How do I install the Slack File skill?

Run npx skillmds@latest add blockscout/slack-file in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Slack File safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Slack File?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Slack File free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Slack File?

blockscout (@blockscout) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Slack File by blockscout — Agent Skill

Name: Slack File
Author: blockscout

Slack File

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.

blockscout ec8d433 2 files · 6.3 KB Updated Sep 17, 2026

File contents

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.

---name: slack-filedescription: 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 fileThe 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. ReadyFrom **this skill's directory** (the folder that contains this `SKILL.md`):1. `scripts/slack-file` is executable.2. Keychain has the service, metadata only: `security find-generic-password -s slack-files-token` (no `-w`).3. `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. RunFile IDs come from `slack_read_thread` as `Files: name.png (ID: F012SSD0KK8, image/png, 393.6 KB)`.Download — prints local paths; then Read them:```bashscripts/slack-file -d <dir> FILE_ID [FILE_ID ...]```Upload — `slack_send_message` is text-only; this posts the files. Prints the new file IDs:```bashscripts/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.## SetupA Slack app with `files:read` (and `files:write` to upload). The Blockscout workspace: [Files Reader](https://blockscout.slack.com/marketplace/A0BMY22GBQR-files-reader).Then the user stores the token themselves:```bashsecurity add-generic-password -a "$USER" -s slack-files-token```It prompts. Already exists: add `-U`. `jq`: `brew install jq`.

Frequently asked questions