From spec-coexist
Use whenever the user wants to CREATE a new detailed design document — whole-system (`docs/main-detail-design/index.md`) or subsystem (`docs/subsystems/{id}_{name}/detail-design/index.md`, including nested subsystems like `docs/subsystems/.../subsystems/{id}_{name}/detail-design/index.md`). Trigger on phrases like "詳細設計を作る", "詳細設計書を書きたい", "detail design を作って", "draft a detailed design", "create detail design", "モジュールの振る舞いを設計したい". Do NOT trigger for updates to existing detailed design documents — use `spec-coexist:revising` instead. This skill MUST NOT update existing detail design files — it only creates new ones — and MUST halt if the corresponding basic design document does not exist. This skill is self-contained and MUST NOT delegate to any `superpowers:*` skill.
How this skill is triggered — by the user, by Claude, or both
Slash command
/spec-coexist:creating-detail-designThe summary Claude sees in its skill listing — used to decide when to auto-load this skill
Conformance keywords follow [RFC 2119](https://www.rfc-editor.org/rfc/rfc2119) / [RFC 8174](https://www.rfc-editor.org/rfc/rfc8174).
Conformance keywords follow RFC 2119 / RFC 8174.
This skill MUST NOT invoke or delegate to any superpowers:* skill. It MUST invoke the project-local code-review-loop.
Create a brand-new detailed design document (whole-system or subsystem). For updates to existing documents, use spec-coexist:revising instead.
../_shared/templates/README.md. ja loads templates from references/; en loads from ../_shared/templates/en/.check_doc_exists.sh on the basic design. If absent, HALT. See references/constraints-and-review.md.detail-design/index.md already exists at target, HALT. See references/constraints-and-review.md.references/. Also load references/module-template.md.references/folder-structure-guidelines.md. Confirm with user.references/brainstorming-rules.md. Process one module at a time, using Mermaid diagrams as the primary notation.index.md and per-module files. Mermaid is primary; code ONLY when diagrams cannot prevent drift. The drafted text MUST apply the 7 readability elements in ../_shared/references/document-readability.md. See template rules.check_doc_links.sh --root docs --strict. Fix all errors.verification-before-completion (document mode).code-review-loop. See references/constraints-and-review.md §Mandatory Design Review.Review: outcome line.flowchart TD
Start([Skill invoked]) --> Q1{Basic design<br/>exists?}
Q1 -- No --> Stop([HALT])
Q1 -- Yes --> R[Read basic design]
R --> T{Whole-system or<br/>subsystem?}
T --> Q2{detail-design/<br/>index.md exists?}
Q2 -- Yes --> Stop
Q2 -- No --> Plan[Plan folder structure<br/>+ confirm modules]
Plan --> BS[Brainstorm per module]
BS --> Write[Write index + module files]
Write --> Verify[verification-before-completion]
Verify --> Review[code-review-loop]
Review --> End([Done])
When writing Mermaid diagrams, consult ../_shared/beautiful-mermaid-rules/ and follow its guidance.
../_shared/references/document-readability.md — 7-element readability framework applied during writing and verificationreferences/constraints-and-review.md — hard constraints, verification gate, review protocolreferences/brainstorming-rules.md — one-question-per-message, module-by-module approachreferences/folder-structure-guidelines.md — multi-file organization rulesreferences/module-template.md — per-module file structurereferences/main-detail-design-template.md — whole-system index template (ja)references/main-detail-design-template-rules.md — whole-system authoring rules (ja)references/subsystem-detail-design-template.md — subsystem index template (ja)references/subsystem-detail-design-template-rules.md — subsystem authoring rules (ja)../_shared/scripts/check_doc_exists.sh <path>../_shared/scripts/check_doc_links.sh --root docs --strict../_shared/scripts/resolve_subsystem_path.sh <qualified-id>../_shared/scripts/gen_questions_path.sh detail-designnpx claudepluginhub wintermaples/spec-coexist --plugin spec-coexistProvides behavioral guidelines to reduce common LLM coding mistakes, focusing on simplicity, surgical changes, assumption surfacing, and verifiable success criteria.
Searches, retrieves, and installs Agent Skills from prompts.chat registry using MCP tools like search_skills and get_skill. Activates for finding skills, browsing catalogs, or extending Claude.
Creates, edits, and optimizes skills for Claude Code, including drafting, evaluating with test prompts, iterating on performance, and improving skill descriptions for better triggering accuracy.