skill提交

.agents/skills/tdd/SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: tdd
-description: Test-driven development with red-green-refactor loop. Use when user wants to build features or fix bugs using TDD, mentions "red-green-refactor", wants integration tests, or asks for test-first development.
+description: Test-driven development. Use when the user wants to build features or fix bugs test-first, mentions "red-green-refactor", or wants integration tests.
 ---
 
 # Test-Driven Development
@@ -13,6 +13,8 @@ description: Test-driven development with red-green-refactor loop. Use when user
 
 **Bad tests** are coupled to implementation. They mock internal collaborators, test private methods, or verify through external means (like querying a database directly instead of using the interface). The warning sign: your test breaks when you refactor, but behavior hasn't changed. If you rename an internal function and tests fail, those tests were testing implementation, not behavior.
 
+**Tautological tests** restate the implementation inside the assertion, so they pass by construction and give zero confidence. When the expected value is computed the way the code computes it — `expect(add(a, b)).toBe(a + b)`, snapshotting a figure you derived by hand the same way the code does, asserting a constant equals itself — the test can never disagree with the code: break the code wrong and the assertion breaks wrong with it. The expected value must come from an independent source of truth — a known-good literal, a worked example, the spec.
+
 See [tests.md](tests.md) for examples and [mocking.md](mocking.md) for mocking guidelines.
 
 ## Anti-Pattern: Horizontal Slices
@@ -44,14 +46,13 @@ RIGHT (vertical):
 
 ### 1. Planning
 
-When exploring the codebase, use the project's domain glossary so that test names and interface vocabulary match the project's language, and respect ADRs in the area you're touching.
+When exploring the codebase, read `CONTEXT.md` (if it exists) so that test names and interface vocabulary match the project's domain language, and respect ADRs in the area you're touching.
 
 Before writing any code:
 
 - [ ] Confirm with user what interface changes are needed
 - [ ] Confirm with user which behaviors to test (prioritize)
-- [ ] Identify opportunities for [deep modules](deep-modules.md) (small interface, deep implementation)
-- [ ] Design interfaces for [testability](interface-design.md)
+- [ ] Identify opportunities for deep modules (small interface, deep implementation) — run the `/codebase-design` skill for the vocabulary and the testability checks
 - [ ] List the behaviors to test (not implementation steps)
 - [ ] Get user approval on the plan
 
@@ -104,6 +105,7 @@ After all tests pass, look for [refactor candidates](refactoring.md):
 [ ] Test describes behavior, not implementation
 [ ] Test uses public interface only
 [ ] Test would survive internal refactor
+[ ] Expected values are independent literals, not recomputed from the code
 [ ] Code is minimal for this test
 [ ] No speculative features added
 ```