Test Harness

Three tiers for testing Claude Code harnesses, cheapest first: unit tests for hook logic (free, no model), deterministic tests for wiring and context injection (free, scripted mock), and evals for trigger precision and behavioral shifts (paid, real model). Most harness questions never need a model. You can verify a PreToolUse hook blocks the right commands, confirm injected context reaches the prompt, or measure whether a skill description fires too often, all with the right tier. The skill installs vigiles, picks the tier that can actually answer your question, writes the test, and runs it. Start cheap and climb only when the question genuinely requires a real model.

Install to Claude Code

npx -y skills add zernie/vigiles --skill test-harness --agent claude-code