c

c is a skill for Claude Code, Codex from G1Joshi/Agent-Skills. It costs 23 tokens per session (291 once invoked), scanned A, original, MIT.

A general-purpose programming language that gives direct access to memory through pointers and manual allocation. It is widely used for software close to the operating system or hardware.

In plain words
What is it for?
Use it for operating systems, device drivers, embedded systems, high-performance software, and existing C codebases.
Why use it?
It offers predictable control over memory and execution, but requires the programmer to prevent leaks, invalid memory use, and buffer overflows.

Skill for Claude CodeCodex

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

Good fit Use it for operating systems, device drivers, embedded systems, high-performance software, and existing C codebases.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/g1joshi/agent-skills/c
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 G1Joshi/Agent-Skills --skill c
Clone the repo
git clone --depth 1 https://github.com/G1Joshi/Agent-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 c

README.md
[![agentmods](https://agentmods.dev/badge/skills/g1joshi/agent-skills/c/github.svg)](https://agentmods.dev/skills/g1joshi/agent-skills/c)
Your own site
<a href="https://agentmods.dev/skills/g1joshi/agent-skills/c"><img src="https://agentmods.dev/badge/skills/g1joshi/agent-skills/c/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 c

Your own site · 80×15
<a href="https://agentmods.dev/skills/g1joshi/agent-skills/c"><img src="https://agentmods.dev/badge/skills/g1joshi/agent-skills/c.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 23 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 291 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 $0.00023 $0.00291
Opus 5 $0.00012 $0.00146
Sonnet 5 $0.00005 $0.00058
Haiku 4.5 $0.00002 $0.00029

Measured 5d ago against content hash 2f3f9ddf7329, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

c 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 5d 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/languages/c/SKILL.md · 71 lines

What it actually says

C

The foundational language for modern computing, operating systems, and embedded systems.

When to Use

  • Operating Systems / Drivers
  • Embedded Systems
  • High-performance computing
  • Legacy codebases

Quick Start

#include <stdio.h>

int main() {
    printf("Hello, World!\n");
    return 0;
}

Core Concepts

Pointers

Variables that store memory addresses.

int x = 10;
int *p = &x; // p holds address of x
printf("%d", *p); // Dereference p to get 10

Memory Management

Manual allocation and deallocation.

int *arr = (int*)malloc(10 * sizeof(int));
// use arr...
free(arr);

Structs

User-defined data types.

Best Practices

Do:

  • Always initialized variables
  • Check return values of malloc
  • Guard against buffer overflows (use snprintf over sprintf)
  • Use tools like Valgrind to check for leaks

Don't:

  • Return pointers to local variables (stack memory)
  • Use gets() (unsafe)

References

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. 5d ago First seen · 71 lines · 23 tokens per session scan A 2f3f9ddf7329

Subscribe to this mod's changes

c is a skill published in the GitHub repository G1Joshi/Agent-Skills (12 stars, last pushed 7mo ago), licensed MIT. It adds 23 tokens to every session and 291 once invoked, about $0.0001 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 2026-09-03.

Related

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