Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add kouya-group/fcgen-mcp --skill skillgit clone --depth 1 https://github.com/kouya-group/fcgen-mcpWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/kouya-group/fcgen-mcp/skill)<a href="https://agentmods.dev/skills/kouya-group/fcgen-mcp/skill"><img src="https://agentmods.dev/badge/skills/kouya-group/fcgen-mcp/skill/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/kouya-group/fcgen-mcp/skill"><img src="https://agentmods.dev/badge/skills/kouya-group/fcgen-mcp/skill.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00146 | $0.02142 |
| Opus 5.5 | $0.00058 | $0.00857 |
| Sonnet 5.5 | $0.00029 | $0.00428 |
| Haiku 4.5 | $0.00015 | $0.00214 |
Grade A, and why
fcgen scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 216 lines — stays where its author put it; the contents beside it link to each section on GitHub.
fcgen -- Parametric CAD Generation via MCP
Generate verified parametric CAD parts (STEP/STL) through the fcgen MCP server and FreeCAD.
Critical Rules
- ALWAYS call
find_templatefirst to resolve constraints and presets - NEVER change canonical parameter values without explicit user confirmation
- NEVER skip
validate_paramsbeforegenerate_partorgenerate_assembly - If
validate_paramsreturns warnings, inform the user before proceeding - ALL dimensions are in millimeters (mm)
- Each part
idin an assembly MUST be unique - Only verified templates can be used for generation
Documentation
This skill uses the project's docs/ as its single source of truth. Read these files for detailed reference:
docs/mcp-tools.md-- Full MCP tools reference (parameters, return values, examples)docs/assembly-guide.md-- Assembly spec format, placement rules, examplesdocs/template-guide.md-- Custom template creation guidedocs/quickstart.md-- Quick start guide and available templates
Available MCP Tools
| Tool | Purpose |
|---|---|
check_freecad |
Verify FreeCAD is installed and compatible |
list_templates |
List all verified templates |
get_template_schema |
Get full JSON Schema for a template |
get_template_example |
Get working example parameters |
get_template_constraints |
Get canonical/variant/linked/configurable constraints |
validate_params |
Dry-run validation with canonical deviation warnings |
find_template |
Search by name, purpose, tags, or presets (e.g. "M5 bolt 20mm") |
generate_part |
Generate single part (STEP/STL) |
generate_assembly |
Generate multi-part assembly with interference check |
list_candidates |
List unverified candidate templates |
propose_template |
Register new template as candidate |
verify_template |
Verify and promote candidate to verified |
Workflow: Generate a Single Part
Step 1: Find template with constraints
Call find_template(purpose) with the user's description. This searches templates, constraints, and presets. Example queries: "M5 bolt 20mm", "soccer ball", "LEGO 2x4".
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 2mo ago First seen · 216 lines · 146 tokens per session scan A ac3075c2217d
fcgen is a skill published in the GitHub repository kouya-group/fcgen-mcp (1 stars, last pushed 4mo ago), licensed MIT. It adds 146 tokens to every session and 2,142 once invoked, about $0.0006 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
fcgen compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| fcgenkouya-group/fcgen-mcp | Skill | 1 | 4mo ago | MIT | A | 146 | Claude Code, Codex |
| solidworks-vibecadwzyn20051216/solidworks-automation-skill | Skill | 1.8k | 3d ago | MIT | A | 96 | Claude Code, Codex |
| bdf_font_converterespressif/esp-claw | Skill | 2.4k | 5d ago | Apache-2.0 | A | 27 | Claude Code, Codex |
| fluidcad-assemblyFluid-CAD/FluidCAD | Skill | 693 | yesterday | MIT | A | 154 | Claude Code, Codex |
| gen-assemblypartcad/partcad | Skill | 515 | yesterday | Apache-2.0 | A | 111 | Claude Code |
| gen-partpartcad/partcad | Skill | 515 | yesterday | Apache-2.0 | A | 114 | Claude Code |
| gen-sketchpartcad/partcad | Skill | 515 | yesterday | Apache-2.0 | A | 201 | Claude Code |