| name | slack-file |
| description | Download Slack attachments by file ID, or upload local files into a Slack thread. Use when a Slack message lists Files: whose contents matter, or when posting a file to Slack; the MCP connector reports metadata only. Guides Keychain token setup if missing. |
Slack file
The Slack MCP connector reports attachment metadata only. This skill's script is the download and upload path. Other skills that need Slack file bytes follow this skill.
macOS. The token lives in the Keychain (service slack-files-token); the script reads it. Do not print, echo, or pass the token — including via security … -w.
1. Ready
From this skill's directory (the folder that contains this SKILL.md):
scripts/slack-file is executable.- Keychain has the service, metadata only:
security find-generic-password -s slack-files-token (no -w).
jq and curl are on PATH.
If 2 fails: give the user Setup below and stop. Do not store the token yourself.
The sandbox cannot read the Keychain or reach slack.com — run the script with those allowed.
Done when: every check passes, or the run has stopped for setup.
2. Run
File IDs come from slack_read_thread as Files: name.png (ID: F012SSD0KK8, image/png, 393.6 KB).
Download — prints local paths; then Read them:
scripts/slack-file -d <dir> FILE_ID [FILE_ID ...]
Upload — slack_send_message is text-only; this posts the files. Prints the new file IDs:
scripts/slack-file up -c CHANNEL_ID [-t THREAD_TS] [-m COMMENT] FILE [FILE ...]
If the command fails: ask the user to paste or upload each file. Stop if they decline.
Done when: every requested file is a local path (download) or a printed file ID (upload), or the run has stopped.
Setup
A Slack app with files:read (and files:write to upload). The Blockscout workspace: Files Reader.
Then the user stores the token themselves:
security add-generic-password -a "$USER" -s slack-files-token
It prompts. Already exists: add -U. jq: brew install jq.
