Conciseness

The body is lean and assumes Claude's competence — it gives the process, slice rules, and a template without explaining what a PRD is, what tracer bullets mean in general, or padding with generic prose. Every section earns its place, matching the score-5 'lean and efficient' anchor.

Actionability

It provides concrete, executable guidance: a numbered 6-step process, explicit rules for slices, and a full copy-paste-ready plan template with phase/acceptance-criteria structure. As an instruction-only skill the guidance is actionable and specific, though it leaves some judgment (e.g., exactly which stories per phase) to the model, keeping it just below 5.

Workflow Clarity

The 6-step process is clearly sequenced with an explicit validation/feedback checkpoint — 'Iterate until the user approves the breakdown' (step 5) and 'Confirm the PRD is in context' (step 1) — providing the quiz-iterate loop that catches errors before writing the file. This matches the score-5 anchor of a clear sequence with explicit feedback loops.

Progressive Disclosure

The skill is under 50 lines with no need for external references, and is organized into well-labeled sections (Process, vertical-slice-rules, plan-template). Per the simple-skills scoring note, a well-organized short skill with no external references scores 5.

Specificity

It names the domain (PRD breakdown) and several concrete actions — 'Turn a PRD into a multi-phase implementation plan using tracer-bullet vertical slices, saved as a local Markdown file in ./plans/' — listing the output format and methodology, with only minor coverage gaps (e.g., it doesn't enumerate reviewing/quiz steps). It lists multiple specific concrete actions but stops short of comprehensive coverage, matching the score-4 anchor rather than score-5.

Completeness

It explicitly answers both 'what' ('Turn a PRD into a multi-phase implementation plan... saved as a local Markdown file in ./plans/') and 'when' ('Use when user wants to break down a PRD, create an implementation plan, plan phases from a PRD, or mentions "tracer bullets"') with concrete trigger phrases, matching the score-5 anchor exactly.

Trigger Term Quality

Natural trigger phrases are present — 'break down a PRD', 'create an implementation plan', 'plan phases from a PRD', 'tracer bullets' — giving good keyword coverage a user would naturally say. A few common synonyms or variants (e.g. 'roadmap', 'sprint plan') are missing, so it sits at 4 rather than 5.

Distinctiveness Conflict Risk

The 'tracer bullets' framing and PRD-to-plan niche give it a clear, fairly distinct trigger set with minimal conflict risk, though the broad phrase 'create an implementation plan' could overlap with general planning skills, keeping it just below 5.