Mostly efficient with no padding of basic concepts Claude already knows, but the per-workflow 'Task Progress' checklists restate the adjacent numbered steps and a table of contents on a ~145-line doc adds overhead that could be tightened.

Three complete, executable Dart examples (User model with fromJson/toJson, synchronous fetch, background `compute()` parsing) that are copy-paste ready with real imports and casts.

Both workflows are numbered with checklists; the fetch workflow has an explicit conditional branch (small vs large payload → sync vs isolate) and a validate→fix feedback loop ('Run validator -> review type mismatch errors -> fix casting logic'), plus HTTP status validation that throws on failure.

Well-sectioned with a navigation TOC, but everything is inline in a single ~145-line file with no external references; the three full code examples are content that could reasonably be split into a referenced examples file. The under-50-line simple-skill exception does not apply here.

Lists multiple concrete actions — 'Create model classes with `fromJson` and `toJson` methods using `dart:convert`' — naming specific methods and the library, matching the multi-action anchor.

Explicitly answers both what ('Create model classes with fromJson and toJson') and when ('Use when manually mapping JSON keys to class properties'), with an explicit 'Use when' trigger clause.

Relevant keywords ('JSON keys', 'class properties', 'fromJson', 'toJson') are present but lean technical; common natural variations a user might say ('parse JSON', 'API response', 'deserialize', 'serialize') are missing.

The niche is narrow — Flutter + manual JSON via `dart:convert` for 'simple data structures' — which clearly separates it from codegen skills (json_serializable, freezed) and is unlikely to trigger for the wrong skill.