mechanical-design-mentor

Mechanical Design Mentor — a Claude Code skill

A Claude Code skill that turns Claude into a senior mechanical-engineering design mentor. Keep Claude open in a sidebar while you model in Onshape (or SolidWorks / Fusion 360), paste a screenshot when you get stuck, and Claude reviews it over your shoulder — diagnosing the issue, teaching the why, and handing you one concrete next step.

It is built for learning to think like a mechanical engineer, not for generating model files. Ask things like:

• "What am I doing wrong with this sketch?" (paste a screenshot)
• "How should I approach this part?"
• "Is this a good way to constrain / mate this?"
• "How would a real mechanical engineer think about this?"
• "How do I detail this drawing for the machine shop?"
• "Translate this SolidWorks tutorial into Onshape steps."

How it works

The skill runs a tight mentoring loop on every question:

READ the screenshot → DIAGNOSE the upstream-most cause → TEACH the one principle that matters → give ONE next action → (optionally) a Socratic question that makes you reason.

It deliberately doesn't redesign your part for you. The goal is to build your judgment so the next hundred parts come out better.

Installation

This repo is a Claude Code plugin marketplace. From inside Claude Code:

/plugin marketplace add jakedahn/mechanical-design-mentor
/plugin install mechanical-design-mentor@jakedahn

Then start a fresh session. The skill auto-triggers on CAD/engineering questions, or run it explicitly with /mechanical-design-mentor.

Prefer not to use the plugin system? Drop the skill straight into your skills folder instead:

cp -r plugins/mechanical-design-mentor/skills/mechanical-design-mentor ~/.claude/skills/

Usage

Once installed, the skill activates in two ways inside Claude Code:

• Auto-trigger. Ask a CAD/engineering question or paste a screenshot of your Onshape session ("why is my sketch still blue?", "how should I mate this hinge?") and Claude picks up the skill from its trigger keywords (Onshape, SolidWorks, sketch, mate, tolerance, GD&T, drawing, DFM, and so on).
• Explicit slash command. Type /mechanical-design-mentor to invoke it directly.

The sidebar-plus-screenshot workflow is the intended way to use it: model in your browser, screenshot, ask, learn.

What's inside

The skill uses progressive disclosure — SKILL.md is always loaded and routes to a deep reference only when a question needs it.

File	Purpose
SKILL.md	The mentor persona, the mentoring loop, the universal screenshot/DOF literacy, and a router to the references
references/parametric-modeling.md	Sketching, constraints, degrees of freedom, the feature tree, design intent, variables
references/feature-modeling.md	Extrude/revolve/sweep/loft, booleans, patterns, fillet-vs-chamfer order, shell/rib/draft, the hole tool
references/assemblies-and-motion.md	Assemblies, mates/joints, grounding, in-context design, and mechanisms & kinematics
references/tolerances-fits-and-gdt.md	Limits & fits (ISO 286), IT grades, tolerance stack-ups, and GD&T
references/engineering-drawings.md	Views, projection angle, dimensioning, surface finish, title block / BOM, weld symbols
references/materials.md	Material families, properties, the Ashby selection method, fatigue/creep, cost
references/manufacturing-and-dfm.md	Manufacturing process survey and DFM/DFA design rules
references/fastening-and-joining.md	Threaded fasteners plus welds, adhesives, press fits, and snap fits
references/machine-elements.md	Gears, bearings, shafts, couplings, belts/chains, springs
references/mechanics-and-strength.md	Stress, factor of safety, beam bending, stress concentration, buckling, fatigue, FEA sanity
references/onshape-and-tools.md	Onshape platform deep-dive and cross-CAD translation (SolidWorks/Fusion)
references/mentoring-and-screenshot-reading.md	Deep screenshot diagnosis, level calibration, a Socratic question bank, practice exercises

Repository layout

.claude-plugin/marketplace.json              # marketplace definition
plugins/mechanical-design-mentor/
  .claude-plugin/plugin.json                 # plugin manifest
  skills/mechanical-design-mentor/
    SKILL.md                                 # the skill entry point
    references/*.md                          # the 12 reference docs

Scope

This skill teaches mechanical-engineering and CAD thinking and helps you work in real tools and reason about drawings, tolerances, materials, and manufacturing. It does not generate model files, geometry, or CAD scripts — if you want to generate geometry, that's a job for a different tool. Here, you keep the pen.

License

Licensed under the MIT License.