BYOA (Bring Your Own Agent) to Slack.

It should only take 10-15 minutes to get your agent responding to DMs and `@mentions in Slack.

1. Go to api.slack.com/apps to create a Slack app
2. Click "Create New App" and choose "From scratch"
3. Under OAuth & Permissions, add the following bot token scopes:
   • app_mentions:read
   • assistant:write
   • channels:history
   • chat:write
   • im:history
   • im:write
4. Install the app to your workspace (button under OAuth Tokens subsection)
5. Under App Home > Show Tabs > Chat Tab, check "Allow users to send Slash commands and messages from the chat tab"
6. Remix this val if you haven't already
7. Add your environment variables in your val sidebar:
   1. VAL_TOWN_API_TOKEN from Settings > API tokens
   2. SLACK_BOT_TOKEN in your Slack app: OAuth & Permissions > OAuth Tokens > Bot User OAuth Token
   3. SLACK_SIGNING_SECRET in your Slack app: from Basic Information > Signing Secret
   4. ANTHROPIC_API_KEY from the Anthropic console
8. Copy your HTTP url in events.ts (note: you can add a custom subdomain), then in your Slack app paste it under Event Subscriptions > Request URL
9. In your Slack app under Events Subscription > Enable Events > Subscribe to bot events, add app_mention, assistant_thread_started, and message.im

duck/
├── events.ts         # HTTP entry point (Hono app, Slack event router)
├── prompt.md         # System prompt for your agent
├── README.md
└── lib/
    ├── generate-response.ts         # AI core (Claude + MCP + web search)
    ├── handle-app-mention.ts        # Handles @mentions in channels and threads
    ├── handle-message.ts            # Handles DMs in assistant (Slack app) threads
    ├── handle-thread-started.ts     # Greeting + suggested prompts on new assistant thread
    └── slack-utils.ts               # Slack client and utils

This template uses Claude Sonnet 4.6 directly in lib/generate-response.ts, which requires setting an ANTHROPIC_API_KEY environment variable. Alternatively, you could use a gateway to switch between models easily, like the Vercel AI Gateway or the Kilo Gateway.

This agent comes with the following tools:

1. Anthropic web search
2. Val Town MCP server

You should of course edit and add your own tools! That's the whole point of BYOA :)

This val uses pinned imports (latest package version as of 2/19/26) to avoid breaking changes:

1. @slack/web-api@7.14.1
2. hono@4.12.0
3. ai@6.0.92
4. @ai-sdk/anthropic@3.0.45
5. @ai-sdk/mcp@1.0.21

It's "duck" as in rubber duck debugging. But you can call your agent whatever you'd like!

This val is based on Vercel's Slackbot Agent Guide, adapted for Val Town.