Slack Cli

Slack CLI

Use the Slack CLI to create, run, and manage Slack apps — including calling Web API methods directly and searching Slack developer documentation from the terminal.

For initial setup (sandbox creation, project scaffolding from templates), use the slack:create-slack-app skill instead.

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Step 1: Detect the Slack CLI

Resolve the path to the public Slack CLI before running any other command. We refer to the resolved value as SLACK_CMD — substitute it everywhere below. Try 1a → 1b → 1c in order; do not skip ahead.

1a. Standard install path (preferred — no verification needed)

The official install scripts place the binary at a fixed per-user path. If the file exists, use it directly: only the install script writes to that path.

• macOS / Linux: ~/.slack/bin/slack
• Windows: %USERPROFILE%\AppData\Local\slack-cli\bin\slack.exe (or %USERPROFILE%\.slack-cli\bin\slack.exe as a fallback)

POSIX shell:

[ -x "$HOME/.slack/bin/slack" ] && echo "$HOME/.slack/bin/slack"

PowerShell:

$p = "$env:USERPROFILE\AppData\Local\slack-cli\bin\slack.exe"
if (Test-Path $p) { $p } elseif (Test-Path "$env:USERPROFILE\.slack-cli\bin\slack.exe") { "$env:USERPROFILE\.slack-cli\bin\slack.exe" }

If a path is returned, set SLACK_CMD to that absolute path and proceed to Step 2. Do not also run _fingerprint.

1b. slack on PATH (verify with fingerprint)

If 1a found nothing, try slack on PATH:

slack _fingerprint 2>/dev/null

If it outputs d41d8cd98f00b204e9800998ecf8427e, set SLACK_CMD=slack and proceed.

1c. Ask about an alias, or install

If 1b fails or returns a different value, ask the developer using AskUserQuestion:

• "The slack command on your system doesn't appear to be the public Slack CLI. Do you have it installed under a different name or alias?"
• Options: "Yes, it's aliased as..." (let them provide the alias), "No, I need to install it"
• If they provide an alias, verify it with _fingerprint 2>/dev/null and set SLACK_CMD=.
• If they need to install it, run:

`` curl -fsSL https://downloads.slack-edge.com/slack-cli/install.sh | bash ` Then re-run **1a** — the install script will have written ~/.slack/bin/slack`.

Common mistakes: Don't use which slack to discover the binary — which resolves any shell alias and defeats the point of 1a. In Git Bash on Windows, use the POSIX probe form, not PowerShell.

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Step 2: Command Discovery via Help

Always run SLACK_CMD --help before constructing a command you have not used in the current session. Do not guess at flags — the help output is the source of truth.

• SLACK_CMD help — lists all available command groups
• SLACK_CMD --help — shows subcommands, flags, and usage examples

Resolving --app and --team values

When a command requires --app or --team:

• App ID: Run SLACK_CMD app list from the project directory to see installed apps and their IDs.
• Team ID: Run SLACK_CMD auth list to see authenticated workspaces and their team IDs.

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Step 3: Searching Documentation (slack docs search)

Search Slack's developer documentation directly from the terminal.

SLACK_CMD docs search "" --output=text --limit=5

Use --output=text for concise terminal-readable results. Use this:

• Before implementing a Slack feature you have not used before
• When the developer asks "how does X work in Slack?"
• To verify API behavior or required scopes
• To look up Block Kit elements, event types, or method parameters

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Step 4: Calling Web API Methods (slack api)

Call any Slack Web API method directly. Run SLACK_CMD api --help for full details and examples.

Parameters are passed as positional key=value pairs (NOT --key=value flags):

SLACK_CMD api chat.postMessage channel=C0123456789 text="Hello from the CLI"

Important distinction: --team, --token, --json, and --data are meta-flags (prefixed with --). API method parameters use positional key=value syntax without dashes.

Reference: Full method list at https://docs.slack.dev/reference/methods.md.

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Step 5: Authentication (slack auth)

When to run this flow

Slack auth is per-team, not a single boolean. Run the seamless login flow below whenever any of these is true:

• The developer is not authenticated to any team yet.
• The developer wants to add a new team / workspace / sandbox, even if SLACK_CMD auth list already shows other teams.
• The developer asks to log in, switch teams, or re-authenticate.

SLACK_CMD auth list showing other teams is not a reason to skip login — those are different teams. Ask the developer which team they want, then run the flow.

Inspect existing auth (optional)

SLACK_CMD auth list

Use this to show the developer which teams are already authenticated, or to confirm a successful login. Do not treat a non-empty list as "auth complete" when the developer asked to log in to a new team.

Run the seamless login flow

The agent drives this end-to-end — no separate terminal window, no browser confirmation.

SLACK_CMD login --no-prompt makes the CLI emit a single-use ticket and exit immediately instead of waiting on stdin. Slack itself renders the challenge code inside a workspace modal when the developer sends the /slackauthticket slash command — there is no browser step. The agent submits the challenge back to the CLI to complete login.

1. Start login and capture the ticket

SLACK_CMD login --no-prompt

The CLI prints a /slackauthticket slash command and exits. Capture the ticket — you will need it in step 4. Sample output:

📋 Run the following slash command from any Slack channel in the workspace
   you'd like to authenticate

   /slackauthticket eyJ0eXAiOiJKV1QiLCJh…

? Slack will then show you a challenge code. Submit it via:
   slack login --ticket  --challenge 

2. Hand the slash command to the developer

Show the full /slackauthticket … line and ask the developer to paste it into the message box of the Slack workspace they want to authenticate, then send it. Slack responds with a modal containing a short challenge code (e.g. JDt1IK7X).

3. Collect the challenge code

Use AskUserQuestion to ask the developer for the challenge code shown in the Slack modal. Wait for their answer — do not guess or default.

4. Complete login

SLACK_CMD login --ticket  --challenge 

On success the CLI returns the team name and ID. Verify with SLACK_CMD auth list and report the team back to the developer.

Troubleshooting: tickets are single-use and time-limited. If step 4 fails with an invalid/expired ticket or wrong challenge, restart from step 1 with a fresh SLACK_CMD login --no-prompt — do not retry the same ticket.

Use --team on individual commands to target a specific workspace without switching globally.

Red flags — STOP

If you catch yourself thinking any of these, you are about to regress to the old broken flow:

| Rationalization | Reality | |---|---| | "auth list already shows teams, so login isn't needed." | Auth is per-team. The developer asked for a new team — drive the flow. | | "slack login needs browser confirmation, so I can't drive it." | False with --no-prompt. The challenge code appears in Slack's modal, not a browser. The agent runs both slack login invocations itself. | | "I should tell the developer to run slack login in a separate terminal." | Never. Step 5 is the agent's job from start to finish. |

All of these mean: run SLACK_CMD login --no-prompt yourself and follow the four numbered steps above.

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Step 6: Running an App Locally (slack run)

Run SLACK_CMD run --help for all available flags.

Resolve the app or team target

Run SLACK_CMD app list from the project directory to check for installed apps:

• If an app exists: Use --app= in the run command.
• If no apps are listed: Use --team= instead (get the team ID from SLACK_CMD auth list).

Start the dev server in the background

Run this command as a background process so the developer can continue working:

If an app ID was found:

cd  && SLACK_CMD run --org-workspace-grant=all --app=

If no apps — use the team ID:

cd  && SLACK_CMD run --org-workspace-grant=all --team=

Tell the developer the app is running in the background. They can ask:

• "What's the status of the dev server?" — to check on it
• "Show me the output from slack run" — to see activity logs
• "Stop the dev server" — to terminate the process

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Step 7: Managing the Manifest

Run SLACK_CMD manifest --help for subcommands (validate, info) and the --source local|remote flag.

Use SLACK_CMD manifest validate before deploying or when something seems wrong with the app configuration.

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Step 8: Other Commands

For any other command group (e.g., trigger, datastore, env, collaborator, external-auth, deploy), run SLACK_CMD --help to discover subcommands and flags. Run SLACK_CMD help to see all available command groups.

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Notes

• SLACK_CMD is a placeholder — always substitute the actual command name resolved in Step 1.
• Always run --help before constructing a command you have not used in the current session.
• Interactive commands (e.g., slack trigger create without --trigger-def) cannot be run in the background. Tell the developer to run these in a new terminal window. slack login is not in this category — drive it inline using the --no-prompt / --ticket / --challenge flow in Step 5.
• slack run runs locally for development. slack deploy deploys to Slack's hosted infrastructure. These are different operations — do not confuse them.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: slackapi
• Source: slackapi/slack-mcp-plugin
• License: MIT

Install and usage instructions live in the source repository linked above.