An open-source Sentry alternative built for AI-written code
Sentry answers “what did the code throw?” Mushi Mushi answers “what did the user hit, why did it happen, and what’s the fix?” If your app was largely written by Cursor, Claude Code, or another agent, the second question is the one you actually need answered — you didn’t write the code, so a raw stack trace costs you an afternoon of archaeology.
Mushi is open source (MIT SDKs, AGPLv3 server), works standalone, and turns a user’s bug report into a plain-English diagnosis with a fix you can paste into your editor.
When Mushi replaces Sentry — and when it doesn’t
You can run Mushi instead of Sentry if what you care about is user-reported friction: broken buttons, dead flows, confusing states. You should run Mushi alongside Sentry if you also want crash-level telemetry — an optional bridge links Sentry stack traces to Mushi reports so each side keeps its job.
Side by side
| Question | Sentry alone | Mushi |
|---|---|---|
| What it sees | Errors your code throws | Friction your users feel |
| What lands in your queue | A stack trace | A short user note plus the screenshot they were looking at |
| Repeat bugs | Each one shows up as a new issue | The same broken button collapses to one row |
| What you learn from fixes | None — the next dev repeats the mistake | Past fixes become rules your editor sees on the next PR (.mushi/lessons.json) |
| Closing the loop | Assign a ticket and remember to update | An optional draft PR you can merge or ignore, once GitHub is connected |
| Reporter attribution | Anonymous | "Fixed by Kenji" in the changelog and an SDK toast, once Releases is enabled |
| From your IDE | Copy the issue ID into Cursor | Cursor reads the report + relevant lessons and proposes the diff |
| Where it runs | Their cloud | Yours, ours, or both |
What “diagnosis” means here
When a report lands, Mushi reads the report, the screenshot, and your repo, then writes what broke and why in the language you’d use to explain it to a teammate — plus a fix prompt scoped to the files involved. Twenty reports about the same broken checkout button collapse into one row, and past fixes become lessons your editor sees on the next PR.
Try it on your app
One command detects your framework, installs the SDK, and writes your env vars:
npx mushi-mushiThe free tier includes 50 diagnoses a month with no card, and you can self-host the whole stack with one command if you’d rather keep everything on your own infrastructure.
Next: Run the incident-loop quickstart or connect your editor over MCP.