MUSUBI experimental

Core approach

Rigor turned all the way up. Work is governed by nine "immutable" constitutional articles — test-first, EARS requirement syntax with REQ-XXX-NNN IDs, 100% requirements → design → code → test traceability — enforced by a constitution-enforcer skill and audited by dedicated CLIs (musubi-trace, musubi-gaps). Spec artifacts live under storage/ (specs, design, tasks, validation reports), project memory under steering/, and every generated document is produced bilingually in English and Japanese. The README credits six predecessor frameworks, taking constitutional governance from Spec Kit and delta specs from OpenSpec, and orchestrates roughly 25 specialized agent skills across the lifecycle.

Workflow

1. npx musubi-sdd init — scaffold commands, steering, and templates for the chosen agents (or musubi-onboard to reverse-engineer steering docs from an existing codebase)
2. /sdd-steering — generate project memory (structure, tech stack, product context, rules)
3. /sdd-requirements — EARS-format requirements with unique requirement IDs
4. /sdd-design — design document with C4 model and ADRs
5. /sdd-tasks — task breakdown
6. /sdd-implement — test-first implementation
7. /sdd-validate — constitutional-compliance check
8. Brownfield track — /sdd-change-init with automatic impact analysis, then /sdd-change-apply and /sdd-change-archive, using ADDED/MODIFIED/REMOVED requirement deltas
9. Per-stage review gates — /sdd-review-requirements, /sdd-review-design, /sdd-review-implementation

Supported tools

• Claude Code
• GitHub Copilot
• Cursor
• Gemini CLI
• Codex
• Qwen Code
• Windsurf

Notes

MUSUBI is the maximalist pole of the SDD spectrum — 2026 framework surveys use it as the rigor-extreme datapoint opposite the lightweight, high-adoption kits. It is explicitly a synthesis play: the README credits six predecessors, taking constitutional governance from Spec Kit and delta specs from OpenSpec, then turning both up — the constitution ships in a file literally marked “Immutable”, and traceability is a CLI-enforced 100% requirement rather than an aspiration. As evidence for the observatory it cuts both ways: proof that full requirements → design → code → test traceability can be tooled end-to-end by a single author, and — with a few dozen stars, a repo quiet since January 2026, and that author already building a successor — a datapoint that maximal rigor has not yet found an adopter base to sustain it.

Added Jul 18, 2026 · Assessment last reviewed Jul 18, 2026 · How we track