| name | cayenne-modeler |
| description | Use this skill when the user explicitly wants to open CayenneModeler (the GUI) on a Cayenne project, or when the modeling task is inherently visual — reverse engineering (delegated to cayenne-reverse-engineer), bulk relationship layout, multi-entity visual refactoring. Trigger on phrases like 'open the Modeler', 'open in CayenneModeler', 'launch the GUI', 'edit visually', 'show me the project in the Modeler'. Do NOT trigger as a fallback for ordinary a-la-carte XML edits — those belong in the cayenne-modeling skill, which is faster and doesn't require the user to context-switch. |
cayenne-modeler
Launch CayenneModeler with a Cayenne project file pre-loaded, via the mcp__cayenne__open_project MCP tool.
Required reading
${CLAUDE_PLUGIN_ROOT}/references/mcp-tools.md — open_project tool reference and failure modes.${CLAUDE_PLUGIN_ROOT}/references/project-layout.md — locate the project descriptor.
Step 1 — Resolve the project path
The MCP tool needs an absolute path to a top-level project descriptor (cayenne-*.xml). Use project-layout.md to find it. If multiple descriptors exist, ask which one. Cache for the rest of the session.
If no descriptor exists yet, the user is starting from scratch. Two options:
- Create a minimal descriptor first (use
cayenne-modeling to scaffold it), then open.
- Open the Modeler on any path it'll accept and use File → New Project inside.
For starting fresh, option 2 is simpler — but open_project does require an existing readable file.
Step 2 — Call open_project
mcp__cayenne__open_project({ "projectPath": "<absolute path to cayenne-*.xml>" })
If the tool is not available (MCP server not registered), surface cayenne-mcp-server/README.md and stop. Do not attempt to launch CayenneModeler by any other means — the bundled launcher relies on the MCP server's discovery of the Modeler installation.
The tool spawns the Modeler asynchronously, then waits up to ~15 seconds for a startup handshake. Possible return codes:
| Code | Meaning |
|---|
ok | Modeler launched and loaded the project. |
modeler_not_found | The MCP jar is not co-located with a Modeler installation. User needs to install CayenneModeler properly. |
project_not_found | The projectPath doesn't exist or isn't readable. |
handshake_timeout | The Modeler started but didn't confirm load within the timeout. Often this means it's still loading — the user can check the GUI directly. |
launch_failed | Process spawn failed. Surface the error message. |
Step 3 — Hand off to the user
Once open_project returns ok, the user is in the GUI. From here, depending on intent:
- Reverse engineering: that's the
cayenne-reverse-engineer skill's job to walk them through. Do not duplicate that workflow here — just open and step out.
- Visual layout / bulk editing: tell the user what tab to navigate to (e.g., DataMap → ObjEntity for entity-level edits, DataMap → Class Generation for cgen config) and let them work. Don't try to script GUI actions.
- Just wanted to see the project: nothing more to do.
When NOT to use this skill
- A-la-carte XML edits. Adding one entity, tweaking one attribute, renaming a relationship — all faster as direct XML edits via
cayenne-modeling. Don't context-switch the user to the GUI for trivial work.
- Class generation. That's
cayenne-cgen's job, fully scripted via MCP. No GUI needed.
Anti-patterns
- Do not trigger as a generic fallback for "Cayenne tasks." This skill is for explicit user requests or inherently visual workflows. The
cayenne-modeling skill handles most modeling intent.
- Do not retry
open_project on handshake_timeout — the Modeler may still be loading. Tell the user to check the GUI window directly.
- Do not attempt to launch CayenneModeler outside the MCP tool (no
java -jar direct calls, no opening a .dmg, no open -a CayenneModeler). The MCP tool's launcher knows where the installation lives.
