Claude Code in Slack — Complete Setup + 5 Free AI Automations (2026)

Claude Code in Slack — Free AI Automations on Your Existing Plan

I just had Claude review a pull request, write technical documentation to my GitHub repo, generate my standup, and analyze a production error — all without leaving Slack. No paid Slack AI tier, no custom code, no webhooks.

This guide walks you through the complete setup of Anthropic's official Claude in Slack app, plus five real automations you can run for free with your existing Claude Pro plan.

What You'll Build — 5 Automations

Standup Summary — Claude reads yesterday's #standup channel and gives you a 3-bullet brief.
PR Review — paste a GitHub PR link and Claude reviews it back in the thread (and can fix bugs + open a PR).
Thread → Docs — turn any technical Slack thread into a Markdown doc committed to GitHub.
Error Analyzer — paste any error log and Claude finds the bug AND opens a fix PR.
Git → Standup — Claude reads YOUR yesterday's commits and posts your standup automatically.

All five run on Anthropic's official Slack app. All five work with your existing Claude Pro plan. No extra cost.

Prerequisite: A Claude Plan That Includes Claude Code

Before anything, verify you're on a plan that includes Claude Code: Pro, Max, Team, or Enterprise. Free won't work.

If you're not sure, go to claude.ai → Settings → Billing.

Step 1: Install Claude in Slack from the Marketplace

Open Anthropic's official Claude app on Slack Marketplace. Click Add to Slack, pick the workspace you want to use, and click Allow to authorize.

It's free, official, and takes two clicks.

Step 2: Connect Your Anthropic Account in Slack

Open Slack. In the left sidebar, scroll down to find the Claude app. Click it, then click Connect to Account.

This opens a browser tab. Click Authorize — you'll see a success message. Back in Slack, the Claude app shows several options now.

Each user does this once. Your individual plan handles the AI quota — there's no team-wide billing.

Step 3: Set Routing Mode to "Code + Chat"

Inside the Claude app home in Slack, find the routing mode setting and select Code + Chat (not Code only).

This is critical. Code-only mode breaks the channel-summary demos. Code + Chat lets Claude handle both code work AND chat-style summarization.

Step 4: Connect Your GitHub Repo at claude.ai/code

Open claude.ai/code. If your GitHub account isn't connected yet, you'll see a button to connect it — follow the prompts to install the Claude GitHub App on the specific repo you want Claude to read and write to.

Once connected, search for your repo name in the connected repositories search. If it appears, it's accessible by Claude Code in Slack.

Without this step, every demo fails. Claude in Slack only works on repos visible at claude.ai/code.

Step 5: Invite @Claude to Your Channels

Go back to Slack. For each channel you want Claude to work in, type:

/invite @Claude

Hit Enter. You'll see a confirmation message. Repeat for every channel — for this tutorial, that's #bugs, #engineering, #general, #random, and #standup.

By design, Claude does not respond in DMs. It only works in channels you've invited it to.

Step 6: Final Sanity Check

In #general (or any channel), type:

@Claude hello

Claude adds a "thinking" emoji and creates a thread. Open the thread — you'll see a general response. If you ask about a specific repo, Claude routes the message to Code mode automatically. You can also force a specific repo by mentioning the repo name in your prompt.

Once you get a reply, setup is complete. Now to the automations.

Demo 1: Standup Summary

Open #standup. Type:

@Claude summarize the last 24 hours of this channel into 3 bullets — what each person worked on, blockers, and shipped items

Claude routes to Chat mode (this is summarization, not code). A few seconds later, you get a clean 3-bullet brief organized into Worked on / Blockers / Shipped.

Claude ingests the full channel history — multiple people's messages, replies, threads — and produces a useful daily summary in seconds. Saves 5 minutes every morning.

Demo 2: PR Reviewer (With Auto-Fix Bonus)

Open #engineering. Paste:

@Claude review github.com/your-org/your-repo/pull/1 — focus on bugs and missing tests

Claude spins up a Code session in the cloud. You'll see a View Session button — click it to watch live as Claude clones the repo, reads the diff, and forms its review.

The review posts back in the thread. In my test, Claude found the bug I'd planted: missing error handling on JSON parse. It also identified the missing tests.

Bonus: Tell Claude to Fix It

Reply in the thread (always tag @Claude):

@Claude yes please fix it

Claude spins up a new session, fixes the bugs, adds the missing tests, creates a new branch, commits, and opens a PR — all from a Slack message.

Heads-up: if you get a permissions error, the Claude GitHub App might not have write access to that specific repo. Visit github.com/apps/claude, click Configure, pick the repo or organization, and authorize. Then re-run the prompt.

Demo 3: Thread → Docs to GitHub

Open a long technical thread in #engineering. Reply in the thread:

@Claude write this thread up to /docs/stripe-webhook-retries.md in repo your-org/your-repo. When done, post the branch and PR link here.

Claude opens a session, switches to your repo, reads the entire thread context, writes a clean Markdown doc, creates a branch, commits, and opens a PR.

The PR even links back to the original Slack thread, so future reviewers can trace the conversation that drove the doc. Click into the new file — it's properly structured Markdown documentation, not a raw transcript.

Demo 4: Error Analyzer (Auto-Fix PR)

Open #bugs. Paste a production error:

@Claude analyze this error and suggest a fix:

Error: Stripe webhook returned 503 Service Unavailable
  at processWebhook (src/webhooks/stripe.js:42)
  at handleRequest (src/router.js:88)
Stack trace shows retry attempted 5 times, all failed.
Repo: your-org/your-repo

Claude opens the file, finds the actual problematic line, identifies the root cause, and edits the relevant files (e.g. database connection pool size + retry logic).

It commits to a new branch, pushes, and opens a PR with the fix already implemented. Click Create PR — the title and description are pre-filled. Review, click Merge Pull Request, confirm — done.

From error log to merged code in two clicks.

Demo 5: Standup From Git Commits

Open #standup. Paste:

@Claude generate my standup from yesterday's commits in repo your-org/your-repo. Group as: Shipped / In Progress / Blockers. Post here.

Claude reads your commit history from the last 24 hours, groups them into Shipped / In Progress / Blockers, and posts the standup directly in the channel — in your voice, based on your actual commits.

Saves 10 minutes every single morning. You'll never write a standup by hand again.

Common Gotchas

Issue	Fix
Wrong repo selected	Click "Change Repo" or include `owner/repo` in the prompt
Routed to Chat instead of Code	Click "Retry as Code" or set routing mode to Code only
"I don't have access to that repo"	Install Claude GitHub App at github.com/apps/claude on that specific repo
Rate limit hit	Each @mention spins up a Claude Code session counted against your plan — upgrade to Max if you're heavy-using
"Create PR" button doesn't react	PR was already created — click "View Session" → "View PR" instead
Slack DMs unsupported	By design — Claude only responds in channels. Use `/invite @Claude` first.

Recap + Useful Links

Five Slack automations: standup summary, PR review, thread to docs, error analyzer, git to standup. All running on Anthropic's official Slack app. Totally free with your existing Claude Pro plan.

Claude in Slack (official): slack.com/marketplace
Claude Code on the web: claude.ai/code
Claude GitHub App: github.com/apps/claude