Claude Code Output Validation Hooks in 2026: Linting Agent-Written Code Before It Touches Your Repo

This article was written with the assistance of AI, under human supervision and review.

AI code agents produce output at a pace that makes manual review impractical. A Claude Code session can edit fifty files before the first test runs. The code lands in the repository clean or broken depending on whether validation happened before the commit. Most teams discover this after the damage shows up in CI.

The problem sits between the agent's tool execution and the repository state. Claude writes code that passes its internal checks but fails the toolchain's stricter rules. Type errors appear that TypeScript would have caught. Tests break that were passing ten minutes earlier.…