What problem does it solve? Technical specifications for models, API endpoints, flows, and architecture diagrams often end up scattered, inconsistent, or missing entirely, leaving implementers to guess. This Skill produces structured, per-capability technical documentation in docs/architecture/ with stable identifiers (MD-XXX, API-XXX, FL-XXX, DG-XXX) that user stories, technical tasks, and maintenance tasks can reference as implementation sources. ## Core Features & Use Cases - Capability-based organization: Each capability gets a folder with an index README plus models/, apis/, flows/, and diagrams/ subfolders, one file per element with stable sequential IDs. - Grouped API contracts: Endpoints are grouped by entity or functionality (e.g., full CRUD of a resource in one API-XXX file), each operation carrying an explicit method+route anchor for precise cross-referencing. - Structured gap grilling: Before writing, the Skill asks targeted questions about missing types, error codes, flow branches, and auth rules, logging unresolved gaps in Observations instead of inventing data. - Delegated mode: Other skills (work-define, work-plan) can invoke it via subagent to produce technical specs and receive ready-to-insert file references. - Use Case: While defining a user story for credit notes, the Skill creates MD-003 (credit note model) and API-002 (credit notes endpoint group) under docs/architecture/facturacion/ and returns the references for the story's References section. ## Quick Start Ask the agent to document the data model and API endpoints for the invoicing capability using the design-define skill.