Is the Body Composition skill free?

Yes. The skill itself is free from Jeffallan/Fitness-Tools. SkillProof publishes the install command and an independent test verdict at no cost.

What is the Body Composition SkillProof Score?

9.6/10 — installs cleanly 5/5, triggers reliably 5/5, output vs. baseline 9/10, docs & honesty 5/5.

How do I install Body Composition?

Copy the install command from this page, run it in your terminal, and restart Claude Code. Skills live in ~/.claude/skills/ (global) or .claude/skills/ inside a project.

Can I use Body Composition with Cursor, Copilot, Gemini CLI, Codex or other AI tools?

The SKILL.md format is native to Claude (Claude Code, Desktop, claude.ai). The instructions inside adapt to other assistants: Cursor rules, GitHub Copilot instructions, Windsurf rules, Custom GPTs, AGENTS.md for OpenAI Codex, and GEMINI.md for Google Gemini CLI — our conversion guides cover each, and the free converter on the tools page does the wrapping for you.

Body Composition

Computes body-fat % from skinfold calipers via Durnin-Womersley/Jackson-Pollock using a real pip library.

by Jeffallan · Jeffallan/Fitness-Tools

Tested · Works

Install — copy the command Download source ↗

Test report

Verdict: Tested · Works
Score: 9.6/10
Tested: Jul 16, 2026
Environment: Claude Code 2.x (agent harness)
Upstream re-checked: Aug 10, 2026 · 619fc10

Installed the real `fitness-tools` PyPI package (matches this same repo, v1.0.1) and ran the documented `DurninWomersley` import verbatim: for a 28-year-old male with 12/8/15/18mm skinfolds it returned density 1.05413 and Siri body fat 19.6%, which hand-checks exactly against the age-bracket coefficients in the bundled references/equations.md.

Scored on four weighted criteria — install, triggering, output vs. baseline, docs. How scoring works

Installs cleanly 5/5
Triggers reliably 5/5
Output vs. baseline 9/10
Docs & honesty 5/5

What Body Composition does

Walks through skinfold-based body composition assessment — collects age, sex, and site measurements, picks the right Durnin-Womersley or Jackson-Pollock variant, and computes body density plus body-fat % (Siri/Brozek/etc.) using the `fitness-tools` PyPI package. Triggers on skinfold, caliper, body density, or body-fat-percentage requests.

How to install Body Composition

git clone https://github.com/Jeffallan/Fitness-Tools.git
mkdir -p ~/.claude/skills
cp -r Fitness-Tools/skills/body-composition ~/.claude/skills/body-composition

Skills live in ~/.claude/skills/ (global) or .claude/skills/ (per-project). Restart Claude Code after installing.

Commands — how to trigger Body Composition

/body-composition Computes body-fat % from skinfold calipers via Durnin-Womersley/Jackson-Pollock using a real pip library.

It also activates on plain-language prompts like these:

Calculate my body fat percentage from these four skinfold measurements
What's my body density using the Jackson-Pollock caliper method?
I took skinfold measurements at the gym, can you compute my body fat?

Frequently asked questions

Is the Body Composition skill free?: Yes. The skill itself is free from Jeffallan/Fitness-Tools. SkillProof publishes the install command and an independent test verdict at no cost.
Does Body Composition work with Claude Code?: We tested it with Claude Code 2.x (agent harness) on Jul 16, 2026. Verdict: Tested · Works. Installed the real `fitness-tools` PyPI package (matches this same repo, v1.0.1) and ran the documented `DurninWomersley` import verbatim: for a 28-year-old male with 12/8/15/18mm skinfolds it returned density 1.05413 and Siri body fat 19.6%, which hand-checks exactly against the age-bracket coefficients in the bundled references/equations.md.
What is the Body Composition SkillProof Score?: 9.6/10 — installs cleanly 5/5, triggers reliably 5/5, output vs. baseline 9/10, docs & honesty 5/5.
How do I install Body Composition?: Copy the install command from this page, run it in your terminal, and restart Claude Code. Skills live in ~/.claude/skills/ (global) or .claude/skills/ inside a project.
Can I use Body Composition with Cursor, Copilot, Gemini CLI, Codex or other AI tools?: The SKILL.md format is native to Claude (Claude Code, Desktop, claude.ai). The instructions inside adapt to other assistants: Cursor rules, GitHub Copilot instructions, Windsurf rules, Custom GPTs, AGENTS.md for OpenAI Codex, and GEMINI.md for Google Gemini CLI — our conversion guides cover each, and the free converter on the tools page does the wrapping for you.