← Retour aux guides

Claude Code Review: From Risky Diff to Safe Refactor

The useful way to use Claude Code for code review is not to ask it to improve an entire repository. Give it a bounded change, require evidence for its findings, and separate diagnosis from editing. Here is a workflow for reviewing a TypeScript checkout change that mixes discount validation, tax calculation, and invoice formatting.

1. Connect Claude Code and set boundaries

59API provides low-cost, pay-as-you-go access compatible with Claude Code. Its API base URL is https://api.59api.com. Configure Claude Code's ANTHROPIC_BASE_URL and authentication environment variables according to 59API's current setup instructions; Claude Code supports ANTHROPIC_AUTH_TOKEN for token-based authentication. Keep credentials outside the repository and never paste them into review prompts.

Choose a supported model using the exact API identifier in the 59API dashboard rather than guessing an identifier from its display name. Claude Sonnet 5.5 is one available option for this workflow. 59API offers native, official-quality models without downgrades, with usage-based billing that suits occasional reviews. You can sign up and try it on a small pull request before expanding your usage.

Before sending proprietary code through any relay, confirm your organization's data-handling rules. Keep Claude Code's permission checks enabled, and inspect requested commands rather than granting unrestricted execution.

2. Establish a reproducible review scope

Start on the feature branch under review. Run git status --short and resolve or deliberately preserve any uncommitted work. Then run git fetch origin and git merge-base origin/main HEAD. Save the returned commit hash as your review baseline.

Inspect git diff --stat BASE..HEAD, replacing BASE with that hash. This scopes the review to the branch's changes since its common ancestor, rather than unrelated changes recently added to main. Run the repository's documented type checks and tests now, recording existing failures.

Launch claude from the repository root. Ask it to read the project instructions, package scripts, and changed checkout files before drawing conclusions.

3. Request findings, not immediate fixes

Review prompt: Review the diff from BASE to HEAD for correctness and regression risks. Focus on discount eligibility, rounding, tax ordering, and public return types. Read relevant callers and tests. Do not edit files. For each finding, provide severity, file and line, a concrete failing input, and the expected behavior supported by code or requirements. Separate confirmed bugs from questions.

This prompt forces useful evidence. For example, a finding that discounts are applied after tax needs an established business rule; it is not automatically a bug. Likewise, a claim about floating-point rounding should include values that actually reproduce the discrepancy.

Verify every finding yourself. Open the cited lines, follow callers, and reject recommendations based on imagined requirements. Prioritize observable regressions over stylistic preferences.

4. Add tests that prove the behavior

Choose one confirmed issue before refactoring. Ask Claude Code to propose a regression test using the project's existing framework and fixtures, then review the patch before running it.

• Cover the failing input identified during review.
• Include an ordinary purchase that must remain unchanged.
• Check boundary cases such as zero totals, missing discounts, and rounding thresholds.
• Assert public outputs, not private helper implementation details.

Run the focused test using the repository's documented command. For a bug fix, confirm the regression test fails for the expected reason before applying the fix. For behavior-preserving refactoring, establish passing characterization tests first.

5. Refactor in one bounded step

Refactoring prompt: Extract invoice-total calculation into a pure helper. Preserve the public signature, return shape, rounding behavior, and existing validation order. Do not change dependencies or unrelated files. Explain any behavior change before implementing it.

Review git diff immediately afterward. Keep the confirmed bug fix separate from mechanical cleanup where practical. Avoid accepting a broad rewrite simply because the new version looks shorter.

6. Verify independently and leave a review trail

Run focused tests, the relevant suite, type checking, and linting. Use git diff --check to catch whitespace errors, then inspect the final diff yourself. Ask Claude Code for a final review against the original constraints, but treat that as additional scrutiny, not independent proof.

Summarize the confirmed defect, preserved behavior, commands run, and unresolved questions in the pull request. Keep costs predictable by reviewing one subsystem at a time and avoiding repeated full-repository analysis. The result is a smaller, explainable change with evidence a human reviewer can verify.

Tarifs · Docs