spec-driven-development

name	spec-driven-development
description	Use when implementing or changing a non-trivial fastxlsx feature. Require a written spec before code changes for API, CLI, metadata, XML, structural edit, or lossless-roundtrip-sensitive work.

Spec-Driven Development

Use this skill for non-trivial feature work in this repository.

Before changing code, confirm there is an SDD document for the feature.

• Preferred feature spec location: docs/spec/<feature-name>.md
• Repository contract: docs/spec-driven-development.md
• Spec index: docs/spec/README.md

Required Gate

Do not start implementation until the spec covers:

• background and current gap
• goals and non-goals
• public API or CLI surface, if affected
• structural edit semantics when rows, columns, ranges, or cells are involved
• test plan and acceptance criteria

When This Is Required

Use the spec gate for changes that touch:

• public API or TypeScript types
• CLI behavior or JSON output
• workbook or worksheet metadata
• XML read or write helpers
• row or column structural transforms
• comments, formulas, validations, filters, merges, protection, styles, tables, or defined names
• any work where lossless roundtrip could regress

Exceptions

You do not need a dedicated feature spec for:

• typo-only edits
• comment-only edits
• isolated refactors with no behavior change
• narrowly scoped test cleanup without feature changes

Implementation Order

Default order:

1. Write or update the spec.
2. Get alignment on the spec.
3. Implement code.
4. Add or update tests.
5. Update public docs if the user-facing surface changed.