In skills/test-driven-development/SKILL.md, line 359 references a file with an @ prefix:

When adding mocks or test utilities, read @testing-anti-patterns.md to avoid common pitfalls:

The actual file lives at skills/test-driven-development/testing-anti-patterns.md (no @ prefix; the URL https://raw.githubusercontent.com/obra/superpowers/main/skills/test-driven-development/testing-anti-patterns.md returns HTTP 200).

The @ prefix is the only such reference style anywhere in this SKILL.md — every other internal file reference is written as a bare filename or a code-fenced path. There is no autolink rule in standard markdown that would resolve @testing-anti-patterns.md to the file, and there is no @-handling convention referenced in the skill's preamble. An agent reading this passage will either treat @testing-anti-patterns.md as literal text (and fail to read the file) or guess that it should resolve to testing-anti-patterns.md (correct answer, but only by inference).

Suggested fix

Replace the @-prefixed reference with a plain (or backtick-wrapped) filename so the path is unambiguous:

- When adding mocks or test utilities, read @testing-anti-patterns.md to avoid common pitfalls:
+ When adding mocks or test utilities, read `testing-anti-patterns.md` to avoid common pitfalls:

Or, if the @ prefix is meant as a convention that should be documented, add a one-line note near the top of the skill explaining that @<filename> means "the file at <filename> in this skill's folder" — and use it consistently across all internal references.