Giving Claude access to Slack — every option

TL;DR

• Easiest route for Claude Code: Slack's official MCP server, if your workspace admin allows it.
• If the MCP is blocked, create your own Slack app with a read-only user token (xoxp-) and let Claude call the Web API.
• Claude in Slack (@Claude) works inside Slack only. It doesn't give Claude Code in your terminal or IDE any Slack access.
• The Slack CLI and webhook or bot tokens you may already have can't read message history.
• Posting needs chat:write: a user token posts as you, a bot token posts as the app, and a webhook posts to one fixed channel.
• Start with the MCP. If it's blocked, request a private read-only app; don't scrape the desktop app's session token.

Contents

1. The options at a glance
2. How to choose
3. Option A — Slack's official MCP server
4. Option B — Your own Slack app with a user token
5. Option C — Your own Slack app with a bot token
6. Option D — A community MCP server with your token
7. Option E — Claude in Slack (@Claude)
8. Writing messages
9. Things that look like options but aren't
10. Scopes reference
11. Security notes

---

The options at a glance

Option	Where Claude runs	Reads channels	Reads DMs	Search	Posts messages	Admin approval	Effort
A. Slack MCP server	Claude Code, other MCP clients	Yes	Yes (yours)	Yes	Yes, as you	Usually	Low
B. Own app + user token	Claude Code via a script or skill	Yes	Yes (yours)	Yes	With chat:write, as you	Usually	Medium
C. Own app + bot token	Claude Code via a script or skill	Only channels the bot is invited to	No	No	With chat:write, as the app	Usually	Medium
D. Community MCP + token	Claude Code	Same as the token you give it	Same	Same	If the token and server allow it	Same as B or C	Medium
E. Claude in Slack	Inside Slack	Thread it's tagged in, plus public search	Only its own DM with you	Public channels	Replies in the thread, as @Claude	Yes (Team/Enterprise plan)	Low
F. Incoming webhook	Anywhere that can send an HTTP POST	No	No	No	Yes, to one fixed channel	Usually	Very low

Every token-based option sees at most what the token's owner can see. A user token acts as you; a bot token acts as the bot.

How to choose

Your situation	Pick
Your admin allows Slack's MCP server	A
The MCP is blocked, but your admin approves custom apps	B
You only need a few shared channels, not DMs or search	C
You want MCP tools instead of shell calls, and you trust the project	D, using the token from B or C
You want to ask Claude about a thread while you're in Slack	E
Claude should post to Slack as you (replies, updates)	A, or B with chat:write
Claude or a script should post as an app (alerts, summaries, reports)	C with chat:write
You only need notifications posted to one channel	F
Nothing is approved	Paste the thread text or export into Claude by hand

---

Option A — Slack's official MCP server

Slack hosts an MCP server at https://mcp.slack.com/mcp. Claude Code connects to it over HTTP and logs in with OAuth as you.

Setup in Claude Code

1. Check Slack's MCP documentation for the client ID and callback port to use with Claude Code. Slack's server needs a client it has registered in advance, so a plain URL isn't enough.

2. Add the server:

   claude mcp add --transport http --client-id <client-id> --callback-port <port> \
     slack https://mcp.slack.com/mcp
   

3. In an interactive Claude Code session, run /mcp, pick slack, and finish the browser login.

4. Ask something that needs Slack, for example "summarise yesterday in #dev".

Gotchas

• /mcp showing Needs authentication means the OAuth step hasn't been done. Non-interactive sessions (claude -p, cron) can't complete it.
• Workspace admins can block the MCP app. When they have, the login fails and nothing on your side fixes it. Move on to B.
• If claude.ai offers a Slack connector, it probably goes through Slack's MCP too, so the same admin block would apply.
• The server includes tools that send messages as you, not just read ones. To make Claude ask before posting, leave those tools out of the allow list in settings.json, so each send prompts you for approval.

Option B — Your own Slack app with a user token

This is the fallback that works when the MCP is blocked but your admin approves custom apps. You create a private Slack app that requests only user read permissions, install it, and give Claude the resulting xoxp- token.

1. Create the app from a manifest

Go to https://api.slack.com/apps, click Create New App, choose From a manifest, pick your workspace, and paste:

display_information:
  name: Claude Reader
  description: Read-only access to my own Slack for Claude Code
oauth_config:
  scopes:
    user:
      - channels:read
      - channels:history
      - groups:read
      - groups:history
      - im:read
      - im:history
      - mpim:read
      - mpim:history
      - users:read
      - search:read
settings:
  token_rotation_enabled: false

Drop any permissions you don't need. For example, remove im:* and mpim:* if Claude shouldn't read DMs. A shorter list is also easier to get approved.

To let Claude post too, add write permissions under the same user: list:

      - chat:write        # post, edit and delete your own messages
      - reactions:write   # add emoji reactions
      - im:write          # open a DM with someone before posting to it
      - files:write       # upload files

These permissions let Claude post as you. Consider a separate app (or a bot token, option C) for writing, so a read-only token stays read-only. See Writing messages.

2. Install it

1. Open OAuth & Permissions and click Install to Workspace.
2. If the button says Request to Install, your admin has to approve it. Explain in one line why you need it and that it has no write permissions.
3. Once installed, copy the User OAuth Token (xoxp-…) from the same page.

Keep token rotation off. With rotation on, the token expires every 12 hours and you'd need a refresh flow.

3. Store the token outside your shell history

OS	Store	Read
macOS	security add-generic-password -a "$USER" -s SLACK_READ_TOKEN -w (prompts for the value)	security find-generic-password -a "$USER" -s SLACK_READ_TOKEN -w
Windows	Credential Manager (cmdkey or the CredentialManager PowerShell module)	The same module's Get-StoredCredential
Linux	secret-tool store --label=slack service SLACK_READ_TOKEN	secret-tool lookup service SLACK_READ_TOKEN

Don't paste the token into a prompt, a committed file or a shared doc.

4. Test it

T=$(security find-generic-password -a "$USER" -s SLACK_READ_TOKEN -w)   # macOS
curl -s -H "Authorization: Bearer $T" https://slack.com/api/auth.test
curl -s -H "Authorization: Bearer $T" "https://slack.com/api/search.messages?query=deploy&count=5"

auth.test should return "ok": true with your user name. A missing_scope error names the permission you still need to add.

5. Connect it to Claude Code

Pick one, or combine them:

Approach	What it is	Good for
Skill (~/.claude/skills/slack/SKILL.md)	Instructions telling Claude where the token is and which API methods to call	Loads automatically whenever you mention Slack
Wrapper script (e.g. slack.sh history <channel> <n>)	Turns raw JSON into short readable text	Saves context; easy to allow in permissions
Community MCP server	See option D	When you'd rather have tools than shell calls

A minimal skill could look like this:

---
name: slack
description: Read Slack channels, threads, DMs and search results with my read-only user token. Use when I ask about anything in Slack.
---

Read the token with `security find-generic-password -a "$USER" -s SLACK_READ_TOKEN -w`
and send it as `Authorization: Bearer`. Never print it.

| Need | Method |
|---|---|
| Find a channel ID | `conversations.list` (types=public_channel,private_channel) |
| Recent messages | `conversations.history?channel=<id>&limit=<n>` |
| A thread | `conversations.replies?channel=<id>&ts=<thread_ts>` |
| Search | `search.messages?query=<q>` |
| A user's name | `users.info?user=<id>` |

Read-only: never call chat.*, reactions.* or any other write method.

For a skill that can also post, swap the last line for a confirmation rule, e.g. "Before calling chat.postMessage, show me the channel and the exact text and wait for my OK."

The Web API methods you'll use

Method	Returns
conversations.list / users.conversations	Channels (all of them, or only the ones you're in)
conversations.history	A channel's messages, newest first, paged with cursor
conversations.replies	Every message in one thread
search.messages	Search results, using the same syntax as the Slack search box (in:#dev from:@x after:2026-01-01)
users.info / users.list	Turns user IDs (U…) into names

Rate limits: in 2025 Slack tightened the limits on conversations.history and conversations.replies for apps outside its Marketplace. Its announcement exempted apps a workspace builds for its own use. If reads seem throttled, check the current limits page.

Option C — Your own Slack app with a bot token

The setup is the same as B, but you add bot permissions (channels:history, channels:read, users:read, …) and use the Bot User OAuth Token (xoxb-…).

• The bot only sees channels it's been invited to (/invite @YourApp).
• It can't see your DMs.
• It can't use search.messages, because search is only available to user tokens.

Pick C when you want Claude's access limited to a few shared channels and not tied to your own account.

C is also the usual choice for posting. Messages show the app's name and icon, so readers can see they came from automation, not from a person. Useful bot write permissions:

Scope	Lets the bot
chat:write	Post in channels it has been invited to
chat:write.public	Post in any public channel without being invited
chat:write.customize	Change the name and icon shown on each message

Option D — A community MCP server with your token

Open-source Slack MCP servers, such as korotovsky/slack-mcp-server, take the token from B or C and expose it to Claude Code as MCP tools.

• Pros: proper tools (channels_list, conversations_history, search), so you don't maintain your own script.
• Cons: third-party code holds your token. Read the source, pin a version, and give it the read-only token from B, never one with write permissions.
• Some of these servers also accept browser session tokens. See the warning under Things that look like options but aren't.
• Message-posting tools are often turned off by default and switched on with a setting or environment variable. Check the project's README, and only switch them on if the token has chat:write.

Option E — Claude in Slack (@Claude)

Anthropic's Slack app, also called Claude Tag, puts Claude inside Slack. It needs a Claude Team or Enterprise plan, and a workspace admin installs it and links it to your Claude organisation.

Where	How	What Claude sees
A channel thread	Tag @Claude with a request	That thread, recent channel history, public-channel search
A private channel	Run /invite @Claude first	That channel
Its DM	Message the app	Your own Claude account, if you linked it on the app's Home tab
Channels with guests	—	Workspace search is turned off

It runs separately from Slack's MCP server, so a block on the MCP doesn't affect it. It doesn't give Claude Code in your terminal or IDE any Slack access.

---

Writing messages

Which identity posts

Route	Message appears as	Can post to
User token with chat:write (A, B)	You	Anywhere you can post, including DMs
Bot token with chat:write (C)	The app	Channels it's invited to, or any public channel with chat:write.public
Incoming webhook (F)	The app	One channel, chosen when the webhook was created
Claude in Slack (E)	@Claude	The thread it was tagged in

Option F — Incoming webhook

This is the simplest way to post, and it can't read anything. In your app's settings, turn on Incoming Webhooks, click Add New Webhook to Workspace, and pick a channel. You get a URL like https://hooks.slack.com/services/T…/B…/….

curl -s -X POST -H 'Content-Type: application/json' \
  --data '{"text":"Deploy finished :white_check_mark:"}' "$SLACK_WEBHOOK_URL"

• The URL is the secret. Anyone who has it can post to that channel, so store it like a token.
• A webhook can't post to another channel, read messages, reply in a thread it didn't start, or edit or delete messages.

Web API methods for writing

Method	Does	Scope
chat.postMessage	Post a message. Pass thread_ts to reply in a thread	chat:write
chat.update / chat.delete	Edit or delete a message the same token posted	chat:write
chat.scheduleMessage	Post at a set time (post_at, a Unix timestamp)	chat:write
chat.postEphemeral	Show a message to one person in a channel, visible only to them	chat:write
conversations.open	Get the DM channel ID for a user before posting to them	im:write
reactions.add	Add an emoji reaction	reactions:write
files.getUploadURLExternal + files.completeUploadExternal	Upload a file (the older files.upload is retired)	files:write

# Reply in a thread
curl -s -X POST https://slack.com/api/chat.postMessage \
  -H "Authorization: Bearer $T" -H 'Content-Type: application/json; charset=utf-8' \
  --data '{"channel":"C0123456789","thread_ts":"1735689600.123456","text":"Fixed in the latest deploy."}'

• channel takes an ID (C…, G…, D…). Look IDs up with conversations.list, or open a channel's details in Slack and copy the ID from the bottom.
• Slack returns HTTP 200 even when a call fails, so check "ok" in the response. Common errors are not_in_channel (invite the bot), channel_not_found and missing_scope.
• Keep posts to about one message per second per channel. Slack rate-limits bursts beyond that.

Formatting

Slack uses mrkdwn, which isn't standard Markdown. Claude writes standard Markdown by default, so say so in your skill or prompt.

Want	mrkdwn
Bold / italic / strike	*bold* _italic_ ~strike~
Link	<https://example.com|label> (one pipe, between URL and label)
Mention a person / channel	<@U0123456789> <#C0123456789>
Mention a group	<!here> <!channel> <!subteam^S0123456789>
Code	`inline` and ``` blocks

There are no headings or tables in mrkdwn. For richer layouts, send blocks (Block Kit) and keep a plain text fallback for notifications.

Keeping Claude's posting safe

• Ask before every send. Don't add the post command or the MCP's send tools to the Claude Code allow list, so each one asks for your approval. Your skill should also tell Claude to show the channel and text first.
• Draft, then send. Have Claude write the message into the chat, then send it yourself or say "send it". Many people only need drafting help.
• Separate the tokens. Use a read-only user token for research and a bot token for posting. A mistake in a read step then can't post as you.
• Never let unattended runs post as you. Cron jobs, claude -p and CI should use a bot token or a webhook.
• Watch the mentions. <!channel> and <!here> notify everyone in the channel. Tell Claude never to use them unless you ask.

Things that look like options but aren't

Thing	Why it doesn't work
Slack CLI (slack login)	It's for building Slack apps. Its login token has a fixed set of permissions (list channels and users, manage apps) and can't be given *:history, so conversations.history fails with missing_scope
Incoming webhook or "post-only" bot token (as a way to read)	Fine for posting (option F), but they can't read. Check with auth.test and look at the x-oauth-scopes response header
The desktop app's session token (xoxc- plus the d cookie)	Technically it can read everything, but it gets around your admin's app controls, probably breaks workspace policy, and stops working when you log out. Don't use it as a workaround when your admin has said no
Workspace data export	Admin-only, a one-off snapshot, and usually public channels only

Scopes reference

Scope	Lets you	Token types
channels:read / channels:history	List and read public channels	User, bot
groups:read / groups:history	List and read private channels you're in	User, bot
im:read / im:history	List and read direct messages	User (yours); bot (its own DMs only)
mpim:read / mpim:history	List and read group DMs	User, bot
users:read	Turn user IDs into names	User, bot
search:read	search.messages	User only
chat:write	Post, edit and delete messages	User (as you), bot (as the app)
chat:write.public	Post to public channels without being invited	Bot only
chat:write.customize	Change the name and icon on each message	Bot only
im:write / mpim:write	Open DMs and group DMs to post to	User, bot
reactions:write	Add emoji reactions	User, bot
files:write	Upload files	User, bot
incoming-webhook	Create a webhook URL for one channel	Added when you set up a webhook

To see what a token can do, run curl -sD - -o /dev/null -H "Authorization: Bearer $T" https://slack.com/api/auth.test | grep -i x-oauth-scopes.

Security notes

• Prefer read-only permissions. A token with chat:write lets Claude post as you. Add write permissions only when you need them, ideally on a separate app or a bot token.
• Treat webhook URLs as secrets. Anyone who has one can post to its channel.
• Keep tokens in the OS credential store, never in prompts, repos, .env files that get committed, or docs.
• A user token sees your DMs. If Claude's output ends up somewhere shared, leave the im:* permissions out.
• To revoke access, go to api.slack.com/apps, open your app, and click Revoke tokens, or uninstall it from the workspace.
• If a token leaks, revoke it straight away and reinstall the app to get a new one.