---

name: "typescript-code-review" description: "Review a TypeScript change for unsafe assertions, missing runtime checks, and compiler-API assumptions. Use for a TypeScript code review. Do not use for a non-TypeScript repository or to turn on a new compiler unasked."

TypeScript Code Review

Shared skill typescript-code-review for TypeScript. Codex and Antigravity CLI both read .agents/skills/typescript-code-review/SKILL.md. Install this one file. Codex calls it with $typescript-code-review or /skills. Cursor, GitHub Copilot, and Devin also read .agents/skills. A second copy with the same name collides. Do not install another tool's file there.

When to run

Run this review on a TypeScript change, a pull request, or a request to "check the types". Look for holes in the checker and for runtime data that was never parsed.

When to leave it

Stop for a repository without TypeScript, or for a formatting-only diff. Do not upgrade the compiler unless the user asked.

Steps

1. Read the installed typescript version and whether strict is on. A script that imports compiler APIs from the 7.0 typescript package is a high finding: 7.0 does not ship that API. Point it at @typescript/typescript6, or wait for a real 7.1 API. A plan to jump majors without a request is a finding, not a task you start.
2. Search the diff for any, as , !, and @ts-ignore or @ts-expect-error without a reason. Each one at a boundary is a finding. An assertion immediately after a proper parse can stay.
3. Find functions that accept unknown or external JSON and return a typed value without a parser. That is a finding.
4. Check unions. A switch that falls through to a default which returns any is a finding. An exhaustive switch can stay.
5. If the diff touches a script that imports typescript as a library, confirm the calls exist on the installed major. Missing methods are a high finding.
6. Run the project's typecheck when the user asked for a check. Record the command. Otherwise write not run.

Output

Findings first, with file, line, the unsafe construct, and a narrower type or a parser. Then the compiler version and no file edits unless a fix was requested.

## Findings
- high | path:line | what is wrong | what to do instead

## No findings
Say "No findings" and list the files you opened. A search you skipped is not a clean result.

## Example
Input: `src/area.ts` imports `typescript` from the 7.0 package and calls `ts.createProgram`.
Output: high | src/area.ts:1 | TypeScript 7.0 has no stable compiler API | import `@typescript/typescript6` until 7.1, or run `tsc --noEmit` instead.

Do not flag the valid pattern named in the standards. Flag the mistake next to it.

Stop

Stop when the project is not TypeScript, or when the user asks you to disable strict to get a green build.

Severity

high is a bug a caller can hit or a secret that leaks. medium is a broken contract that needs a specific input. low is a cleanup that does not change behaviour.