nomos-slack-mcp

An MCP server that lets AI agents read and write Slack messages as you — not as a bot. Messages, reactions, and status updates appear exactly as if you typed them yourself.

Built for Claude Code and any MCP-compatible client. Supports multiple Slack workspaces with independent authentication.

Existing Slack integrations send messages as a bot with an APP badge. This uses Slack user tokens (xoxp-) so your agent operates as you — indistinguishable from you being at the keyboard.

• Send as you — no bot badge, no "APP" indicator
• Multi-workspace — manage 2+ Slack workspaces with separate tokens and permissions
• 10 tools — read, write, search, react, set status
• Smart resolution — use #channel-name, @username, or raw channel IDs
• Local only — tokens stay on your machine at ~/.nomos/slack/config.json with 0600 permissions

For each workspace you want to connect:

1. Go to api.slack.com/apps → Create New App → From app manifest
2. Paste the contents of `slack-app-manifest.yml` (or use the JSON version)
3. Click Create
4. Go to Install App → Install to Workspace → Allow

> [!TIP] > The manifest pre-configures all required User Token Scopes and the OAuth redirect URL. No manual scope configuration needed.

git clone https://github.com/project-nomos/nomos-slack-mcp.git
cd nomos-slack-mcp
pnpm install
pnpm build

Option A: OAuth flow (recommended)

pnpm add-workspace

You'll be prompted for:

• A workspace alias (e.g. work, side-project)
• Your Slack App's Client ID and Client Secret (found under Basic Information in your Slack App settings)

The script opens your browser for OAuth authorization and stores the user token automat