Free plugin · Claude Code
MBSE Requirements, as a Claude Code skill
One command and your agent stops writing requirements that read well and fail review. The five EARS patterns, permanent ID schemes, a banned-word list, and a repair workflow that shows you the diff rather than rewriting your specification behind your back.
Free and stays free · No account · Nothing to run
Install
Two commands, inside Claude Code
These are typed at the Claude Code prompt, not in your shell. A marketplace in Claude Code is simply a Git repository it reads a manifest from, so the first command points it at ours and the second installs from it.
1. Add the marketplace
/plugin marketplace add radsilent/mbe3d-skills
Claude Code fetches the repository and reports the marketplace name it found,
vector-stream-systems, along with the plugins in it.
2. Install the skill
/plugin install mbse-requirements@vector-stream-systems
Claude Code shows you what the plugin contains before it enables anything. This one is a single skill: no commands, no hooks, no MCP servers, and no executables. Confirm, and it is available in your next message.
3. Use it
There is nothing to invoke. The skill declares what it is for, and your agent reaches for it when
the work matches: writing a shall statement, reviewing a specification, assigning
requirement IDs, splitting a compound requirement. Ask for something like:
Review the requirements in docs/srs.md and tell me which ones would fail a design review, and why.
Browsing rather than installing? /plugin on its own opens the plugin manager, where
added marketplaces and their plugins are listed and can be enabled or disabled.
What it knows
The part a general model was never taught
Ask any assistant for requirements and what comes back is compound shall statements,
performance claims with no units or measurement conditions, and design decisions dressed up as
requirements. It reads well enough to circulate, and you find out in review.
- The five EARS patterns, and which one a given requirement actually wants. Ubiquitous, event-driven, state-driven, unwanted-behaviour and optional each have a shape, and picking the wrong one is how a requirement becomes untestable.
- Permanent ID schemes that survive renumbering, so a trace matrix written today still resolves after the document is reorganised.
- A banned-word list that rejects “robust”, “user-friendly” and the rest on sight, with the reason attached rather than a bare complaint.
- A repair workflow that shows the diff. An agent that silently rewrites your specification has replaced a review you were going to do with one you now cannot.
What is free, and what is not
This is one skill. There are ten.
Requirements authoring is free: the whole skill, not a trimmed sample, and it stays that way. The other nine are the paid pack, they are not in the public repository, and they are licensed separately. Installing this one does not get you those.
| Skill | What it does | Included |
|---|---|---|
mbse-requirements | EARS authoring, review and repair | Free |
mbse-safety-analysis | MIL-STD-882E severity, probability and RAC; FHA and FMEA | Pack |
mbse-traceability | Audit queries and change-impact analysis | Pack |
mbse-verification | Method selection, pass criteria, evidence schema | Pack |
mbse-model-format | A portable, diffable model file and its validator | Pack |
mbe3d-connect | Connecting to MBE3Dstudio, and its failure modes | Pack |
mbe3d-load | Getting a model in with its attributes intact | Pack |
mbe3d-analyze | SPARQL, competency suites and CI gates | Pack |
mbe3d-studio | The 3D surface and the provenance model under it | Pack |
mbe3d-harness | The agent runtime, its plugins and its session log | Pack |
Five work on your own files. Four connect to MBE3Dstudio, which is licensed separately.
Licence
Free to use. Not free to repackage.
Use it on any number of machines, for your own work and for client work you do yourself, and modify it for your own use. What is not permitted is reselling it, sublicensing it, or republishing it as part of another product, template, course or skill pack. The paid eight are under a separate licence that does not permit publication at all.
Questions, or a site licence for your team: get in touch.