Conciseness

The language is tight and free of explaining known concepts, but several sections restate earlier material: "Key Principle" repeats the Overview's core principle, "Real Example: Empty projectDir" re-walks the same git-init scenario from "The Tracing Process", and "Real-World Impact" ("1847 tests passed, zero pollution") is session-specific padding. Not a 2 because no section explains concepts Claude already knows and the code earns its place.

Actionability

Concrete, executable guidance throughout: a copy-ready TypeScript instrumentation snippet ("const stack = new Error().stack; console.error('DEBUG git init:', {...})") and runnable commands ("bun test 2>&1 | grep 'DEBUG git init'", "bun test --run --bail | tee test-output.log"). Not a 5 because "Use the bisection script" references a script that does not exist in the bundle, and `bun test --run --bail` does not actually run tests one-by-one as claimed ("Runs tests one-by-one, stops at first polluter").

Workflow Clarity

The five-step sequence (Observe the Symptom → Find Immediate Cause → Ask: What Called this? → Keep Tracing Up → Find Original Trigger) is clearly ordered, with capture/analysis checkpoints (grep the debug output, tee the test log, analyze stacks for test names and line numbers). Not a 5 because the process lacks an explicit verify-the-fix step and the bisection section's description mismatches its command; not a 3 because the sequence is coherent and checkpoints like 'Run and capture' are explicit.

Progressive Disclosure

A single, well-sectioned SKILL.md with clear headers and no bundle files (no references/, scripts/, or assets/ exist), and no nested or buried references — nothing needs external splitting for a single-process debugging skill. Not a 5 because at ~130 lines it exceeds the simple-skill case (under 50 lines), and sections like "Real Example" and "Real-World Impact" could live in a reference file; not a 3 because the structure is unambiguous and easy to navigate.

Specificity

"Systematically trace bugs backward through call stack to find original trigger" names the domain (bug tracing) and one concrete action, but offers no broader set of specific actions (e.g., instrumenting code, analyzing stack traces). It sits above the generic 'Processes PDF files' level but below the 'several specific actions' anchor.

Completeness

Both parts are present: the 'what' ("Systematically trace bugs backward through call stack") and an explicit 'when' ("Use when errors occur deep in execution"). Not a 5 because the 'when' clause is partly circular ("you need to trace back to find the original trigger") and lists few concrete trigger situations; not a 3 because the 'when' is explicit, not merely implied.

Trigger Term Quality

Relevant phrases like "call stack", "errors occur deep in execution", and "trace back" exist, but common natural synonyms users would say — "root cause", "stack trace", "debug" — are missing. Coverage is partial rather than good (4) or comprehensive (5).

Distinctiveness Conflict Risk

Root-cause/backward tracing occupies a clear niche ("trace bugs backward through call stack") with triggers tied to deep execution errors, so it is mostly distinct. Minor overlap risk with general debugging skills keeps it below a 5.