side can find it and wake the run. A waiting run holds no machine and no concurrency slot, so a draft can wait days for your click.
+
+- `src/trigger/endpoints.ts`: the two hosted webhook endpoints, one for Resend and one for Slack. Trigger.dev checks each request's signature before your code runs.
+- `src/trigger/email-thread.ts`: one run per email chain. It posts the email to Slack, drafts a reply, creates a wait token and waits on it. A click sends or drops the draft, a thread reply redrafts it, and a new email posts and redrafts. After 30 quiet days the run ends; the next email starts a new run in the same Slack thread.
+- `src/trigger/inbound.ts`: the webhook tasks. A new email wakes the chain's run, or starts one. Slack thread replies and button clicks complete the waiting token.
+- `src/trigger/draft.ts`: the drafting prompt, using the [AI SDK](https://ai-sdk.dev) through the Vercel AI Gateway. Tune `SYSTEM_PROMPT` for your inbox.
+- `src/trigger/resend.ts` and `src/trigger/slack.ts`: thin API clients.
+
+What keeps it safe:
+
+- **A person sends every reply.** The model has no tools, so a hostile email can only change the words of a draft you read first.
+- **Email text is escaped** before it goes into Slack, so an email can't @-mention anyone or disguise a link.
+- **Only you can act.** The Slack app is DM-only, and clicks or replies from anyone other than `SLACK_USER_ID` are ignored.
+- **Senders can be filtered.** `ALLOWED_SENDER_DOMAINS` stops unknown senders before they reach Slack or cost a model call.
+- **Sends are idempotent.** A retried attempt reuses the same Resend idempotency key, so nobody gets a reply twice.
+
+Hosted webhooks are in public beta. The packages are pinned to the `4.8.0-webhooks` beta release.
+
+## Setup
+
+You need a [Trigger.dev](https://cloud.trigger.dev) project, a Resend inbox on a verified domain, a Slack workspace where you can create apps, and a [Vercel AI Gateway](https://vercel.com/docs/ai-gateway) key.
+
+1. Copy `.env.example` to `.env` and set `TRIGGER_PROJECT_REF`, `RESEND_API_KEY`, `SLACK_USER_ID`, `AI_GATEWAY_API_KEY` and `ALLOWED_SENDER_DOMAINS`.
+2. Run `pnpm install` and `pnpm dev`. The `resend` and `slack` endpoints appear on your environment's **Webhooks** page with their URLs.
+3. **Resend:** add a webhook pointing at the `resend` endpoint URL with the `inbox.email.received` event. Paste its signing secret into the `resend` endpoint in the Trigger.dev dashboard.
+4. **Slack:** put the `slack` endpoint URL in both `request_url`s in `slack/manifest.yaml`, then create the app from it (**Create New App** > **From a manifest**). Paste the app's **Signing Secret** into the `slack` endpoint and click **Verify** in Slack's Event Subscriptions. Install the app and set `SLACK_BOT_TOKEN` (`xoxb-...`).
+5. Restart `pnpm dev` and send an email to your inbox.
+
+For production, run `pnpm run deploy`, set the same environment variables on the prod environment in the dashboard, and point Resend and Slack at the prod endpoint URLs.

resend-slack-email-agent/package.json

@@ -0,0 +1,28 @@
+{
+  "name": "resend-slack-email-agent",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "dev": "trigger dev",
+    "deploy": "trigger deploy",
+    "typecheck": "tsc --noEmit"
+  },
+  "dependencies": {
+    "@trigger.dev/sdk": "4.8.0-webhooks.20261020092920",
+    "@trigger.dev/slack": "4.8.0-webhooks.20261020092920",
+    "ai": "^7.0.143",
+    "zod": "^4.6.7"
+  },
+  "devDependencies": {
+    "@trigger.dev/build": "4.8.0-webhooks.20261020092920",
+    "@types/node": "^26.6.5",
+    "trigger.dev": "4.8.0-webhooks.20261020092920",
+    "typescript": "^5.9.3"
+  },
+  "packageManager": "pnpm@10.34.5",
+  "pnpm": {
+    "onlyBuiltDependencies": [
+      "esbuild"
+    ]
+  }
+}