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Open an issue.Approve the fix.

Patchwise reads a GitHub issue, proves the bug with a failing test, fixes it in a locked-down sandbox, and then stops. Nothing reaches your repository until you approve the exact diff.

Early access for Python repositories. Built on Claude.

slugger / issue #3Example run
Issue
slugify("!!!") raises IndexError instead of returning an empty slug
Reproduce
$ pytest tests/test_slug_empty.py
FAILEDtest_symbol_only_title_gives_empty_slug
Fix slugger/slug.py
words = [w for w in words if w]
+ if not words:
+ return ""
if words[0].isdigit():
Verify
$ pytest
PASSEDreproduction test and full suite

Waiting for your approval

How a fix happens

Every run follows the same four steps, in order. If a step fails, Patchwise retries within its budget or stops and tells you why.

  1. Reproduce

    It writes a test that fails on your current code. No failing test, no fix.

  2. Fix

    It plans a change, then edits only what the plan names, inside a container with no internet access.

  3. Verify

    Your test suite runs again. Pass or fail comes from the test results, never from the model saying so.

  4. You approve

    You see the diff, the test results and anything worth a closer look. Approve, and Patchwise opens a draft pull request.

What Patchwise can't do

An agent that edits your code should have hard limits, not just good intentions. These are enforced by the system around the model, so a cleverly worded issue can't talk its way past them.

  • Push or mergeIt opens draft pull requests, and only after you approve.
  • Reach the internet while running your codeEach command runs in its own container with networking off.
  • Read your secretsYour GitHub token never enters the sandbox.
  • Weaken the test to make it passThe reproduction test is read-only to the step that writes the fix.
  • Sneak in a different changeYour approval is tied to the exact diff you reviewed. If it changes, you review again.
  • Run up your billSteps, tokens, cost and time are capped and checked before every action.

You see everything before you approve

The review screen shows the change, the new test, and which checks passed. Every model call, command and test result is recorded, so you can see why each change was made.

Review screen showing a diff that adds an empty-words check to slugify, a new test file, and validation results with the reproduction test and test suite both passed

A real run from the prototype, which is open source as DevAgent. See it on GitHub

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