· EasySpecs
Understanding OpenSpec: Spec-Driven Development explained
What OpenSpec is, how its SDD workflow works, who it is for—and how it relates to Spec Review on EasySpecs.
Guide to the OpenSpec Spec-Driven Development framework.
OpenSpec is one of the tools teams evaluate when they move from vibe coding to Spec-Driven Development (SDD)—putting a specification at the center of how AI coding agents work.
A brownfield-first SDD framework that isolates changes with delta specs and an archive merge into a living source of truth.
Who builds it
Fission AI · MIT (open source)
What it is good at
- Designed for existing codebases (1→n), not only blank repos
- Delta markers (ADDED / MODIFIED / REMOVED) keep change intent explicit
- Lightweight Propose → Apply → Archive state machine
- Agent-agnostic slash-command style integration
How the workflow usually runs
- Propose a change folder with proposal, tasks, and delta specs
- Validate structure and iterate until the change is agreed
- Apply: agents implement against the agreed deltas
- Archive: merge into canonical specs and keep history
Best fit
Teams iterating on established systems who want low-overhead SDD without a heavy constitution ceremony.
Limitations to know
Structure validation is not the same as behavioural Specs Readiness; drift still needs human discipline. No multi-persona Document Review of what the system already does.
How this relates to EasySpecs
SDD frameworks like OpenSpec help agents and engineers structure how work gets specified and implemented.
EasySpecs is the Spec Review Platform: Document Review of what the code already does, Spec Review before the next change, and Specs Readiness so Product, POs, and Engineering share one grounded story—not only a CLI workflow in the agent.
Use OpenSpec when you need that framework’s SDD loop. Use EasySpecs when the bottleneck is trusting and reviewing specs across the team.
Next steps