spice

spice is a skill for Claude Code from aklofas/kicad-happy. It costs 177 tokens per session (5,363 once invoked), scanned B, original, MIT.

An electronics simulation workflow that creates and runs SPICE test circuits for subcircuits found in a KiCad schematic. SPICE is software that predicts circuit behavior; supported simulators include ngspice, LTspice, and Xyce.

In plain words
What is it for?
Use it to check filter frequencies, voltage-divider ratios, op-amp gains, LC resonance, and crystal load capacitance from analyzed schematics.
Why use it?
It removes much of the manual work of creating simulation inputs and setting up analyses. It compares calculated circuit values with simulated results and reports warnings or failures.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the kicad-happy plugin — 11 skills shipped together

Good fit Use it to check filter frequencies, voltage-divider ratios, op-amp gains, LC resonance, and crystal load capacitance from analyzed schematics.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/aklofas/kicad-happy/spice
About the project

kicad-happy is a collection of coding-agent skills and tools that inspect KiCad schematics, PCB layouts, and Gerber files for electronics design issues. It is for hardware designers who want automated reviews, simulations, datasheet checks, component sourcing, and fabrication preparation. The catalogue entries are its agent skills, rules, plugin, and instruction for integrating this workflow with coding agents.

aklofas/kicad-happy · 1,175 stars · on GitHub

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 aklofas/kicad-happy --skill spice
Clone the repo
git clone --depth 1 https://github.com/aklofas/kicad-happy

Made for: Claude Code.

Or install kicad-happy, the plugin that ships this one along with the rest of its 11 skills.

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 spice

README.md
[![agentmods](https://agentmods.dev/badge/skills/aklofas/kicad-happy/spice/github.svg)](https://agentmods.dev/skills/aklofas/kicad-happy/spice)
Your own site
<a href="https://agentmods.dev/skills/aklofas/kicad-happy/spice"><img src="https://agentmods.dev/badge/skills/aklofas/kicad-happy/spice/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 spice

Your own site · 80×15
<a href="https://agentmods.dev/skills/aklofas/kicad-happy/spice"><img src="https://agentmods.dev/badge/skills/aklofas/kicad-happy/spice.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 177 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,363 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • Socket pass 17 Apr 2026
  • Snyk warn 17 Apr 2026
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 2 findings, up to medium

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 →

  • medium analysis-evasion · line 1
    Suspicious Unicode normalization or mixed-script content
    Fix: Review the flagged content for security risks. Ensure no credentials, secrets, or sensitive data are exposed.
  • medium Privilege Escalation · line 39
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
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 $0.00177 $0.05363
Opus 5 $0.00088 $0.02681
Sonnet 5 $0.00035 $0.01073
Haiku 4.5 $0.00018 $0.00536

Measured 11d ago against content hash 297526a5459b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade B, and why

spice scanned grade B with 1 finding 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 11d ago.

The scan reads SKILL.md. This mod also ships 11 executable files (scripts/extract_parasitics.py, scripts/simulate_subcircuits.py, scripts/spice_model_cache.py, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Asks for rootmediumPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

- **ngspice** — `sudo apt install ngspice` (Linux) / `brew install ngspice` (macOS) / ngspice.sourceforge.io (Windows). Most common choice.
skills/spice/SKILL.md · 334 lines

How it starts

The opening of the file, as written. The whole thing — 334 lines — stays where its author put it; the contents beside it link to each section on GitHub.

SPICE Simulation Skill

Automatically generates and runs SPICE testbenches for circuit subcircuits detected by the kicad skill's schematic analyzer. Supports ngspice, LTspice, and Xyce (auto-detected). Validates calculated values (filter frequencies, divider ratios, opamp gains) against actual simulation results and produces a structured report.

This skill inverts the typical simulation workflow: instead of requiring users to create simulation sources and configure analysis (which ~2.5% of KiCad users do), it generates targeted testbenches automatically from the analyzer's subcircuit detections.

Skill Purpose
kicad Schematic/PCB analysis — produces the analyzer JSON this skill consumes
digikey Parametric specs for behavioral models, datasheet downloads
mouser Parametric specs (secondary source), datasheet downloads
lcsc Parametric specs (no auth needed), datasheet downloads
element14 Parametric specs (international), datasheet downloads
emc EMC pre-compliance — uses this skill's simulator infrastructure for SPICE-enhanced PDN impedance and EMI filter analysis

Handoff guidance: The kicad skill's analyze_schematic.py produces the analysis JSON with subcircuit detections in the flat findings[] array (filtered by detector field). This skill reads that JSON, generates SPICE testbenches for simulatable subcircuits, runs the detected simulator (ngspice/LTspice/Xyce), and produces a structured verification report. Always run the schematic analyzer first. During a design review, run simulation after the analyzer and before writing the final report — simulation results should appear as a verification section in the report. The emc skill reuses this skill's simulator backend for SPICE-enhanced PDN impedance and EMI filter insertion loss checks — when ngspice is available, the EMC skill's --spice-enhanced flag activates these checks automatically.

Requirements

Read the full file on GitHub · 334 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. 11d ago First seen · 334 lines · 177 tokens per session scan B 297526a5459b

Subscribe to this mod's changes

spice is a skill published in the GitHub repository aklofas/kicad-happy (1,175 stars, last pushed 9d ago), licensed MIT. It adds 177 tokens to every session and 5,363 once invoked, about $0.0009 per session on Opus 5. A static security scan graded it B with 1 finding (asks for root). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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