This matrix compares the four spec-driven development tools profiled in this section, feature by feature. Everything below was re-verified against live sources on 2026-09-13.
The category splits on two axes: who owns the specs (your repo or a platform) and whether the ceremony sizes itself to the change, and the waterfall critique is the standing judge of the second axis.
Legend: ✓ supported, ✗ not supported, ~ partial or conditional, ? not verified as of the date above. Each column links to the full research note; every cell below traces to a source cited there or in the references.
The matrix #
| Feature | BMad Method | GitHub Spec Kit | OpenSpec | Tessl |
|---|---|---|---|---|
| Kind | method plus agent workflows, npm install | Python CLI plus slash-command templates | spec toolkit CLI, npm install | hosted platform, thin CLI |
| Steward | BMad Code, LLC | GitHub | Fission AI | Tessl (Podjarny), $125M raised |
| License | ✓ MIT | ✓ MIT | ✓ MIT | ✗ closed platform |
| Artifact model | briefs, specs, architecture carried forward | constitution, spec, plan, tasks files | delta proposals archived into a living ledger | specs live on the platform |
| Workflow entry | bmad-build with right-sized depth |
/speckit-constitution then specify |
/opsx:propose then apply and archive |
web workflow |
| Ceremony sizing | ✓ right-sizes to the change | ✗ fixed ceremony | ~ fixed but light | ? not verified |
| Brownfield support | ✓ establish-context path | ~ not the primary case | ✓ explicit design goal | ? not verified |
| Convergence checking | ✓ verify and learn loop | ✓ converge step | ~ archive keeps ledger current | ? not verified |
| Unattended execution | ✓ BMad Loop module | ✗ | ✗ | ? not verified |
| Adoption | about 53k stars | about 136k stars | about 68k stars, 1.8M npm downloads a month | 24-point raise thread, thin OSS surface |
| Pricing | free | free | free | free tier plus Team at $100 per month, Enterprise custom |
Reading the matrix #
The license and steward rows tell the ownership story: three repo-native MIT toolkits against one closed, funded platform, and the free tools set the price anchor at zero while Tessl spends $125M betting specs are rentable. The adoption row inverts the funding row, which is the tension to watch.
Ceremony sizing is the design axis the waterfall critique created: only BMad sends small changes straight to build, and the two artifact-first tools pay for their simplicity with fixed ceremony. If your changes are mostly small, that row alone picks your column.
Brownfield is the sleeper row: OpenSpec is explicitly built for existing code, BMad has an establish-context path, and spec-kit’s scaffolding still assumes a fresher repo than most of us have.
Choosing from the matrix #
- Existing codebase, want the spec ledger to stay current: OpenSpec.
- Want a whole delivery process with roles and retrospectives: BMad Method.
- Heterogeneous org, zero cost, constitution ceremony acceptable: Spec Kit.
- Want specs as a managed product and accept portability questions: Tessl.
Changes #
- 2026-08-27 - Created as a single-column Spec Kit scaffold.
- 2026-08-27 - Rebuilt to four columns (BMad, OpenSpec, Spec Kit, Tessl) across the ownership and ceremony-sizing axes.
See also #
- Task Management Feature Matrix - the boards these specs eventually fill
- Kiro - the spec-first IDE, the closed alternative on the editor axis
- AGENTS.md - the lighter convention all of these extend
- Send Implementation, Not Issue - the corpus argument for specs plus implementation
References #
https://github.com/bmad-code-org/BMAD-METHOD - loop, modules, licensing for the BMad column
https://martinfowler.com/articles/exploring-gen-ai/sdd-3-tools.html - the third-party analysis covering Kiro, Spec Kit, and Tessl
https://www.tessl.io/blog/announcing-our-series-a-for-ai-native-software-development - the raise grounding the Tessl column
https://api.npmjs.org/downloads/point/last-month/@fission-ai/openspec - the OpenSpec install velocity