zephyr-i2c

zephyr-i2c is a skill for Claude Code, Codex from ksachdeva/zephyr-rtos-ai. It costs 183 tokens per session (3,773 once invoked), scanned A, original, Apache-2.0.

Expert instructions for using I2C, a short-distance bus that lets a microcontroller communicate with sensors and other chips, in Zephyr OS.

In plain words
What is it for?
Use it to configure I2C through devicetree or Kconfig, read and write device registers, perform transfers, handle callbacks, or make a device act as an I2C target.
Why use it?
It helps choose and configure the right communication method for blocking transfers, asynchronous work, real-time I/O, or peripheral mode.

Skill for Claude CodeCodex

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

Good fit Use it to configure I2C through devicetree or Kconfig, read and write device registers, perform transfers, handle callbacks, or make a device act as an I2C target.

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Install with agentmods
npx agentmods add skills/ksachdeva/zephyr-rtos-ai/zephyr-i2c
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 ksachdeva/zephyr-rtos-ai --skill zephyr-i2c
Clone the repo
git clone --depth 1 https://github.com/ksachdeva/zephyr-rtos-ai

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 zephyr-i2c

README.md
[![agentmods](https://agentmods.dev/badge/skills/ksachdeva/zephyr-rtos-ai/zephyr-i2c/github.svg)](https://agentmods.dev/skills/ksachdeva/zephyr-rtos-ai/zephyr-i2c)
Your own site
<a href="https://agentmods.dev/skills/ksachdeva/zephyr-rtos-ai/zephyr-i2c"><img src="https://agentmods.dev/badge/skills/ksachdeva/zephyr-rtos-ai/zephyr-i2c/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 zephyr-i2c

Your own site · 80×15
<a href="https://agentmods.dev/skills/ksachdeva/zephyr-rtos-ai/zephyr-i2c"><img src="https://agentmods.dev/badge/skills/ksachdeva/zephyr-rtos-ai/zephyr-i2c.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 183 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,773 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 $0.00183 $0.03773
Opus 5 $0.00092 $0.01886
Sonnet 5 $0.00037 $0.00755
Haiku 4.5 $0.00018 $0.00377

Measured 10d ago against content hash 5c6cf4adc564, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

zephyr-i2c 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 10d 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/zephyr-i2c/SKILL.md · 504 lines

How it starts

The opening of the file, as written. The whole thing — 504 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Zephyr I2C

Expert guidance for Zephyr's I2C driver subsystem covering synchronous and asynchronous transfer APIs, target/slave mode, devicetree configuration, and common usage patterns.

Table of Contents

  1. API Selection
  2. Getting Device Reference
  3. Common Workflows
  4. Configuration
  5. Target Mode
  6. Error Handling
  7. Troubleshooting

API Selection

Zephyr provides multiple I2C access methods. Choose based on requirements:

API Kconfig Use Case Blocking?
Synchronous (default) Simple transfers, blocking until complete Yes
Async Callback CONFIG_I2C_CALLBACK Non-blocking with completion callback No
RTIO CONFIG_I2C_RTIO Real-time I/O subsystem integration No
Target Mode CONFIG_I2C_TARGET Act as I2C peripheral/slave device N/A

Decision Tree

Simple blocking transfer? -> Synchronous (i2c_transfer, i2c_write_read)
Register read/write? -> Helpers (i2c_reg_read_byte, i2c_reg_write_byte)
Need non-blocking? -> Async callback (i2c_transfer_cb)
RTIO integration? -> RTIO API (i2c_rtio_copy)
Respond to controller? -> Target mode (i2c_target_register)
SMBus protocol? -> SMBus API (smbus_byte_data_read, etc.)

Getting Device Reference

From Devicetree (Preferred - for I2C Devices)

Use I2C_DT_SPEC_GET to get a complete I2C specification including bus and address:

#include <zephyr/device.h>
#include <zephyr/drivers/i2c.h>

/* Define the I2C device from devicetree */
#define MY_I2C_DEVICE DT_NODELABEL(my_sensor)

static const struct i2c_dt_spec i2c_dev = I2C_DT_SPEC_GET(MY_I2C_DEVICE);

/* Runtime check (in main or init) */
if (!i2c_is_ready_dt(&i2c_dev)) {
    printk("I2C device not ready\n");
    return -ENODEV;
}

Direct Controller Access

/* Get I2C controller directly */
const struct device *i2c = DEVICE_DT_GET(DT_NODELABEL(i2c0));

if (!device_is_ready(i2c)) {
    return -ENODEV;
}

/* Use with explicit address */
#define SENSOR_ADDR 0x48
ret = i2c_read(i2c, buf, sizeof(buf), SENSOR_ADDR);

Read the full file on GitHub · 504 lines

Files

What ships with it

3 files 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.

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. 10d ago First seen · 504 lines · 183 tokens per session scan A 5c6cf4adc564

Subscribe to this mod's changes

zephyr-i2c is a skill published in the GitHub repository ksachdeva/zephyr-rtos-ai (23 stars, last pushed 3mo ago), licensed Apache-2.0. It adds 183 tokens to every session and 3,773 once invoked, about $0.0009 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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