Conciseness

The body is lean: terse bullet lists, no concept explanations Claude already knows, and every section earns its place. However, the 10-category enum is duplicated between 'Classify the Root Cause' and the Output Format template, and NEXT_ACTION guidance is spread across three sections ('Determine the Smallest Safe Next Action', 'Determine Whether the Task Plan Is Still Valid', 'Stop / Escalate'), which could be consolidated. This matches anchor 4 (minor instances that could be trimmed) rather than anchor 5's 'every token earns its place'.

Actionability

Guidance is concrete for an instruction-only skill: exact inputs to gather, output fields with enum values, decision rules for RETRY/BLOCK/STOP, and a copy-paste Markdown report template. It stops short of anchor 5 because there is no worked example of a filled debug report or sample verification commands covering a common case, leaving a minor gap.

Workflow Clarity

The six-step method is clearly sequenced (read error, inspect repo, search web, classify, choose action, validate plan) with explicit escalation criteria and a feedback loop via NEXT_ACTION: RETRY_TASK. The checkpoint confirming the root-cause hypothesis against gathered evidence before classifying is only implicit in the Critical Rule ('Identify the root cause first'), so it fits anchor 4 (clear sequence, most checkpoints present) better than anchor 5's explicit validation steps.

Progressive Disclosure

No bundle files exist; the skill is a single ~145-line file with clear ## and ### section headers and no buried or nested references, so nothing is misplaced. Because all content is inline with section headers as the only navigation and the file exceeds the under-50-line simple-skill case, it fits anchor 4 (good structure, minor organization gaps) rather than anchor 5's well-signaled multi-file split.

Specificity

The description names the domain ('implementation failures', 'root-cause-first debugging') and a single concrete action ('Investigate'), but lists no other capabilities or outputs (e.g., root cause reports, fix plans, escalation decisions). It matches the anchor for 1-2 concrete actions without comprehensive coverage; it falls short of anchor 4, which requires several specific actions listed.

Completeness

Both 'what' ('Investigate implementation failures using root-cause-first debugging') and 'when' ('Use when an implementer is blocked, verification fails, or repeated remediation does not converge') are explicitly present with concrete triggers. The 'what' is a single verb phrase that omits what the skill produces (ROOT_CAUSE, FIX_PLAN, NEXT_ACTION outputs), so it does not fully reach the comprehensiveness of anchor 5.

Trigger Term Quality

'implementer is blocked', 'verification fails', and 'repeated remediation does not converge' are natural phrases a user would say when needing this skill. Coverage is good but misses common variations like 'error', 'build fails', or 'task fails', placing it between anchors 4 and 5, closer to 4.

Distinctiveness Conflict Risk

Root-cause investigation for blocked implementers and non-converging remediation is a distinct niche within an orchestrated agent pipeline, with trigger terms unlikely to fire for unrelated skills. There is minor overlap risk with a general-purpose debugging skill, keeping it below anchor 5.