slackapi/slack-mcp-plugin/create-slack-app

Create Slack App

Help the developer create a Slack app or agent using Bolt. If $0 is exactly bolt-js or bolt-python, treat it as the chosen framework and skip asking. Otherwise (including if it's empty or any other value), ignore it and ask the developer which framework they want before continuing.

This skill walks through the full setup: prerequisites, authentication, choosing a workspace to install into, project scaffolding from a template, and running the app locally.

Existing App from App Settings

The developer may already have created and installed the app in App Settings, which hands off with arguments in the developer's message, for example --app A0123456789 --template slack-samples/bolt-js-starter-agent --team T0123456789. The agent setup prompt passes them along, after turning the App Settings template name into a template repo:

When --app is present, follow this skill as an existing app. The app ID, template, and team are already decided, so do not ask about them again. The framework is the template's language: bolt-js for a slack-samples/bolt-js-* repo and bolt-python for slack-samples/bolt-python-*, so do not ask for it either. Each step below says what changes. Check every value against the table before putting it in a command. If a value doesn't match, or --app comes without --template and --team, tell the developer which value is wrong and ask for it rather than guessing.

Step 1: Check Prerequisites

1a. Detect the Slack CLI command

Use the slack-cli skill — Step 1: Detect the Slack CLI — to check whether the public Slack CLI is installed and resolve its command name. The fingerprint check, alias fallback, and install instructions all live there; do not duplicate them here.

Once resolved, use the detected command name for all CLI commands throughout the rest of this skill. We refer to it as SLACK_CMD below — substitute the actual resolved command name everywhere you see SLACK_CMD.

1b. Verify the CLI version

Run SLACK_CMD version and print the version to confirm everything is working before continuing.

1c. Check language runtime

• If `$0` is `bolt-js`: Run node --version to verify Node.js is installed (v18+ required). If not installed, suggest brew install node or point to <https://nodejs.org>.
• If `$0` is `bolt-python`: Run python3 --version to verify Python is installed (3.6+ required). If not installed, suggest brew install python3 or point to <https://python.org>.

Step 2: Authenticate with the Slack CLI

Use the slack-cli skill — Step 5: Authentication (`slack auth`) — to check the developer's auth status and walk them through SLACK_CMD login if they're not already authenticated.

Wait for confirmation that authentication succeeded before proceeding.

Existing app: the CLI must be logged in to the team from --team. Check that SLACK_CMD auth list shows that team ID. If it doesn't, log in to that workspace with the same flow.

Step 3: Choose Where to Install the App

Existing app: skip this step. The app is already installed in the team from --team.

The app needs a Slack workspace to install into. Three targets work and they are not equivalent. Use AskUserQuestion to let the developer pick, presenting them in this order:

Then follow the matching sub-step below. Whichever target they pick, authentication is the same Step 2 flow: the /slackauthticket command works in any workspace the developer belongs to, so there is no sandbox-specific login.

Whichever sub-step you follow, wait for confirmation that a target workspace exists and is authenticated before proceeding.

3a. Developer sandbox (recommended)

List existing sandboxes. Pass --team so the CLI does not stop to ask which authentication to use (get the team ID from SLACK_CMD auth list):

SLACK_CMD sandbox list --team <team_id>

If the developer has no Developer Program account, sandbox list returns nothing useful, because sandboxes belong to the developer program account whose email matches the authenticated user rather than to the workspace. If they say they do have an account, check that the email they are logged in with matches it before sending them to sign up, and log into a workspace under that email if not. Point them at <https://api.slack.com/developer-program/join>, and offer the Free Team path in 3b as a way to start building now rather than waiting on signup.

• If a sandbox exists: Show it and confirm they want to use it.
• If no sandbox exists: Create one. Ask the developer for a name and a password with AskUserQuestion, then run:

``bash SLACK_CMD sandbox create --team <team_id> --name <sandbox-name> --password <password> ``

Important: the password is a credential. Do NOT echo it, restate it, or write it into a summary. Pass it straight to the command, the same rule Step 4c applies to API keys.

Sandboxes can also be created in the browser at <https://api.slack.com/developer-program/sandboxes>.

Once the sandbox exists, have the developer log into it with the Step 2 flow before continuing.

Basic sandboxes. A developer who is not on a paid plan and has not added a payment method gets a basic sandbox. It works for everything this skill builds, with stricter limits: it is archived after 1 month of inactivity, has no Slack Connect, and does not support deploying apps to Slack infrastructure (ROSI). If the developer needs more, they can add a payment method (they are not charged) or join a paid plan, then upgrade the sandbox from <https://api.slack.com/developer-program/sandboxes> without losing their apps or data. Limits are listed at <https://docs.slack.dev/tools/developer-sandboxes#basic>.

3b. Free Team (second choice)

A Free Team is an ordinary Slack workspace on the free plan. The developer creates one at <https://slack.com/get-started>, then logs into it with the Step 2 flow.

What to tell them:

• Everything this skill builds works there. Bolt apps install and run fine on the free plan.
• The workspace is capped at 10 apps. Past that the CLI reports service_limits_exceeded.
• It is a standalone workspace, not an Enterprise Grid org, unlike a developer sandbox. Anything org-level is therefore untestable: org-wide app installs and org-level app grants, the admin.* API methods (which need Business+ or Enterprise Grid), and multi-workspace behaviour generally. If the app targets those, use a sandbox instead.
• Do not invite coworkers into it. A Free Team with real users in it is a production workspace for the purposes of 3c.

3c. Existing production workspace (last resort)

Only when the app genuinely needs real data or real users. Warn the developer before they log in:

• Admin app approval (AAA) is likely to block the install. It is always on for Enterprise Grid organizations and can be switched on in standalone workspaces. When it applies, the install in Step 5 stops and asks whether to request approval, and then the developer waits on an admin.
• To send that request without the prompt, set SLACK_AUTO_REQUEST_AAA=1 in the environment. It is an environment variable, not a CLI flag.
• If approval is denied or slow, fall back to 3a or 3b instead of fighting it.

Step 4: Create the App from a Template

Ask the developer what kind of app they want to build. Present the available templates based on their chosen framework ($0):

bolt-js templates

bolt-python templates

Use AskUserQuestion to let the developer pick a template. Recommend the Starter Template for first-timers or the Starter Agent if they want to build an AI agent.

Existing app: do not ask which template. Use the repo from --template.

4a. Choose an AI provider (agent templates only)

If the developer picks Starter Agent or Support Agent, these templates contain subdirectories for different AI providers. Ask the developer which provider they want to use via AskUserQuestion, offering only the subdirectories for their framework ($0) from the tables below.

The provider list depends on the framework, so the framework must be settled before you ask. If it isn't yet, ask for the framework first and wait for the answer. Do not batch the framework and provider questions into one AskUserQuestion call.

bolt-js subdirectories:

bolt-python subdirectories:

Recommend Claude Agent SDK as the default option.

Existing app: the same rule applies when --template is a Starter Agent or Support Agent repo. If --subdir was given, use it and skip the question.

4b. Name and create the project

Ask what they want to name their project (suggest a default like my-slack-app), then run:

For templates WITHOUT subdirectories (Starter Template, Getting Started, Assistant Template, Examples):

SLACK_CMD create <project-name> -t <template-repo>

For agent templates WITH subdirectories (Starter Agent, Support Agent):

SLACK_CMD create <project-name> -t <template-repo> --subdir <chosen-subdir>

For example: