Conciseness

The body is lean and dense with MPS-specific facts Claude would not know (e.g., 'the jump is taken when the condition is FALSE', 'EmitLabelStatement.name is display-only; jumps reference the label node via LabelPosition.label'). Minor trimmable parts keep it below anchor 5: the opening paragraph partially restates the frontmatter description, and the 'Loading companion skills' section is generic loader policy rather than dataflow content. Not anchor 3 — there is no genuine over-explanation of concepts Claude already knows.

Actionability

Concrete, executable guidance throughout: 'Create the dataflow model with mps_mcp_create_model (moduleName: "<lang>", modelName: "<lang>.dataFlow")', 'Validate with mps_mcp_check_root_node_problems', and 'inspect ... via mps_mcp_print_node with deep: true', plus exact concept/role names and a case-sensitivity trap ('The aspect ID is dataFlow — camelCase, case-sensitive'). It falls short of anchor 5 only because copy-paste-ready JSON blueprints are delegated to references/json-patterns.md rather than shown inline — appropriate for a reference-type skill, so this is a minor gap, not missing detail.

Workflow Clarity

The 'Common-Path Workflow' gives a clear 6-step sequence ending in an explicit validation checkpoint ('Validate with mps_mcp_check_root_node_problems') with a debugging tip for tricky cases. It misses anchor 5 because there is no explicit error-recovery feedback loop (what to do when validation fails, other than the pointers to rules-and-pitfalls.md) — 'sequence present, checkpoint present, retry loop implicit'. Operations are node-creation rather than destructive, so no cap applies.

Progressive Disclosure

The 'Reference Index' is well-signaled with per-reference 'open when' triggers, a 'Start here — most common case' entry pointing to references/json-patterns.md, and one-level-deep links (references/aspect-model-stereotypes.md, concept-catalog.md, rules-and-pitfalls.md, setup-and-engine.md, baselanguage-builder-index.md, sample-language-reference.md) — structurally matching anchor 5. However, no references/ directory is present in the bundle, so none of the six referenced paths could be verified to exist, which is a navigation-integrity gap that keeps it at 4 rather than 5.

Specificity

The description enumerates concrete capabilities and entities: 'DataFlowBuilderDeclaration, BuilderBlock, emit instructions (code for, jump, ifjump, label, read, write, ret, mayBeUnreachable), positions (AfterPosition, BeforePosition, LabelPosition)', plus 'the NodeParameter implicit, BL+smodel usage inside builder bodies, and IBuilderMode for advanced analyses such as nullable/non-null tracking'. Coverage is comprehensive and concrete — not vague. Anchor 4 would require minor gaps in coverage; the enumerated list covers the aspect's full surface.

Completeness

It explicitly answers 'when' first — 'Use when defining or debugging MPS dataflow builders for a concept' — and 'what' concretely: 'control/data flow declarations that drive reachability analysis and variable-use checking', followed by an explicit 'Covers ...' list. Both halves are explicit with concrete trigger phrases, matching the anchor-5 good example structure.

Trigger Term Quality

Natural domain phrases are present — 'defining or debugging MPS dataflow builders', 'reachability analysis', 'variable-use checking', 'nullable/non-null tracking' — which is good keyword coverage. It falls short of anchor 5 because common user phrasings like 'unreachable code' or 'uninitialized variable' (the engine's actual diagnostics) are absent, while synonyms/extensions coverage is otherwise incomplete.

Distinctiveness Conflict Risk

A clear niche (the MPS dataflow aspect) with distinct, domain-locked triggers — dataflow builders, emit instructions, ifjump/label semantics. It is unlikely to fire for sibling MPS aspect skills (behavior, typesystem) since dataflow-engine terminology dominates; distinctness is not merely 'mostly distinct' (anchor 4) but fully niche-specific.