Conciseness

The body is dense and largely earns its tokens — routing table, numbered universal constraints with concrete syntax examples, exact tool parameters — but Step 4 and the reuse section carry editorial padding ("One good question beats one wasted diagram", "readers often benefit from seeing the history of attempts", "Regenerating 4 times = 4 draft files to clean up"). These are minor over-explanations that could be trimmed, matching the 4 anchor rather than the 5 ('every token earns its place') or the 3 ('several unnecessary explanations').

Actionability

Fully concrete, executable guidance throughout: exact supported type list (`flowchart`, `sequenceDiagram`, `stateDiagram` / `stateDiagram-v2`, `gantt`, `erDiagram`), an explicit unsupported list with the correct fallback ("tell them directly… instead of calling the tool and failing"), concrete Mermaid syntax examples (`A["Process (main)"]`, `-->|"O(1) lookup"|`), the exact FigJam error string to avoid, all tool parameters with usage conditions, and a `fileKey` extraction rule. Nothing is pseudocode or vague; an instruction-only skill with copy-ready specificity, matching the 5 anchor.

Workflow Clarity

A clear 7-step sequence (tool fit → type selection → universal constraints → context gathering → hybrid decision → tool call → post-generation) with explicit decision checkpoints ("When in doubt, ask the user", hybrid yes/no signals) and genuine feedback loops for error recovery: stop after 2 failed attempts and ask what's wrong, ask the user's file-reuse preference and remember it. Per-type validation checklists live in the references (e.g. architecture.md's validation-checklist section). This exceeds the 4 anchor and matches 5; the destructive/batch cap does not apply since generation is non-destructive and file proliferation is explicitly managed.

Progressive Disclosure

The body is a textbook overview/routing document: a type-selection table pointing to seven real one-level-deep reference files via markdown links, with type-specific detail (layout codes, per-type rules) correctly deferred to those files. Verified the bundle: all referenced files exist and reference files link only to sibling references or internal anchors — no nested chains. Matches the 5 anchor (clear overview, well-signaled one-level-deep references, easy navigation).

Specificity

The description lists several concrete actions — "Routes to type-specific guidance, sets universal Mermaid constraints, and tells you when to use a different diagram type or skip the tool entirely" — which would anchor at 4, but it never states the core capability (generating a FigJam diagram from Mermaid) and uses second person ("tells you when…"), which the rubric penalizes by one point. It sits above 2 ('names the domain but actions are minimal') because the actions enumerated are genuinely specific, not generic.

Completeness

Explicitly answers both questions: 'when' via "Trigger whenever the user asks to create, generate, draw, render, sketch, or build a diagram" and 'what' via routing, universal constraints, and skip guidance. Matches the 5 anchor (clear and explicit what AND when with concrete trigger phrases); a 4 would require the 'when' to be less explicit, which it is not.

Trigger Term Quality

Comprehensive natural-term coverage with synonyms and variations: "create, generate, draw, render, sketch, or build a diagram — flowchart, architecture diagram, sequence diagram, ERD or entity-relationship diagram, state diagram or state machine, gantt chart, or timeline" plus "Mermaid syntax", "decision tree", "dependency graph", "API call flow", "auth handshake". These are exactly the phrases a user would naturally say; nothing common is missing, so the 4 anchor ('a few natural terms missing') does not fit.

Distinctiveness Conflict Risk

Clear niche anchored to the specific `generate_diagram` tool, Mermaid syntax, and FigJam output, with explicit negative triggers ("mindmaps, pie charts, class diagrams"). Minimal conflict risk with other skills; the specificity of the tool name exceeds the 4 anchor's 'minor overlap risk with closely related skills'.