analyze-magnetic-field

analyze-magnetic-field is a skill for Claude Code from pjt222/agent-almanac. It costs 79 tokens per session (3,689 once invoked), scanned A, original, MIT.

A physics workflow for calculating magnetic fields produced by electric currents and magnetic materials. It chooses between standard laws such as Biot–Savart and Ampère’s law based on the source geometry and symmetry.

In plain words
What is it for?
Use it to analyse wires, coils, helices, irregular conductors, multiple sources, magnetic materials, and far-field dipole approximations.
Why use it?
It helps turn a current arrangement into field values and visual field lines while checking approximations and limiting cases. This avoids choosing an unsuitable calculation method for the geometry.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Part of the agent-almanac plugin — 122 skills, 76 agents shipped together

Good fit Use it to analyse wires, coils, helices, irregular conductors, multiple sources, magnetic materials, and far-field dipole approximations.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/pjt222/agent-almanac/analyze-magnetic-field
Install

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.

Any agent
npx skills add pjt222/agent-almanac --skill analyze-magnetic-field
Clone the repo
git clone --depth 1 https://github.com/pjt222/agent-almanac

Made for: Claude Code.

Or install agent-almanac, the plugin that ships this one along with the rest of its 122 skills, 76 agents.

Wrote 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.

agentmods badge for analyze-magnetic-field

README.md
[![agentmods](https://agentmods.dev/badge/skills/pjt222/agent-almanac/analyze-magnetic-field/github.svg)](https://agentmods.dev/skills/pjt222/agent-almanac/analyze-magnetic-field)
Your own site
<a href="https://agentmods.dev/skills/pjt222/agent-almanac/analyze-magnetic-field"><img src="https://agentmods.dev/badge/skills/pjt222/agent-almanac/analyze-magnetic-field/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.

agentmods 80×15 button for analyze-magnetic-field

Your own site · 80×15
<a href="https://agentmods.dev/skills/pjt222/agent-almanac/analyze-magnetic-field"><img src="https://agentmods.dev/badge/skills/pjt222/agent-almanac/analyze-magnetic-field.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 79 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,689 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Memory Poisoning · line 101
    Skill manipulates agent memory, state, or stored context. Memory corruption can alter personality, override safety rules, or cause unpredictable behavior.
    Fix: Protect agent memory and state from modification by untrusted content. Use read-only memory for critical instructions and validate all state changes.
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00079 $0.03689
Opus 5 $0.00039 $0.01844
Sonnet 5 $0.00016 $0.00738
Haiku 4.5 $0.00008 $0.00369

Measured 8d ago against content hash e98aa7a8c0dc, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

analyze-magnetic-field 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 8d 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.

i18n/caveman-lite/skills/analyze-magnetic-field/SKILL.md · 239 lines

How it starts

The opening of the file, as written. The whole thing — 239 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Analyze Magnetic Field

Calculate the magnetic field produced by a given current distribution by characterizing the source geometry, selecting the appropriate law (Biot-Savart for arbitrary geometries, Ampere's law for high-symmetry configurations), evaluating field integrals, checking limiting cases, incorporating magnetic material effects where relevant, and visualizing the resulting field-line topology.

When to Use

  • Computing the B-field from an arbitrary current-carrying conductor (wire loop, helix, irregular path)
  • Exploiting cylindrical, planar, or toroidal symmetry to apply Ampere's law directly
  • Estimating far-field behavior via the magnetic dipole approximation
  • Superposing fields from multiple current sources
  • Analyzing magnetic materials: linear permeability, B-H curves, hysteresis, saturation

Inputs

  • Required: Current distribution specification (geometry, current magnitude and direction)
  • Required: Region of interest where the field is needed (observation points or volume)
  • Optional: Material properties (relative permeability, B-H curve data, coercivity, remanence)
  • Optional: Desired accuracy level (exact integral, multipole expansion order, numerical resolution)
  • Optional: Visualization requirements (2D cross-section, 3D field lines, magnitude contour map)

Procedure

Step 1: Characterize Current Distribution and Geometry

Fully specify the source before selecting a method:

  1. Current path: Describe the geometry of every current-carrying element. For line currents, specify the path as a parametric curve r'(t). For surface currents, specify the surface current density K (A/m). For volume currents, specify J (A/m^2).
  2. Coordinate system: Choose coordinates aligned with the dominant symmetry. Cylindrical (rho, phi, z) for wires and solenoids. Spherical (r, theta, phi) for dipoles and loops at large distances. Cartesian for planar sheets.
  3. Symmetry analysis: Identify translational, rotational, and reflection symmetries. A symmetry of the source is a symmetry of the field. Document which components of B are nonzero by symmetry and which vanish.
  4. Current continuity: Verify that the current distribution satisfies div(J) = 0 (steady state) or div(J) = -d(rho)/dt (time-varying). Inconsistent current distributions produce unphysical fields.

Read the full file on GitHub · 239 lines

Changes

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.

  1. 8d ago First seen · 239 lines · 79 tokens per session scan A e98aa7a8c0dc

Subscribe to this mod's changes

analyze-magnetic-field is a skill published in the GitHub repository pjt222/agent-almanac (33 stars, last pushed yesterday), licensed MIT. It adds 79 tokens to every session and 3,689 once invoked, about $0.0004 per session on Opus 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 2026-09-03.

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