circuit-simulator

circuit-simulator is a skill for Claude Code, Codex from captainluzik/oh-my-embedded. It costs 37 tokens per session (1,646 once invoked), scanned A, original, MIT.

A workflow for simulating electronic circuits with ngspice, a program that predicts circuit behavior from a circuit description. It supports analog and mixed-signal analysis.

In plain words
What is it for?
Use it to create or modify circuit netlists, run transient or other simulations, inspect voltage and current results, and analyze impedance or filtering.
Why use it?
It lets you test power supplies, filters, matching networks, and sensor interfaces before building hardware, and compare results while iterating on the design.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to create or modify circuit netlists, run transient or other simulations, inspect voltage and current results, and analyze impedance or filtering.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/captainluzik/oh-my-embedded/circuit-simulator
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 captainluzik/oh-my-embedded --skill circuit-simulator
Clone the repo
git clone --depth 1 https://github.com/captainluzik/oh-my-embedded

Made for: Claude Code, Codex.

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 circuit-simulator

README.md
[![agentmods](https://agentmods.dev/badge/skills/captainluzik/oh-my-embedded/circuit-simulator.svg)](https://agentmods.dev/skills/captainluzik/oh-my-embedded/circuit-simulator)
Your own site
<a href="https://agentmods.dev/skills/captainluzik/oh-my-embedded/circuit-simulator"><img src="https://agentmods.dev/badge/skills/captainluzik/oh-my-embedded/circuit-simulator.svg" alt="Measured on agentmods" height="20"></a>
Per session 37 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,646 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.
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 $0.00037 $0.01646
Opus 5 $0.00018 $0.00823
Sonnet 5 $0.00007 $0.00329
Haiku 4.5 $0.00004 $0.00165

Measured 8d ago against content hash dabc4114726d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

circuit-simulator 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.

skills/circuit-simulator/SKILL.md · 185 lines

How it starts

The opening of the file, as written. The whole thing — 185 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Circuit Simulation Engineer

You are a circuit simulation engineer using ngspice for analog and mixed-signal analysis. You design and verify power supplies, filters, matching networks, and sensor interfaces. You use the Spicebridge MCP for direct ngspice interaction.

ngspice Workflow

  1. Define circuit (netlist) -> 2. Set analysis type -> 3. Run simulation -> 4. Extract results -> 5. Iterate on design

Netlist Format

* Title line (first line is always title)
* Component: Name Node+ Node- Value

R1 in mid 10k
R2 mid gnd 10k
C1 mid gnd 100n
V1 in gnd DC 3.3

.control
tran 1u 10m
plot v(mid)
.endc

.end

Component Syntax

  • Resistor: R<name> <n+> <n-> <value> (1k, 10k, 1Meg)
  • Capacitor: C<name> <n+> <n-> <value> (1p, 100n, 10u)
  • Inductor: L<name> <n+> <n-> <value> (10n, 1u, 100u)
  • Voltage source: V<name> <n+> <n-> DC <val> or AC <val>
  • Current source: I<name> <n+> <n-> DC <val>
  • Diode: D<name> <anode> <cathode> <model>
  • MOSFET: M<name> <drain> <gate> <source> <body> <model> W=<w> L=<l>
  • Op-amp (behavioral): E<name> <out+> <out-> <in+> <in-> <gain>

Node Naming

  • 0 or gnd: ground reference (always required)
  • Named nodes: in, out, vdd, mid (no spaces, case-insensitive)

Analysis Types

DC Operating Point

.op

Shows all node voltages and branch currents. Use first to verify bias points.

DC Sweep

.dc V1 0 5 0.01

Sweep V1 from 0 to 5V in 10mV steps. Useful for: transfer functions, I-V curves, regulator output vs input.

AC Analysis (Frequency Response)

.ac dec 100 1 100Meg

100 points per decade, 1Hz to 100MHz. Source must have AC component:

V1 in gnd DC 1.65 AC 1

Plot magnitude: plot vdb(out) (dB), phase: plot vp(out) (degrees).

Transient Analysis

.tran 1u 10m

Time step 1us, stop time 10ms. For power supply startup, step response, oscillation. Pulse source for step response:

V1 in gnd PULSE(0 3.3 1m 10n 10n 5m 10m)
* PULSE(V1 V2 Tdelay Trise Tfall Twidth Tperiod)

Read the full file on GitHub · 185 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 · 185 lines · 37 tokens per session scan A dabc4114726d

Subscribe to this mod's changes

circuit-simulator is a skill published in the GitHub repository captainluzik/oh-my-embedded (24 stars, last pushed 6mo ago), licensed MIT. It adds 37 tokens to every session and 1,646 once invoked, about $0.0002 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 2026-08-30.

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