Open Source · MIT
SDD Harness
Governance for teams building with AI agents
Open source · v0.20.0
SDD Harness (@e-burgos/sdd-harness) is an open source (MIT) CLI published on npm that sets up repositories so AI agents build software with traceability, following the Spec-Driven Development methodology Esteban designed and maintains.
It is used to start a new project (Nx monorepo or standalone app) or to install the SDD system on an existing project without touching its code. It installs a kit with 8 agents and 21 skills that works with Claude Code, Copilot and Gemini.
What it solves
When several AI agents work on the same repository, the bottleneck stops being code generation and becomes governance: specs that do not exist, code written without a decided contract, context living in someone else's head and no record of what was done and at what token cost.
Key points
Deterministic gates
Scripts, not checklists: they block writing code without a registered spec and an open cycle, and block closing a cycle without updated context or recorded token usage.
Agent pipeline
Orchestrator, functional, planner, architect, implementers and reviewer, each with its own skill.
State with strict JSON Schema
The kit ships 15 schemas and validation runs with Ajv, so project state is verifiable.
A portable kit
It is copied verbatim into any repo: the only source of project identity is sdd/global.json.
The SDD Harness gates, step by step
Features
- Deterministic gates: no spec and no cycle, no code
- Installs on existing repos without touching their code
- 10 app types, including microfrontends and Python
- Parallel sessions with file leases
- GitHub: branch and PR per cycle, kit CI
- One kit for Claude Code, Copilot and Gemini
Tech stack
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