$25 Per PR Review Is Wild - Run Claude Code on the Diff Yourself

Fazm Team··2 min read

$25 Per PR Review Is Wild - Run Claude Code on the Diff Yourself

Some AI PR review tools charge $25 per pull request. That adds up fast when you are shipping multiple PRs a day. The irony is that you can build the same thing yourself with Claude Code and a custom skill in about an hour.

The DIY Approach

The simplest version is literally just running Claude Code on the diff output. You pipe git diff main...HEAD into Claude with a prompt that says "review this code for bugs, security issues, and style." That is the core of what these $25 services do.

A more structured version uses a custom Claude Code skill - a markdown file that defines the review checklist, coding standards, and what to flag. You run it with a single command and get back structured feedback in seconds.

What a Custom Review Skill Looks Like

The skill file lives in your .claude/skills/ directory. It contains your team's specific review criteria:

  • Security: SQL injection, hardcoded secrets, input validation
  • Performance: N+1 queries, unnecessary re-renders, missing indexes
  • Style: naming conventions, file organization, test coverage
  • Architecture: separation of concerns, API contract changes

The skill runs against the diff, not the whole codebase, so it stays fast and cheap. A typical review uses maybe 10-20k tokens - pennies on the API.

When Paid Services Make Sense

Paid PR review tools add value when you need compliance audit trails, integration with specific CI/CD pipelines, or when your team does not want to maintain custom tooling. But for most teams shipping code daily, the custom approach saves thousands of dollars per month while giving you more control over what gets flagged.

The Real Takeaway

The pattern here applies beyond code review. Whenever a SaaS tool is essentially "LLM plus a prompt plus a wrapper," you can probably build your own version with Claude Code skills. The skill system is designed exactly for this - reusable, shareable AI workflows that cost tokens instead of subscriptions.

Fazm is an open source macOS AI agent. Open source on GitHub.

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