Rules that run
When Codex reads a rule, an AI decides whether your code follows it. When Breakspec checks a rule, your code runs, and either passes or shows you an example that fails.
Compare · Checked 12 October 2026
Breakspec vs Codex code review
Codex can review every pull request, or one you tag with @codex review. You tell it what to look for in a file called AGENTS.md, and commenting @codex fix it starts a task to fix what it found. Those instructions are read by an AI. Breakspec’s rules are checked by running your code.
What Codex code review does
- Reviews automatically or when asked, and comments on problems like regressions and missing tests.
- You write review rules in a “Code Review Rules” section of AGENTS.md.
- Commenting @codex fix it starts a task that fixes the problem and updates the pull request.
How Breakspec is different
Fixes get checked the same way
After a fix, Breakspec reruns the example that failed and every other rule. A fix that only special-cases that one example doesn’t count.
Works with any agent
Breakspec checks code from Codex, Claude Code, Cursor or a person.
| Codex code review | Breakspec | |
|---|---|---|
| How it finds bugs | An AI reads the change | Runs your code on hundreds of examples |
| What you get back | A comment about what might be wrong | An example that breaks your code, which you can run yourself |
| Who decides what “correct” means | The AI, guided by your instructions | You, by approving rules |
| Cost of checking every pull request | Uses AI on every review | No AI cost. Rechecking doesn’t use AI |
| After a fix | Reviews the new code again | Reruns the example that failed, and notices if the fix cheats |
What Codex code review does better
- If you already use Codex, it’s one setting.
- It can fix what it finds without leaving the pull request.
Can I use both?
Yes. Keep Codex reviewing, and add Breakspec so your most important rules get run, not just read.
Sources
Checked on 12 October 2026, from Codex code review’s own docs and pricing pages. Prices and features change; if something here is out of date, tell us at sales@breakspec.com and we’ll fix it.
Other comparisons
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