Troubleshooting COMSOL through sim-cli

COMSOL not detected

Symptom. sim check comsol reports the solver as missing or unreachable; sim connect --solver comsol fails immediately.
Diagnostic. uv run sim plugin doctor comsol --deep.
Likely fix. Confirm a licensed COMSOL Multiphysics install is on the host, and that the comsol launcher is on PATH or pointed at by the documented environment variable for your install layout.

Symptom. sim connect opens then immediately exits with a license-server error in the log; sim check comsol may pass because the binary is found but a license seat is not.
Diagnostic. Run COMSOL once outside sim-cli to confirm interactive licensing works, then uv run sim plugin doctor comsol --deep.
Likely fix. Check FlexLM / network-license configuration with your IT team; sim-cli does not proxy license traffic, so anything that breaks comsol standalone will also break the sim-cli session.

Symptom. Agent runs through sim-cli succeed but you see no COMSOL Desktop window, or the engineer’s GUI window does not reflect the agent’s actions.
Diagnostic. uv run sim inspect session.health while the session is open.
Likely fix. Reconnect with the shared-desktop visual mode for your workflow; headless and shared-desktop are distinct session types and cannot be converted mid-session.

Symptom. Agent reports changes to the model but a re-inspection shows the old state, or two parallel sessions disagree about parameters.
Diagnostic. uv run sim inspect session.summary and confirm the reported .mph path is the file the agent thinks it edited.
Likely fix. Close stray sessions, reopen against the canonical .mph path, and save a checkpoint immediately after the next successful step so the agent has a known-good anchor.

Symptom. Agent invents method or property names that don’t exist in the COMSOL Java/Python API; sim exec fails with attribute errors.
Diagnostic. Re-read the bundled sim-comsol skill in .agents/skills/sim-comsol/ (or .claude/skills/sim-comsol/).
Likely fix. Re-prompt the agent with: “Do not guess COMSOL API names. Inspect the model first, then use only names returned by the inspection.” If the skill is missing, re-run uv run sim plugin sync-skills --target .agents/skills --copy.