A focused Model Context Protocol provider for SysON and SysML v2. An MCP client works with a real SysON model through explicit modelling, navigation, diagram, requirement, constraint and value operations, and shows the results in interactive MCP Apps.
Every result comes with a compact MCP App that does one job, so a host can compose them without embedding a modelling tool. The diagram viewer draws SysON's General, Interconnection, Action Flow and State Transition views with SysON's notation, in SysON's layout or an automatic one.
diagram-viewer — a State Transition view: nested states, entry actions, triggers and guards |
diagram-viewer — an Interconnection view: parts, ports, connections and item flows |
model-explorer-viewer — the model as a tree, loaded branch by branch, with filters by kind |
query-results-viewer — AQL and search results, filtered and sorted |
requirements-viewer — authored requirements and their limits |
requirements-trace-viewer — satisfaction and verification coverage, gaps included |
validation-viewer — constraints evaluated against the model's values, with margins |
value-change-viewer — a value before and after its change, with its read-back |
Click an element to add it to the AI context of the next turn; double-click or press Enter to open it. See Browse model elements and diagram views.
The images are rendered by deno task docs:viewer-screenshot from recorded
sessions and tool results (docs/fixtures, tests/fixtures/live-audit). The
same operations work in clients without MCP Apps, and no tool calls a language
model: interpretation, approval and orchestration stay with the calling client.
You need Deno 2.x and a SysON instance. The included development stack starts a reviewed SysON image and PostgreSQL locally:
docker compose up -d
export SYSON_URL=http://localhost:8180Run the published package over HTTP:
deno run -A jsr:@casys/mcp-syson@0.9.2/serverThe MCP endpoint is http://127.0.0.1:3009/mcp. For a client that launches one local process, use stdio instead:
deno run -A jsr:@casys/mcp-syson@0.9.2/server --stdioAn existing SysON deployment works too; point SYSON_URL at its base URL. The
server never guesses an endpoint.
See Getting started for Docker, transport, category, authentication and renderer configuration.
- Create projects, documents, packages and explicit SysML v2 structures.
- Browse and query model elements while preserving SysON identifiers.
- Draw SysON diagrams with their notation, in SysON's layout or an automatic one; a local SVG (or an opt-in external renderer) serves clients without MCP Apps.
- Trace requirements and derive product structures from model evidence.
- Evaluate unit-aware constraints and explore bounded what-if values.
- Update model values and perform fail-closed destructive operations.
The provider does not turn an acknowledgement into proof. Critical writes need read-back, unresolved values stay unresolved, and permanent deletion is only reported after its postcondition is observed. The exact safety and evidence semantics live in Capabilities, safety and evidence.
- Getting started and configuration
- Capabilities, safety and evidence
- Browse model elements and diagram views
- MCP Apps and recorded viewer contracts
- Provider APIs, architecture and development
- Release history
- Private vulnerability reporting
deno task check
deno task lint
deno task fmt
deno task testViewer development uses the published MCP View packages and requires a rebuild after source changes. The complete loop is documented in MCP Apps and recorded viewer contracts.