fatfs-integration

fatfs-integration is a skill for Claude Code, Codex from easyzoom/aix-skills. It costs 42 tokens per session (785 once invoked), scanned A, original, MIT.

An integration guide for FatFs, a portable C library that reads and writes FAT-family filesystems. These filesystems are commonly used on SD cards, USB storage, and embedded flash devices.

In plain words
What is it for?
Use it when adding or debugging file storage on SD cards, eMMC, USB storage, RAM disks, or SPI flash, including long filenames, Unicode, and exFAT.
Why use it?
It helps distinguish filesystem problems from errors in the underlying disk or sector driver. It also guides checks for mounting, file access, media timing, and filesystem settings.

Skill for Claude CodeCodex

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

Good fit Use it when adding or debugging file storage on SD cards, eMMC, USB storage, RAM disks, or SPI flash, including long filenames, Unicode, and exFAT.

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Install with agentmods
npx agentmods add skills/easyzoom/aix-skills/fatfs-integration
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 easyzoom/aix-skills --skill fatfs-integration
Clone the repo
git clone --depth 1 https://github.com/easyzoom/aix-skills

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 fatfs-integration

README.md
[![agentmods](https://agentmods.dev/badge/skills/easyzoom/aix-skills/fatfs-integration/github.svg)](https://agentmods.dev/skills/easyzoom/aix-skills/fatfs-integration)
Your own site
<a href="https://agentmods.dev/skills/easyzoom/aix-skills/fatfs-integration"><img src="https://agentmods.dev/badge/skills/easyzoom/aix-skills/fatfs-integration/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 fatfs-integration

Your own site · 80×15
<a href="https://agentmods.dev/skills/easyzoom/aix-skills/fatfs-integration"><img src="https://agentmods.dev/badge/skills/easyzoom/aix-skills/fatfs-integration.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 42 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 785 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 $0.00042 $0.00785
Opus 5 $0.00021 $0.00392
Sonnet 5 $0.00008 $0.00157
Haiku 4.5 $0.00004 $0.00078

Measured 10d ago against content hash 48d9228312cb, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

fatfs-integration 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/fatfs-integration/SKILL.md · 85 lines

How it starts

The opening of the file, as written. The whole thing — 85 lines — stays where its author put it; the contents beside it link to each section on GitHub.

FatFs Integration

Overview

Use this skill to integrate FatFs by proving the disk I/O layer before trusting filesystem behavior. FatFs is portable C, but the target-specific diskio functions, sector geometry, mount policy, and media timing decide whether it works reliably.

When To Use

Use this skill when:

  • The user wants to add or debug FatFs on SD card, eMMC, USB MSC, RAM disk, SPI flash, or block devices.
  • The issue involves f_mount, f_open, f_read, f_write, FR_DISK_ERR, FR_NOT_READY, FR_NO_FILESYSTEM, long filenames, Unicode, or exFAT.
  • The project uses ff.c, ffconf.h, diskio.c, or FATFS.

Do not use this skill when the raw block device cannot read/write sectors yet; debug the storage driver first.

First Questions

Ask for:

  • Media type and transport: SDIO, SPI SD, eMMC, USB MSC, RAM disk, or flash translation layer.
  • Sector size, sector count, erase/block size, and whether writes are cached.
  • ffconf.h, diskio.c, and current FatFs return code.
  • RTOS or bare-metal runtime and whether reentrancy is enabled.
  • Whether formatting is allowed. Formatting can destroy user data.
  • Long filename, Unicode, exFAT, timestamp, and multi-volume requirements.

Integration Checklist

  1. Prove disk I/O. disk_initialize, disk_status, disk_read, disk_write, and disk_ioctl must work independently.

  2. Match sector geometry. FatFs expects logical sectors and correct sector count. GET_SECTOR_COUNT, GET_SECTOR_SIZE, and CTRL_SYNC matter.

  3. Mount before formatting. Try f_mount first. Ask before f_mkfs or any operation that can erase media.

  4. Configure ffconf.h intentionally. Reentrancy, LFN buffers, exFAT, code page, relative paths, and timestamp support affect RAM and behavior.

  5. Add locking if shared. Enable and implement synchronization when multiple tasks can access the same volume.

  6. Verify persistence. Write, f_sync/f_close, unmount/reset, remount, and read back.

Common Failures

Read the full file on GitHub · 85 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. 10d ago First seen · 85 lines · 42 tokens per session scan A 48d9228312cb

Subscribe to this mod's changes

fatfs-integration is a skill published in the GitHub repository easyzoom/aix-skills (31 stars, last pushed 1mo ago), licensed MIT. It adds 42 tokens to every session and 785 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.