SysML v2 interoperability

GDS can project a specification into a SysML v2 architecture view for inspection by engineering tools. The experimental gds_interchange.sysml exporter produces text and a mapping/loss manifest. The thermostat export has passed the official Pilot validator; OpenSysML and repository-backed exchange remain untested.

The exporter remains unmerged development work. The downloadable artifacts and validation evidence below are available for inspection, but generation requires a development checkout containing the exporter. It is not part of the published symbolic security releases.

What is available

spec_to_sysml accepts a flat registry of atomic blocks and explicit wire mappings. It exports parts, forward ports, scalar payload definitions, and forward connections. Its result contains text and manifest_json().

Keep the .sysml file and manifest together. The manifest records source URI, source revision, mapping version, source-to-target entries, and diagnostics for omitted semantics. Third-party tools do not automatically interpret this GDS-specific manifest.

The thermostat example includes downloadable artifacts and a generation command. Its four parts and three forward connections were accepted by the official Pilot on 2026-09-25, with zero errors and zero diagnostics. The validation evidence records the versions, hashes, logs, and negative controls.

How the tools fit together

Tool or repository	Role alongside GDS	Integration status
GDS / gds-interchange	Generate a structural view and preserve mapping provenance	Experimental exporter exists
Official SysML v2 Pilot	Parse, resolve references, and validate SysML against matching libraries	Thermostat accepted by a pinned version
OpenSysML	An additional language implementation with validation, model inspection, execution, and client APIs	Candidate consumer; GDS compatibility untested
Flexo / MMS	Store engineering models in repositories with projects, branches, and revisions	Proposed GDS exchange target
SysML v2 Web Modeler	Edit and render models through a SysML v2 API-backed service	Proposed consumer; GDS exchange untested
Eclipse SysON	An alternative SysML v2 modeling environment	Import/export capabilities must be checked for a chosen release

OpenSysML provides a Go implementation, language server, REPL, runtime, and programmatic clients. Its execution support creates overlap with GDS analysis, but equivalent results require explicit behavioral mappings and tests. Acceptance by the Pilot does not establish acceptance by OpenSysML.

SysML v2 Web Modeler provides text editing and model rendering against a repository API. Eclipse SysON provides web-based modeling. They are possible ways to inspect or edit an exchanged architecture; neither has been tested with this GDS export.

A possible workflow is:

flowchart LR
    G["GDS specification"] --> E["SysML text + mapping manifest"]
    E --> P["Pilot validation: thermostat tested"]
    E -.-> O["OpenSysML validation and inspection: proposed"]
    P -.-> R["Versioned model repository: proposed"]
    O -.-> R
    R -.-> V["Engineering editor and views: proposed"]

Dashed connections describe proposed integrations. The manifest must remain associated with the source snapshot even when a repository stores the SysML elements separately from the original text.

Boundaries that matter

• Behavior: forward connectivity does not specify scheduling or state updates. Backward feedback and temporal wiring are omitted with diagnostics. GDS roles and execution contracts are not executable SysML behavior.
• Types: built-in scalar payloads are supported. Units, constraints, custom payload types, and IEEE floating-point semantics are not preserved by this projection.
• Composition: only flat atomic-block registries are accepted. Hierarchical composition and reusable definition/usage mappings need further design.
• Identity: generated identifiers are snapshot-local. They are not stable repository element identities, so edits cannot yet be reliably synchronized.
• Direction: there is no SysML importer, round-trip editing, API synchronization, or demonstrated simulation equivalence.

OpenSysML documents repository comparison and synchronization through its CLI. These operate on element identities; transport support alone does not solve GDS identity or semantic mapping. The SysML v2 API reference implementation is a separate integration boundary from the textual language.

Next acceptance gates

1. Pin an OpenSysML version and its compatible libraries. Load the unchanged thermostat and both negative-control files; retain diagnostics and hashes.
2. Inspect the four parts and all three connection endpoint pairs. Compare them with the GDS manifest and the recorded Pilot result.
3. Test a repository import on a separate branch, preserving source text, manifest, source revision, and validation evidence. Check identity and revision behavior before attempting synchronization.
4. Define a selected reverse mapping only after structural exchange works. Executable analysis additionally requires explicit units, time contracts, supported functions, and behavior-equivalence tests.

The comparison study explains the underlying mapping choices. Use the existing OWL bridge when RDF, SHACL, or SPARQL is the required interface; RDF output by itself does not establish SysML v2 API compatibility.