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 hamzabellouch/agent-skills --skill orbital-motion-kepler-s-lawsgit clone --depth 1 https://github.com/hamzabellouch/agent-skillsWrote 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/hamzabellouch/agent-skills/orbital-motion-kepler-s-laws)<a href="https://agentmods.dev/skills/hamzabellouch/agent-skills/orbital-motion-kepler-s-laws"><img src="https://agentmods.dev/badge/skills/hamzabellouch/agent-skills/orbital-motion-kepler-s-laws/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/hamzabellouch/agent-skills/orbital-motion-kepler-s-laws"><img src="https://agentmods.dev/badge/skills/hamzabellouch/agent-skills/orbital-motion-kepler-s-laws.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 | $0.00040 | $0.00372 |
| Opus 5.5 | $0.00016 | $0.00149 |
| Sonnet 5.5 | $0.00008 | $0.00074 |
| Haiku 4.5 | $0.00004 | $0.00037 |
Grade A, and why
orbital-motion-kepler-s-laws 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 7d 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.
What it actually says
Orbital Motion and Kepler's Laws
ID: mech.gravitation.orbits_kepler
Domain: Mechanics → Gravitation
Difficulty: 4/5
Prerequisites
- mech.gravitation.field_potential
- mech.rotation.ang_momentum_conservation
Core Concepts
- Kepler's laws
- circular orbit
- elliptical orbit
- vis-viva equation
- orbital energy
Key Equations
$$ T^2 \propto a^3 $$ $$ \frac{dA}{dt} = \text{const} $$ $$ E = -\frac{GMm}{2a} $$ $$ v^2 = GM\left(\frac{2}{r}-\frac{1}{a}\right) $$
Methods
- Use vis-viva for speed at any radius
- Use energy and angular momentum conservation
- Apply Kepler's third law for periods
Typical Problem Types
- Circular orbit speed
- Elliptical orbit energy
- Satellite transfer orbits
Common Pitfalls
- Assuming circular when the orbit is elliptical
- Forgetting that a is the semi-major axis
Related Skills
- mech.gravitation.escape_velocity
- rel.general.schwarzschild
References
- Kleppner & Kolenkow Ch.9
- Taylor Ch.8
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 7d ago First seen · 63 lines · 40 tokens per session scan A 909cd352ae13
orbital-motion-kepler-s-laws is a skill published in the GitHub repository hamzabellouch/agent-skills (8 stars, last pushed today), licensed MIT. It adds 40 tokens to every session and 372 once invoked, about $0.0002 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 2026-10-10.
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