Fixer Agent - Stop wasting time on routine PR fixes

Code review often boils down to small, scoped problems: a formatting hiccup, a broken import, a type mismatch, or a lint rule violation. The work to fix those issues is mechanical but noisy. Authors clone, reproduce the environment, install dependencies, apply a tiny patch, run checks and push. Reviewers spend headspace policing formatting and trivial errors instead of focusing on higher level composition and correctness. That repeated work fragments flow and slows the review cycle.

Fixer treats those routine problems as composable units and automates the rework loop inside a sandboxed agent. An agent session is created in an isolated runtime that reproduces the repo environment, installs dependencies using lockfile-aware caching, and runs an agent that composes a minimal patch to address the review. After the patch is applied we run a strict, deterministic validator that only permits mechanical changes and only runs format, lint and build checks declared by the repo. If validation succeeds the orchestrator requests a write token and the runtime produces an auditable commit. If validation fails we return structured diagnostics so the reviewer and author can move the topic forward with clarity. The orchestration and runtime contract are implemented end to end so Fixer is repeatable and observable .

We made two product decisions to keep Fixer predictable and safe. First, fixes are intentionally scoped and conservative. Fixer composes mechanical edits only. It will not invent build steps, run tests that need secrets, or attempt broad refactors. The post-fix validator will stop and report whenever a failure requires a logic change rather than a mechanical adjustment . Second, we solve environment mismatch by applying a repo-level sandbox before composition. The sandbox injects encrypted env vars and runs an optional setup script so the agent composes inside the same local context the team uses. Dependency installs are deterministic and cache friendly, which makes composition reliable across runs. For this phased launch we focused on Node.js lockfiles and install commands and designed the system so new language handlers plug in cleanly .

What Fixer delivers is faster, less interrupted composition and a cleaner review flow. Review topics that used to require manual patching now move forward automatically when the change is trivial and safe. That saves reviewers and authors minutes per PR and reduces context switches, which compounds into meaningful velocity improvements for teams that handle many small review topics each week. We launched conservatively so teams can try Fixer without surprise.

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If you want early access or help mapping Fixer to your review topics, we want to work with you.