Slack

Quick start

Always invoke through bash {baseDir}/scripts/invoke.sh — never call mcporter directly. The wrapper seeds the OAuth vault from the env-supplied tokens when needed, then calls mcporter.

bash {baseDir}/scripts/invoke.sh call maverick-slack.search_messages query="launch"
bash {baseDir}/scripts/invoke.sh call maverick-slack.conversations_list
bash {baseDir}/scripts/invoke.sh call maverick-slack.users_list

For structured output (also surfaces transport errors as JSON envelopes — workaround for mcporter #153):

bash {baseDir}/scripts/invoke.sh call --output json maverick-slack.search_messages query="launch" | jq '.result.content'

Discover available tools and schemas:

bash {baseDir}/scripts/invoke.sh list maverick-slack --schema

Safety

Write operations (chat_postMessage, canvas edits, replies, message updates, and other externally visible Slack changes) modify Slack content visible to the connected workspace. Confirm clear user intent before invoking write tools — search and read tools are safe to call freely while exploring. Show the exact composed message and get confirmation before posting, and never post to a channel the user has not explicitly named.

Authentication

Tokens are provisioned and rotated automatically. If a call returns HTTP 401 that doesn't recover within a few seconds, the OAuth grant has been revoked — re-authorize the integration to refresh credentials.

Data flow

Tool calls travel to Slack's hosted MCP service at https://mcp.slack.com/mcp over HTTPS, authenticated via OAuth. Slack sees the message, channel, thread, canvas, and user data referenced by each call. Use this skill for Slack-related work only; do not pass unrelated sensitive content through these tools.

Dependencies

• mcporter (github.com/steipete/mcporter) — MCP CLI used to invoke Slack's hosted MCP server. Auto-installed via npm install -g --ignore-scripts mcporter if missing on PATH (see install spec in frontmatter). The install spec uses unpinned mcporter (npm latest); operators with strict supply-chain controls should override the install to pin a specific version (e.g. mcporter@\x3Cversion>).
• jq (stedolan.github.io/jq) — JSON processor used by the vault initializer. System dependency; install via your OS package manager (apt install jq, brew install jq, etc.).
• flock (part of util-linux) — file locking used to serialize concurrent vault writes. Available by default on Linux; on macOS install via brew install flock.
• shasum (Perl, ships with Digest::SHA) — computes the SHA-256 hashes used to derive the mcporter vault key and the provisioned-token marker. Preinstalled on macOS and on Debian/Ubuntu (incl. the deployed cloudflare/sandbox Ubuntu 22.04 image); on minimal Linux images install perl-Digest-SHA. The script invokes shasum -a 256 rather than GNU sha256sum so it runs on stock macOS without coreutils.