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 elastic-collisionsgit 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/elastic-collisions)<a href="https://agentmods.dev/skills/hamzabellouch/agent-skills/elastic-collisions"><img src="https://agentmods.dev/badge/skills/hamzabellouch/agent-skills/elastic-collisions/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/elastic-collisions"><img src="https://agentmods.dev/badge/skills/hamzabellouch/agent-skills/elastic-collisions.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 | $0.00030 | $0.00313 |
| Opus 5.5 | $0.00012 | $0.00125 |
| Sonnet 5.5 | $0.00006 | $0.00063 |
| Haiku 4.5 | $0.00003 | $0.00031 |
Grade A, and why
elastic-collisions 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
Elastic Collisions
ID: mech.momentum.elastic
Domain: Mechanics → Momentum
Difficulty: 3/5
Prerequisites
- mech.momentum.conservation
- mech.energy.conservation
Core Concepts
- elastic collision
- coefficient of restitution
- equal-mass exchange
- CM frame
Key Equations
$$ e = \frac{v_2'-v_1'}{v_1-v_2} = 1 $$ $$ v_1' = \frac{m_1-m_2}{m_1+m_2}v_1 $$
Methods
- Use momentum conservation plus KE conservation
- Work in the CM frame for simplicity
- Solve the coupled equations
Typical Problem Types
- 1D elastic collision
- Equal masses exchanging velocities
- 2D elastic scattering
Common Pitfalls
- Using KE conservation for inelastic collisions
- Wrong sign of relative velocity
Related Skills
- mech.momentum.inelastic
- mech.momentum.center_of_mass
References
- Taylor Ch.3
- Kleppner & Kolenkow Ch.4
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 · 56 lines · 30 tokens per session scan A 2e416745a117
elastic-collisions is a skill published in the GitHub repository hamzabellouch/agent-skills (8 stars, last pushed today), licensed MIT. It adds 30 tokens to every session and 313 once invoked, about $0.0001 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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