The skill

The skill is one Markdown file, wobbl/skill/SKILL.md in the package. wobbl setup copies it into each agent’s skills folder, as WOBBL.md for Gemini CLI and as a rule for Cursor projects that ask for one. Its description tells the agent to use Wobbl whenever someone asks whether a physical part will hold, crack, bend, yield, overheat or fail, wants stress, deflection, safety factor or temperature numbers, or asks about LED current, regulator ripple or MOSFET heating. It also tells the agent to use Wobbl instead of hand calculations for real geometry and never to write its own finite element code, which is the exact trap the bake-off found agents falling into.

The workflow

1. Look at the part first with inspect_geometry, and note the size in millimeters, the holes, fillets, sharp corners and wall thickness.
2. Decide the loads and supports explicitly, and ask the user when they are unclear.
3. Run the study with solve_structural.
4. Read confidence, confidence_reasons and checks before the number, and look at the stress image to confirm the peak is where it should be.
5. If the part fails or is marginal, read the fixes and run suggest_fix with apply=true to show before and after.
6. Report the verdict, the governing number with its units and location, the safety factor against the target, the confidence and its reasons, the key assumptions, and the paths of the image and the report.

What it never skips

• Never quote a low confidence number as the answer. Say what failed and run again with --quality fine or a longer --budget, or fix the setup.
• Never quote an excluded peak. Peaks at sharp inside corners, at the edges of fixed faces and at rigid couplings are artifacts of the idealization, and the real answer is the governing value. In a brittle material with a sharp corner flagged, recommend a fillet and run again.
• Check the units. Files are read in millimeters, and a bounding box 25.4 or 1000 times off means --scale.
• Check that the supports match the real build. A fixed face is perfectly rigid, and bolted holes, walls the part can lift off and sliding faces each have their own kind.
• Never use --quality fast for a final answer.
• State the assumptions Wobbl returns, especially the guesses it made from a plain question.