Set up the Slack MCP server

Connect Slack to C1 through the Slack API or Slack’s own hosted MCP server, then register the server and govern its tools.

Activation required. AI access management must be enabled for your tenant before you can use it. To get started, contact the C1 support team for a walkthrough.

C1 can govern Slack access two ways. Both let your AI clients read from and act on Slack through governed MCP tools, but they come from different places and appear as two separate entries in your MCP server catalog:

• Slack MCP — listed as plain Slack in your catalog. C1 registers Slack’s own hosted MCP server (mcp.slack.com) as a downstream server C1 governs. Authentication uses Slack’s dedicated user-token OAuth flow: an admin registers a Slack app and provides its client ID and secret to C1 (there’s no dynamic client registration), then each user authorizes individually. A static Slack user token is also supported as a bearer fallback. Tool calls run with the connected user’s User Token Scopes — never a bot identity.
• Slack API — C1 hosts its own MCP server that translates the Slack API into tools. You authorize with per-user OAuth using a Slack app’s client ID and secret, and scope access with the User Token Scopes you configure.

	Slack MCP	Slack API
Who hosts the MCP server	Slack	C1
Authentication	Slack’s user-token OAuth flow via a Slack app you register (client ID/secret; no dynamic client registration) — or a static user token as a bearer fallback	Per-user OAuth via a Slack app’s client ID/secret
Access scoping	The User Token Scopes you request on the Slack app	The User Token Scopes you configure
Tool surface	Slack’s own tool set exposed by its hosted MCP server	Channels, messages, users, files, and search, mapped to Slack API endpoints
Setup effort	Create a Slack app, turn on Enable MCP, configure the user-token OAuth flow (or a static token), then register in C1	Create a Slack app, configure user token scopes, then register in C1

Use the native Slack MCP option (listed as plain Slack in your catalog) if you want Slack’s own hosted tool set and can register a Slack app for its user-token OAuth flow (or a static token). Use Slack API if you’d rather use C1’s own Slack integration with the scopes-based setup you’re already familiar with.

Slack MCP

C1 registers as a client of Slack’s own hosted MCP server (Slack MCP server) rather than translating the Slack API itself. Your users’ AI clients still only ever see C1-governed MCP tools, but C1 proxies each tool call straight through to mcp.slack.com under the connected user’s authorized session (or a configured static token), then returns the result. The tools available are exactly the ones Slack’s own MCP server exposes — C1 doesn’t reshape or add to them.

Before you begin

• AI access management must be enabled for your tenant. See Enable AI access management.
• Permission to create and configure a Slack app. Unlike some MCP servers, Slack’s hosted MCP server doesn’t support dynamic client registration, so you register an app and provide its client ID and secret to C1 before anyone can authorize.
• Only a directory-published or internal Slack app can use the hosted MCP server — see Step 3 below.

In your MCP server catalog, this option is listed as Slack — distinct from the Slack API entry, which connects through C1’s own MCP server. If you don’t see either, contact the C1 support team to enable it for your tenant.

Create a Slack app for MCP

Before configuring authentication, register a Slack app and turn on its MCP support. This step comes before any OAuth configuration — Slack’s hosted MCP server rejects an app that hasn’t enabled it.

1. Sign in at api.slack.com/apps and select Create New App > From scratch. Enter an app name such as C1, pick a workspace to develop in, then select Create App.

2. In the app settings sidebar, open Agents & AI Apps. Under Model Context Protocol, turn on the Enable MCP toggle. Without this, Slack’s hosted MCP server rejects the app.

3. Make the app eligible to use the MCP server: either submit it to the Slack Marketplace (directory-published), or have a workspace admin install it as an internal app. Keep the app ID fixed once you’ve registered it in C1, since C1’s connection pins to it.

Slack MCP scopes

Slack’s hosted MCP server authenticates with a Slack user token (xoxp-), never a bot token, so every scope below is a User Token Scope — add them on the app’s OAuth & Permissions page and leave Bot Token Scopes empty.

Start with the read scopes for browsing channels, messages, users, canvases, files, and search:

search:read.public, search:read.private, search:read.mpim, search:read.im, search:read.files, search:read.users, channels:read, channels:history, groups:read, groups:history, mpim:read, mpim:history, im:history, canvases:read, users:read, users:read.email, reactions:read, emoji:read, files:read

Add the write scopes only where a tool needs them:

chat:write, canvases:write, reactions:write, channels:write, groups:write, im:write, mpim:write

Scope changes take effect the next time a user connects (or the next call using a static token). If you add a scope after users have already connected, each user must reconnect their Slack account — or you must reissue the static token — to grant it.

Option 1: Set up the user-token OAuth flow (recommended)

With per-user OAuth, each person authorizes individually and tool calls run under that user’s own Slack identity. Because the MCP server issues user tokens rather than bot tokens, C1 uses Slack’s dedicated user-token OAuth endpoints — authorizing at slack.com/oauth/v2_user/authorize and exchanging the code at slack.com/api/oauth.v2.user.access — rather than Slack’s classic bot-token authorize and token pair. There’s no dynamic client registration for this flow: you register the Slack app from the previous step, then provide its client ID and secret to C1.

1. In the app settings, open OAuth & Permissions. Under Redirect URLs, select Add New Redirect URL and enter exactly:

   https://accounts.conductor.one/auth/callback
   

   Select Add, then Save URLs.

2. Still on OAuth & Permissions, scroll to Scopes and add the User Token Scopes the tools need — see Slack MCP scopes above.

3. In the left sidebar, open Basic Information. Under App Credentials, copy the Client ID, then reveal and copy the Client Secret.

4. Follow Register an MCP server and select Slack from the catalog.

5. When you configure authentication, choose OAuth2 — per-user passthrough and enter your app’s client ID and client secret, plus the scopes you configured.

6. Save your changes. The first time a user calls a Slack tool from their AI client, they’re redirected to Slack to authorize (if they aren’t already), then returned to C1.

Option 2: Use a static user token (Bearer)

Instead of per-user OAuth, you can connect with a single pre-issued Slack user token. Every tool call then runs as that one token’s identity rather than each individual user’s.

1. In the Slack app’s OAuth & Permissions page, add the same User Token Scopes as in Slack MCP scopes above.

2. Install the app to the workspace, then copy the User OAuth Token (xoxp-…) from that page.

3. Follow Register an MCP server and select Slack from the catalog.

4. When you configure authentication, choose Bearer token and paste the user token.

5. Save your changes. C1 sends the token as Authorization: Bearer <token> on every call to Slack’s MCP server.

The token must carry every scope the tools use; if it’s missing a scope, the corresponding tool call fails. Rotate the token in Slack if it’s ever exposed.

What access is granted

Tool calls run with whichever User Token Scopes you granted — either the connected user’s own scopes (per-user OAuth) or the static token’s scopes (bearer). This is narrower than a blanket grant of everything the user or token holder can do in Slack: a tool call only succeeds if the relevant scope was requested and approved.

How Slack MCP credentials are shared

How Slack sees your users’ activity depends on the method you chose:

• Per-user OAuth (recommended). Each user authorizes with their own Slack account, so tool calls run under that user’s Slack user-token identity, scoped to the User Token Scopes you configured. Slack attributes each action to the individual user.
• Static user token (Bearer). Every user’s tool calls use the one token you provided, so Slack sees a single shared identity. C1 still attributes each call to the individual user in the AI tool usage audit log.

For how shared and per-user credentials work across MCP servers, see Configure authentication.

Discover and govern tools

After you register the server, C1 runs tool discovery against Slack’s MCP server. Discovered tools appear on the server’s Tools tab and are exactly the ones Slack’s own MCP server exposes.

Each tool starts as either Pending review or automatically Approved, depending on the option chosen when the server was set up or your tenant’s default tool settings in AI > MCP > Settings. See Require tool approval and Default tool classification.

Before anyone can call a Slack tool, it must be approved, added to a toolset, and bound to an access profile. Continue to Govern tools and toolsets to set this up.

Tool discovery runs even if authentication isn’t complete yet, so seeing discovered tools doesn’t confirm a user has authorized (or that a static token is valid). You confirm access when an approved user successfully calls a Slack tool from their AI client.

Manage access to Slack MCP

• Rotate the client secret on the app’s Basic Information page under App Credentials, then update the secret on the server’s authentication settings in C1.
• Rotate a static user token by reinstalling the app in Slack to regenerate the User OAuth Token, then update it in C1.
• Revoke access by uninstalling the Slack app from the workspace on OAuth & Permissions, or by turning off the app’s Enable MCP toggle.
• Adjust access by editing the app’s User Token Scopes on the OAuth & Permissions page in Slack.

Slack API

The Slack MCP server lets you govern access to Slack — channels, messages, users, files, and search — as tools your AI clients can call through C1.

Slack uses per-user OAuth, which is recommended: each person authorizes with their own Slack account, so every tool call runs under that user’s identity and permissions.

How C1 connects to Slack

C1 hosts the Slack MCP server, so your users’ AI clients only ever see MCP tools — they never call Slack directly. When an AI client calls one of these tools, C1 makes the matching request to the Slack API using the credentials you configure here, then returns the result to the AI client.

The credentials you set up below are what C1 uses to call Slack on your users’ behalf.

Before you begin

• AI access management must be enabled for your tenant. See Enable AI access management.
• Permission to create and configure a Slack app. See Slack’s guide to installing apps with OAuth.

In your MCP server catalog, this option is listed as Slack API — distinct from the Slack entry, which connects to Slack’s own hosted MCP server. If you don’t see either, contact the C1 support team to enable it for your tenant.

Create a Slack app

With per-user OAuth, you register one Slack app and each user authorizes individually. This keeps every action attributable to the user who took it, with only the access that user already has in Slack.

1. Sign in to the Slack apps dashboard and select Create New App > From scratch. Enter an app name such as C1, pick a workspace to develop in, then select Create App. For detail on the OAuth flow, see Slack’s guide to installing apps with OAuth.

2. In the app’s left sidebar, open OAuth & Permissions. Under Redirect URLs, select Add New Redirect URL and enter exactly:

   https://accounts.conductor.one/auth/callback
   

   Select Add, then Save URLs.

3. Still on OAuth & Permissions, scroll to Scopes and add the User Token Scopes from Slack scopes below — the default read scopes for browsing, plus any optional scopes for write or admin tools. User token scopes let the app act as each authorizing user.

4. In the left sidebar, open Basic Information. Under App Credentials, copy the Client ID, then reveal and copy the Client Secret.

Slack scopes

C1 uses user token scopes only — every tool call acts as the authorizing user, not as a bot. Add all of the scopes below under User Token Scopes on Slack’s OAuth & Permissions page; leave Bot Token Scopes empty.

C1 requests the default read scopes automatically. The default is read-only; to enable write or admin tools, an admin adds the optional scopes below manually — under User Token Scopes in Slack, and in C1’s scopes field when configuring authentication. Grant only what you need.

Default scopes browse channels and messages (public channels, private channels, direct messages, and group direct messages), users, user groups, files, pins, and message search:

channels:read, channels:history, groups:read, groups:history, im:read, im:history, mpim:read, mpim:history, users:read, users:read.email, usergroups:read, files:read, pins:read, search:read

Optional scopes enable the write and admin tools — add only what you need:

Scope(s)	Enables
chat:write	Send, update, schedule, and delete messages
reactions:read	View emoji reactions
reminders:read, stars:read	View reminders and saved items
remote_files:read, remote_files:share	View and share remote files
users.profile:write, users:write	Edit the authorized user’s profile, photo, and presence
channels:write, groups:write, im:write, mpim:write (and the .invites / .topic variants)	Create and manage channels and direct messages, invite people, and set topics
dnd:read, calls:read	View Do Not Disturb settings and calls
admin.conversations:read / :write, admin.teams:read / :write, admin.invites:read, admin.users:read / :write	Manage channels, workspace settings, invites, and users org-wide (Enterprise Grid only; requires an org-level admin install)

Scope changes take effect the next time a user connects. If you add an optional scope after users have already connected, each user must reconnect their Slack account to grant it.

How Slack credentials are shared

With per-user OAuth, each user authorizes with their own Slack account, so tool calls run under that user’s Slack identity and inherit only the access they already have. Slack attributes each action to the individual user.

For how shared and per-user credentials work across MCP servers, see Configure authentication.

Register the Slack MCP server in C1

Register the server in C1 and connect it to the Slack app you created.

1. Follow Register an MCP server and select Slack API from the catalog.

2. When you configure authentication, choose per-user OAuth and enter your app’s client ID and client secret, plus the scopes you configured (see Slack scopes).

3. Save your changes. The first time a user calls a Slack tool from their AI client, they’re prompted to connect their Slack account.

Discover and govern tools

After you register the server, C1 runs tool discovery against Slack. Discovered tools appear on the server’s Tools tab.

Each tool starts as either Pending review or automatically Approved, depending on the option chosen when the server was set up or your tenant’s default tool settings in AI > MCP > Settings. See Require tool approval and Default tool classification.

Before anyone can call a Slack tool, it must be approved, added to a toolset, and bound to an access profile. Continue to Govern tools and toolsets to set this up.

Tool discovery runs even if your credentials are incorrect, so seeing discovered tools doesn’t confirm that authentication is working. You confirm your Slack credentials when an approved user successfully calls a Slack tool from their AI client.

Manage your Slack credentials

• Rotate the client secret on the app’s Basic Information page under App Credentials, then update the secret on the server’s authentication settings in C1.
• Adjust access by editing the app’s User Token Scopes on the OAuth & Permissions page in Slack.