dsh-slack-mcp

A local, keyring-backed Slack MCP server for DSH / Codex. It keeps the pinned upstream package (@nrjdalal/slack-mcp-server) unchanged and layers a small set of conversation and workflow tools on top.

The Slack credential never lives in config, environment files, or the repo: a small Go launcher reads a user token (xoxp-…) from the Secret Service and passes it to the Node server through the child environment.

Layout

launcher/          Go launcher: keyring → exec node server.mjs
server.mjs         MCP server assembly (upstream server + extensions)
conversations.mjs  conversation tools (info/members/invite/open/mark)
workflows.mjs      workflow tools (featured list / webhook start)
slack-api.mjs      Slack call wrapper with a public error allowlist
test/              node:test suites

Related MCP server: Slack MCP Server

Tools

The upstream package contributes the ordinary Slack tools (chat_post_message, conversations_history, conversations_replies, conversations_list, conversations_unreads, conversations_mark, search_messages, reactions, files). A deployment that fronts this server with the shared gateway filters that catalog through its own allowlist (shared/policy.mjs in the gateway), so enabling conversations_mark there is a policy change, not a code change. Setting SLACK_MCP_ALLOW_WRITE=false (or 0) omits every write tool.

Requirements

• Node.js 20+

• Go 1.22+ (launcher only)

• A Slack app user token with: channels:history groups:history im:history mpim:history channels:read groups:read im:read mpim:read search:read files:read channels:write groups:write im:write mpim:write chat:write reactions:write channels:write.invites groups:write.invites

• zod and the two pinned packages from package.json

conversations_mark needs the same *:write scopes; it does not need stars:* or reminders:*. It requires an explicit ts (fetch the latest via conversations_history with limit: 1 first).

Install

npm ci
go build -o ~/.local/bin/dsh-slack-mcp ./launcher

Store the token once (stdin only, never an argument):

secret-tool store --label='Slack user token' \
  service donut-slack-task-dispatcher username slack-user-token

The launcher reads exactly that service/username pair, rejects anything that is not an xoxp- token, and refuses to start if server.mjs is missing.

MCP client configuration

[mcp_servers.slack-local]
command = "/home/you/.local/bin/dsh-slack-mcp"

The process speaks MCP over stdio and logs one line to stderr on startup.

Tests

npm test

The suites use an in-memory transport and a fake Slack caller; no network call is made and no token is required.

Security notes

• The token is read from Secret Service at launch and passed only through the child environment; it is never written to disk by this project.

• Slack error payloads are reduced to a public allowlist. Raw SDK errors, headers, and tokens are never returned to the model.

• Writes are single-shot: a transport failure reports outcome_unknown instead of replaying the request. Read back state before retrying.

• workflow_webhook_start performs one POST to a preconfigured webhook URL stored in Secret Service under service=codex-slack-mcp-workflows. An accepted trigger is not a completed workflow.