frugal-iot: Instructions file for Claude Code

CLAUDE.md

frugal-iot CLAUDE.md is an instructions file for Claude Code from mitra42/frugal-iot. It costs 16,662 tokens per session, scanned A, original, MIT.

Repository-specific instructions for the Frugal-IoT library, which runs sensor networks on affordable ESP32 and ESP8266 microcontrollers. They cover Arduino IDE and PlatformIO compatibility, examples, and generated build settings.

In plain words
What is it for?
Use them when changing the library, testing Arduino examples, configuring board partitions, or preparing a release.
Why use it?
They help keep examples working across both supported development environments and prevent manual edits to files that are generated from build settings.

Instructions file for Claude Code

Written for Claude Code: the file is CLAUDE.md.

This is mitra42/frugal-iot's own configuration. It tells Claude Code how to work on frugal-iot itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything frugal-iot configures →

Reuse

Borrowing it

Nothing to install: this file belongs to mitra42/frugal-iot. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/mitra42/frugal-iot/main/CLAUDE.md
Clone the repo
git clone --depth 1 https://github.com/mitra42/frugal-iot

Made for: Claude Code.

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 frugal-iot CLAUDE.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/mitra42/frugal-iot/claude-md.svg)](https://agentmods.dev/instructions/mitra42/frugal-iot/claude-md)
Your own site
<a href="https://agentmods.dev/instructions/mitra42/frugal-iot/claude-md"><img src="https://agentmods.dev/badge/instructions/mitra42/frugal-iot/claude-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 16,662 This file is loaded in full into every session.
When invoked 16,662 The same file — it is already loaded in full.
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 $0.16662 $0.16662
Opus 5 $0.08331 $0.08331
Sonnet 5 $0.03332 $0.03332
Haiku 4.5 $0.01666 $0.01666

Measured 8d ago against content hash 8361aeec27c9, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

frugal-iot CLAUDE.md 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.

CLAUDE.md · 1,107 lines

How it starts

The opening of the file, as written. The whole thing — 1,107 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Frugal-IoT Library

A platform for affordable, easily built sensor networks running on ESP32/ESP8266 microcontrollers. Library version: 0.1.6. MIT licence. Author: Mitra Ardron.

Wiki: https://github.com/mitra42/frugal-iot/wiki Repo: https://github.com/mitra42/frugal-iot

Compatibility

Every example .ino file must work in both:

  • Arduino IDE — open the .ino directly; dependencies installed via Library Manager
  • PlatformIO — referenced via lib_deps = Frugal-IoT@^0.1.6 in platformio.ini

Each example directory contains a platform.h file alongside the .ino. This file is auto-generated from the example's platformio.ini by running scripts/prerelease.bash (which calls scripts/generate_platform_h.py). It converts -D FLAG=value build flags into #define statements and wraps board-specific defines in #ifdef ARDUINO_BOARD_NAME guards.

  • PlatformIO reads flags directly from platformio.ini; platform.h is not used.
  • Arduino IDE picks platform.h up because _settings.h includes it when PLATFORMIO is undefined — the .ino does not need to (and on ESP8266 could not; see below).

Do not hand-edit platform.h — regenerate it by re-running scripts/prerelease.bash after changing platformio.ini.

Test-compiling an example for Arduino

scripts/arduino_compile.bash <example> <env> compiles an example exactly as the Arduino IDE would, from the command line via arduino-cli (same cores, libraries and sketchbook as the IDE — nothing needs opening). Run it from the scripts directory:

cd lib/Frugal-IoT/scripts
./arduino_compile.bash commonroom nodemcu_tambak
./arduino_compile.bash --list          # every example and its environments
./arduino_compile.bash --install-deps  # core + library.properties deps (ESP32 core is >1GB)

It passes --library .. so the working tree is compiled, not whatever stale copy sits in ~/Documents/Arduino/libraries. It regenerates platform.h first, and checks two things a bare "exit 0" would hide:

Read the full file on GitHub · 1,107 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 · 1,107 lines · 16,662 tokens per session scan A 8361aeec27c9

Subscribe to this mod's changes

frugal-iot CLAUDE.md is an instructions file published in the GitHub repository mitra42/frugal-iot (10 stars, last pushed 7d ago), licensed MIT. It adds 16,662 tokens to every session, about $0.0833 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 2026-08-31.

Related

Other instructions, from other repositories

next.js AGENTS.md

AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.

vercel/next.js · 7,296 tokens

codex AGENTS.md

AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.

openai/codex · 5,153 tokens

vscode buildNext.instructions.md

Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).

microsoft/vscode · 6,785 tokens

vscode oss-third-party-notices.instructions.md

Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, applying the notice (cutover) and fallback chain (never fail the build).

microsoft/vscode · 5,001 tokens

langchain AGENTS.md

AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.

langchain-ai/langchain · 4,469 tokens

spec-kit AGENTS.md

AGENTS.md instructions for github/spec-kit, covering agents.md, about spec kit and specify, quickstart — add a new integration in 5 steps, integration architecture and integrationmanifest — file tracking.

github/spec-kit · 7,104 tokens