Slack

Slack API Skill

Overview

Slack APIs enable custom apps, bots, and slash commands. This skill covers the @slack/web-api and @slack/bolt frameworks.

Installation

npm install @slack/bolt
pip install slack_bolt

Authentication

Uses Bot User OAuth Tokens (xoxb-) for sending messages, and Signing Secrets to verify incoming requests from Slack.

Core Concepts

• Block Kit: A JSON-based UI framework for building rich messages.
• Events API: Webhooks for real-time Slack activity.
• Conversations: Channels, DMs, or Private Groups.

Common Workflows

1. Initialize Bolt App with token and signing secret.
2. Use app.message() to listen to text.
3. Use app.client.chat.postMessage to send messages.

Error Handling

Catch WebAPIPlatformError. Check error.data.error (e.g., channel_not_found, not_in_channel).

Security

You MUST verify the signature of incoming Slack requests using your Signing Secret. The Bolt framework does this automatically.

Rate Limits

Tier 1 endpoints are 1 request per second. Tier 4 endpoints (like chat.postMessage) are 1 request per second per channel.

Best Practices

Use Block Kit Builder to design UIs. Store state in your database rather than trying to pass complex state through Slack modal private_metadata.

Troubleshooting

If your app can't post to a channel, ensure you have invited the bot to the channel first.

References

• API Reference

Why use this skill

Use this when your agent works with slack — structured patterns beat pasted docs and prevent common hallucinations.

AI pitfalls

• Using outdated SDK or API versions from training data
• Inventing environment variable names
• Omitting error handling and retry logic

Production checklist

• Secrets in environment variables, not source code
• Error handling and logging in place
• Rate limits and timeouts configured

Related skills

• github-actions — integrates with
• sentry — integrates with

Last Verified: 2026-07-02