slack-mcp

slack-mcp

Multi-workspace Slack MCP server with draft+confirm safety, vault auto-export, and triple-mode auth.

One process, N workspaces, every write goes through draft → confirm. Built because the existing Slack MCP servers are single-workspace per instance and the Anthropic reference impl was deprecated.

Why use this over the alternatives

Install

Open Claude Code, paste:

/plugin marketplace add adelaidasofia/slack-mcp
/plugin install slack-mcp@slack-mcp

Then fill in tokens in .env (see SETUP.md for cookie extraction walkthrough).

git clone https://github.com/adelaidasofia/slack-mcp.git ~/.claude/slack-mcp
cd ~/.claude/slack-mcp
pip3 install --break-system-packages -r requirements.txt
cp .env.example .env
# fill in tokens — see SETUP.md for cookie extraction walkthrough

{
  "mcpServers": {
    "slack": {
      "command": "python3",
      "args": ["-m", "slack_mcp.server"],
      "cwd": "/Users/YOU/.claude/slack-mcp"
    }
  }
}

Tools (v0.1.1)

Meta: list_workspaces, healthcheck

Read: list_channels, search_channels, read_channel, read_thread, list_users, search_users, get_user_profile, search_messages

Write (draft+confirm): send_message → confirm_send, send_reply_quote → confirm_send, update_own_message → confirm_send, cancel_draft

Write (low-consequence, immediate): add_reaction, mark_read, delete_own_message

Auth modes

Cookie extraction takes ~3 minutes per workspace. See SETUP.md.

Vault auto-export

Every read_channel call mirrors the channel to <vault>/🤖 AI Chats/Slack/<workspace>/<channel>.md. Idempotent (same channel + day overwrites cleanly). Disable via SLACK_MCP_VAULT_EXPORT=false.

Configuration

All config via env vars (loaded from .env at process start):

• SLACK_WORKSPACES — comma-separated list of aliases (e.g. onde,mycelium)
• SLACK_PRIMARY_WORKSPACE — default workspace when tool calls omit workspace
• Per-workspace: SLACK_WORKSPACE_<ALIAS>_TYPE, _TOKEN, _COOKIE (xoxc only), _TEAM_ID, _LABEL
• SLACK_MCP_VAULT_PATH — vault root for the auto-export mirror (default ~/Documents/Vault)
• SLACK_MCP_VAULT_EXPORT — true/false (default true)
• SLACK_MCP_AUDIT_LOG_PATH — JSONL audit log path
• SLACK_MCP_DRAFT_TTL_SECONDS — draft expiration (default 3600)
• SLACK_MCP_SCRUB_PROMPT_INJECTION — true/false (default true)

Safety patterns