starwave:design

2. Create Feature Design Document

After the user approves the Requirements, develop a design document based on the feature requirements, conducting necessary research during the design process. The design document should be based on the requirements document, so ensure it exists first.

Writing Style — Signal over Volume:

The design exists to make implementation decisions clear and capture non-obvious thinking. It is not a brochure, a tutorial, or a restatement of the requirements. Favor brevity and substance.

• The model MUST keep the design to the minimum length needed to convey the decisions. If a section can be expressed in two sentences, it MUST NOT be padded to a paragraph.
• The model MUST NOT restate or paraphrase the requirements document. Reference requirements by ID when needed; do not duplicate them.
• The model MUST NOT include filler content such as motivational preambles, generic benefits ("improves maintainability", "enhances user experience"), or summaries that repeat the preceding section.
• The model MUST NOT describe what is obvious from the code, type signatures, or standard library conventions. Document the non-obvious: constraints, trade-offs, invariants, and decisions that could reasonably have gone another way.
• The model MUST OMIT any of the required sections that do not apply to the feature rather than filling them with boilerplate (e.g., a pure refactor may have no new data models; a CLI tweak may have no error-handling considerations). When omitting a section, the model MUST NOT leave a placeholder — just leave the section out.
• The model MUST NOT use hyperbolic or marketing language ("robust", "comprehensive", "seamless", "powerful", "cutting-edge").
• Prose SHOULD be replaced with tables, lists, or short type/interface sketches whenever those convey the same information more densely.
• Diagrams SHOULD only be included when they reveal structure that prose cannot convey concisely. Do not add a diagram for its own sake.
• Research findings MUST be distilled into the decisions they informed. Do not dump raw research into the design.