Agent skill

Create Validation

by ghbalf in ghbalf/freecad-ai

Generate a draft VALIDATION.md for a skill by analyzing its SKILL.md construction steps

LGPL-2.1Auto-check passed

Install Create Validation

skills CLI
$ npx skills add ghbalf/freecad-ai --skill create-validation -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install ghbalf/freecad-ai create-validation --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/ghbalf/freecad-ai.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/create-validation .claude/skills/create-validation && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
create-validation
GitHub stars
548
Token cost
~1.2k tokens
SKILL.md length
556 words
Files
1
Skills in repo
9
Repo updated
First seen
Licence
LGPL-2.1

At a glance

Generate a draft VALIDATION.md for a skill by analyzing its SKILL.md construction steps

  • Works in 5 steps: Review every check — does it match what… → Verify all volume formulas by hand —… → Test with --validate — run the skill… → …
  • SKILL.md covers WARNING — READ THIS FIRST, How to use, What to do and Rules for generating volume…, plus 2 more sections
  • Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Create Validation is an agent skill from ghbalf/freecad-ai. Generate a draft VALIDATION.md for a skill by analyzing its SKILL.md construction steps

Its SKILL.md is about 1.2k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

The repository describes itself as: AI-powered assistant workbench for FreeCAD — generate 3D models from natural language.

Example prompts

  • “/create-validation”

Requirements

  • Python 3

Workflow steps

5 steps, taken from the first numbered list in SKILL.md.

  1. Review every check — does it match what the skill actually builds?
  2. Verify all volume formulas by hand — volume calculations for complex geometry (shells with posts, lips, ridges) are easy to get wrong…
  3. Test with --validate — run the skill with known-good parameters and --validate to see if the checks pass on correct geometry.
  4. Adjust tolerances — the defaults (0.5mm for bbox, 5% for volume) may be too tight or too loose for your skill.
  5. Check conditional rules — if your skill has variants, verify each when block covers the right checks.

What it can do on your machine

Read from SKILL.md and the folder at commit 5ef1e2d. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    No scripts in the folder and no shell commands in SKILL.md (its code samples are python and markdown).

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Create Validation loads about 1.2k tokens when it runs. Until then it costs about 26 tokens; SKILL.md has 556 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~26
When it runs · the whole SKILL.md, loaded when a task matches
~1.2k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from ghbalf/freecad-ai at commit 5ef1e2d, republished under its LGPL-2.1 licence (© ghbalf). 556 words, ~1,249 tokens.

Download SKILL.mdSave it as .claude/skills/create-validation/SKILL.md (or your agent's skills folder).
name
create-validation
description
Generate a draft VALIDATION.md for a skill by analyzing its SKILL.md construction steps

Create Validation Rules

Generate a draft VALIDATION.md file for a skill by analyzing its SKILL.md.

WARNING — READ THIS FIRST

This skill generates a DRAFT, not a finished product. The generated VALIDATION.md will likely contain errors, especially in volume formulas. You MUST:

  1. Review every check — does it match what the skill actually builds?
  2. Verify all volume formulas by hand — volume calculations for complex geometry (shells with posts, lips, ridges) are easy to get wrong. Calculate the expected volume for one set of dimensions and compare with the formula.
  3. Test with --validate — run the skill with known-good parameters and --validate to see if the checks pass on correct geometry.
  4. Adjust tolerances — the defaults (0.5mm for bbox, 5% for volume) may be too tight or too loose for your skill.
  5. Check conditional rules — if your skill has variants, verify each when block covers the right checks.

Common errors in generated VALIDATION.md:

  • Volume formulas that forget to add/subtract features (posts, holes, lips, ridges)
  • Wrong body labels (FreeCAD may rename bodies)
  • Missing conditional branches for skill variants
  • Tolerances that are too tight for the geometry complexity

How to use

/create-validation skill-name

Where skill-name is the name of an existing skill (e.g., enclosure, gear).

What to do

  1. Read the specified skill's SKILL.md using execute_code:

    python
    import os
    skills_dirs = [
        os.path.expanduser("~/.config/FreeCAD/FreeCADAI/skills"),
    ]
    # Also check built-in skills
    builtin = os.path.join(os.path.dirname(os.path.dirname(os.path.abspath(__file__))), "skills") if '__file__' in dir() else ""

    Or use get_document_state context to find the skill path.

  2. Analyze the SKILL.md to extract:

    • Parameters: from the "Parameters to extract" section. Note types and defaults.
    • Bodies: from create_body instructions. Note their labels.
    • Geometry steps: pad dimensions, pocket depths, post positions, etc.
    • Variants: different lid types, optional features, conditional construction steps.
  3. Generate VALIDATION.md with this structure:

markdown
# Validation Rules

## Parameters
(one line per parameter: name: type = default)

## Checks

### Body count
- total_bodies: N

### BodyLabel
- exists: true
- bbox: X_expr, Y_expr, Z_expr (tolerance 0.5)
- volume: formula (tolerance 5%)
- solid_count: 1
- valid_solid: true

#### when variant_param == "value"
- (variant-specific checks)
  1. Write the file to the skill directory as VALIDATION.md.

  2. IMPORTANT: After writing, display this message to the user:

Draft VALIDATION.md created. This is a starting point, NOT a finished file.

You must verify:

  • All volume formulas — calculate expected values by hand for at least one set of dimensions
  • Body labels match what FreeCAD actually creates (use get_document_state after running the skill)
  • Conditional when blocks cover all variants
  • Tolerances are appropriate (0.5mm bbox, 5% volume are defaults)

Test it: Run /skill-name args --validate to check against actual geometry.

Fix it: Edit the VALIDATION.md directly if checks fail on correct geometry.

Show full SKILL.md (186 more words)Show less

Rules for generating volume formulas

  • Rectangular shell (box with hollow interior): L*W*H - (L-2*T)*(W-2*T)*(H-T)
    • This gives 4 walls + floor, open top
  • Cylindrical posts added to interior: + N * pi * R**2 * post_height
    • N = number of posts, R = post radius
  • Cylindrical holes subtracted: - N * pi * R**2 * depth
  • Solid slab (lid): L * W * T
  • Lid with lip: lip volume + slab volume
  • Use pi constant, not 3.14159 (the expression evaluator supports pi)
  • Use ** for power, not ^ (the evaluator uses Python's ast module)

Available check types

CheckValue formatWhen to use
exists: true—Always, for each body
bbox: X, Y, Z (tolerance 0.5)Expressions, absolute mmAlways, for each body
volume: expr (tolerance 5%)Expression, relative %When geometry has calculable volume
solid_count: NIntegerAlways (usually 1 per body)
valid_solid: true—Always, for each body
total_bodies: NIntegerOnce, at document level
has_holes: NIntegerWhen through-all pockets expected
has_feature: "Name"StringWhen specific named features expected
min_children: NIntegerWhen minimum feature count matters

Parameter type reference

TypeDefault syntaxExample
float= 2.5T: float = 2
int= 4count: int = 4
str= valuelid_type: str = screw
bool= falseadd_vents: bool = false

© ghbalf, LGPL-2.1. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

Just SKILL.md in skills/create-validation of ghbalf/freecad-ai.

Open the folder on GitHubat commit 5ef1e2d

Compare with similar skills

Create Validation next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Create Validation compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Create Validation this skillghbalf/freecad-ai548—~1.2kAutomated safety check: PassLGPL-2.1
Agent Code Analyzerruvnet/ruflo74k3 repos~1.5kAutomated safety check: PassMIT
Agent Pagerank Analyzerruvnet/ruflo74k3 repos~2.9kAutomated safety check: PassMIT
Agent Performance Analyzerruvnet/ruflo74k2 repos~1.3kAutomated safety check: PassMIT
Diff Analyzeruvnet/ruflo74k—~450Automated safety check: NotesMIT
Agent Analyze Code Qualityruvnet/ruflo74k2 repos~1.2kAutomated safety check: PassMIT

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Questions about Create Validation

What does Create Validation do?

Generate a draft VALIDATION.md for a skill by analyzing its SKILL.md construction steps. Create Validation is an agent skill from ghbalf/freecad-ai.

How do I install Create Validation in Claude Code?

Run `npx skills add ghbalf/freecad-ai --skill create-validation -a claude-code`. Or copy the skill folder (skills/create-validation in ghbalf/freecad-ai) into .claude/skills/create-validation in your project. Claude Code loads it when a task matches its description.

How do I install Create Validation in Codex?

Run `npx skills add ghbalf/freecad-ai --skill create-validation -a codex`. Or copy the skill folder (skills/create-validation in ghbalf/freecad-ai) into .agents/skills/create-validation in your project. Codex loads it when a task matches its description.

Can I use Create Validation in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add ghbalf/freecad-ai --skill create-validation -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/create-validation, .gemini/skills/create-validation, .github/skills/create-validation and .opencode/skills/create-validation in your project.

What does Create Validation need to run?

SKILL.md names no scripts, command-line tools or credentials: Create Validation is instructions for the agent only. Our summary lists: Python 3.

Does Create Validation access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Create Validation safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Create Validation use?

Create Validation is published under the LGPL-2.1 licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Create Validation use?

About 1.2k tokens (SKILL.md is roughly 5k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Create Validation?

Skills that share tags, products or a category with Create Validation: Agent Code Analyzer (ruvnet/ruflo, 74k stars), Agent Pagerank Analyzer (ruvnet/ruflo, 74k stars), Agent Performance Analyzer (ruvnet/ruflo, 74k stars) and Diff Analyze (ruvnet/ruflo, 74k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Create Validation?

ghbalf (a GitHub user) maintains it in ghbalf/freecad-ai, which has 548 GitHub stars. The repository holds 9 skills in this directory. The repository was last updated on October 3, 2026.

Source: ghbalf/freecad-ai on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.