Let Claude Duet catch a broken change you missed in Slack
An Anthropic engineer used Claude Duet to build Duet itself. It proactively told him a change he made was broken, which he had missed in a flood of Slack messages.
Source
@gabemulley on X · 2026-10-21
Written in our own words. Credit to the original author. Link checked 2026-10-23.
What they did
An Anthropic engineer used Claude Duet to build Duet itself. It proactively told him a change he made was broken, which he had missed in a flood of Slack messages.
Result (as claimed)
He says it fundamentally changed how he uses Claude and AI.
Tools they used
Cost: Pricing depends on the tools you pick; check each official pricing page.
Set it up
Pick a contained repo or task
Start on a branch or side project where mistakes are cheap.
Install and configure
Set up Claude Duet, Claude, Slack. Read what it can run on your machine and limit permissions where possible.
Run it on a real task
Give it a well-scoped issue and let it work. Review the diff like any pull request.
Add guardrails
Keep tests and CI in the loop, and never let an agent push to main or touch production secrets unattended.
Copy the full setup prompt
Paste into your agent and it will walk you through the setup, asking before anything that sends, posts or spends.
You are helping me set up this AI use case end to end in Claude Code. Goal: Let Claude Duet catch a broken change you missed in Slack What the original author did: An Anthropic engineer used Claude Duet to build Duet itself. It proactively told him a change he made was broken, which he had missed in a flood of Slack messages. Reported result (as claimed by the author): He says it fundamentally changed how he uses Claude and AI. Source: https://x.com/gabemulley/status/2112986479290925283 Tools they used: Claude Duet, Claude, Slack Category: Dev & ops Please: 1. Ask me 3 short questions about my situation (accounts I have, budget, what I want the output to look like). 2. Propose a step-by-step plan using these tools or cheaper alternatives, with the time and cost of each step. Use official pricing pages; say "check pricing" if unsure. 3. Then do the setup with me one step at a time, waiting for my OK before anything that sends messages, posts publicly, spends money or deletes data. 4. Finish with a checklist to run it again next time.
You are helping me set up this AI use case end to end in Codex. Goal: Let Claude Duet catch a broken change you missed in Slack What the original author did: An Anthropic engineer used Claude Duet to build Duet itself. It proactively told him a change he made was broken, which he had missed in a flood of Slack messages. Reported result (as claimed by the author): He says it fundamentally changed how he uses Claude and AI. Source: https://x.com/gabemulley/status/2112986479290925283 Tools they used: Claude Duet, Claude, Slack Category: Dev & ops Please: 1. Ask me 3 short questions about my situation (accounts I have, budget, what I want the output to look like). 2. Propose a step-by-step plan using these tools or cheaper alternatives, with the time and cost of each step. Use official pricing pages; say "check pricing" if unsure. 3. Then do the setup with me one step at a time, waiting for my OK before anything that sends messages, posts publicly, spends money or deletes data. 4. Finish with a checklist to run it again next time.
You are helping me set up this AI use case end to end in Grok Bot. Goal: Let Claude Duet catch a broken change you missed in Slack What the original author did: An Anthropic engineer used Claude Duet to build Duet itself. It proactively told him a change he made was broken, which he had missed in a flood of Slack messages. Reported result (as claimed by the author): He says it fundamentally changed how he uses Claude and AI. Source: https://x.com/gabemulley/status/2112986479290925283 Tools they used: Claude Duet, Claude, Slack Category: Dev & ops Please: 1. Ask me 3 short questions about my situation (accounts I have, budget, what I want the output to look like). 2. Propose a step-by-step plan using these tools or cheaper alternatives, with the time and cost of each step. Use official pricing pages; say "check pricing" if unsure. 3. Then do the setup with me one step at a time, waiting for my OK before anything that sends messages, posts publicly, spends money or deletes data. 4. Finish with a checklist to run it again next time.
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