Conciseness

The body is dense and imperative with zero concept explanations Claude already knows — every section carries project-specific signal (layer order, forbidden syntax, exact commands). It falls short of the top anchor because references are listed twice ('Referencias (leer solo cuando aplique)' and 'Project invariants (read on demand)' both enumerate reference files) and the runtime-quality checklist is flagged OBLIGATORIO in two separate sections, padding that could be merged.

Actionability

Guidance is fully executable: exact commands ('make extraction-contract', 'cd backend && .venv/bin/pytest tests/architecture/ -x -q', 'make arch-test'), copy-paste-ready code for SQLAlchemy 2.0 (correct vs prohibited), a typed Pydantic v2 DTO, and idempotent raw-SQL Alembic migrations. Concrete commands cover the common cases of each task type.

Workflow Clarity

Three task types each have a clearly sequenced workflow with explicit validation checkpoints: TDD RED tests required per layer before implementation ('escribir test que falla (RED) antes de implementar. Orden: domain → infra → app'), bugs require 'test de regresión que reproduce el bug (DEBE fallar RED). NO corregir hasta tener test rojo', and the ETL block mandates post-implementation verification with an architectural test that 'falla si saltas estos pasos'. Fitness tests and the pre-commit checklist close the loop.

Progressive Disclosure

Good structure: the SKILL.md is an overview with one-level-deep references, all listed files exist in references/ (architecture-rules.md, database.md, testing.md, standards.md, runtime-quality-checklist.md, backend-quality.md, etc.), and 'leer solo cuando aplique' / 'read on demand' signal when to load each. Minor gaps: the runtime-quality-checklist link uses a broken path ('backend-expert/references/runtime-quality-checklist.md' instead of references/), and the two separate reference sections could be consolidated for easier navigation.

Specificity

The description lists five concrete, non-overlapping actions — 'Implements FastAPI endpoints, creates SQLAlchemy 2.0 async models, generates idempotent Alembic migrations, structures bounded contexts following DDD', 'produces typed Pydantic v2 DTOs' — with no vague filler. Coverage of the skill's scope is comprehensive, matching the top anchor for multiple specific concrete actions.

Completeness

It explicitly answers 'what' (five concrete capabilities plus the runtime environment 'Runs inside Docker (visionarias_brain_dev)') and 'when' via an explicit 'Use when:' clause with a dozen concrete trigger phrases. This matches the anchor example of clearly answering both what and when.

Trigger Term Quality

Trigger phrases are natural user utterances in two languages ('create an endpoint', 'fix a backend bug', 'add a migration', 'agrega un campo', 'nueva ruta API') plus technology-name variants ('any Python/FastAPI/SQLAlchemy/Alembic task'), covering synonyms comprehensively. A user asking for any of these would naturally phrase it this way.

Distinctiveness Conflict Risk

The stack-specific niche (FastAPI/SQLAlchemy 2.0/Alembic/DDD bounded contexts, a named Docker runtime) is clearly distinct, but the trailing catch-all 'or any Python/FastAPI/SQLAlchemy/Alembic task' broadens it to overlap with any other Python-related skill. It is mostly distinct with minor overlap risk, not the minimal-conflict top anchor.