The API and MCP in SysML v2 Projects

Scripts and AI clients work with a SysML v2 project through Holarch's API and its MCP server, with an API token from your account. They read and search the model; their changes arrive as proposals that you review and apply.

Read and search

• REST: GET /api/v1/projects/{project}/model (summary), …/elements (search by text, kind and owner, paged), …/elements/{id} (an element with its members, usages and text), …/elements/{id}/connections, …/requirements (with satisfied by and verified by), …/diagnostics and …/sysml (the SysML text of a package, by lines).
• MCP tools: model_summary, list_elements, get_element, get_connections, list_requirements, get_sysml and check_sysml. Elements are named by id or by qualified name, such as Vehicles::Car::engine.
• Replies are limited in size and paged; a reply says when something was left out.

Propose changes

• POST …/sysml/check and check_sysml check text without changing anything.
• propose_sysml proposes new text for a package; propose_element_changes proposes element edits (create, update, move, remove). Over REST: POST /api/v1/projects/{project}/proposal/changes, then POST …/proposal to send it.
• Holarch checks each proposal first. Text that does not parse, or a change that would add errors (such as unresolved names), is refused, and the reply lists the problems to fix.
• Nothing changes until someone with edit access reviews the proposal: the token's owner and the project's owners get a notification, and ✦ AI ▾ → Review “…”… opens it with the elements added, changed and removed and the text difference. Applying it is one undo step.

Systems Modeling API

• Other SysML v2 tools read the model through the read-only Systems Modeling API at /api/v1/sysml/projects: projects, one branch, its commits, and the elements and roots of a commit.
• Only the head commit holds the elements: the model as it is now. Writing through this API is not available.