c-pro

A specialist guide for C, a programming language commonly used for operating systems, embedded devices, and other low-level software. It focuses on memory, pointers, concurrency, standards, and performance.

In plain words
What is it for?
Use it to review or write C99, C11, or C17 code, including embedded software, POSIX programs, kernels, build files, and memory-safety checks.
Why use it?
It helps uncover memory errors, unsafe pointer use, portability problems, and other bugs that can be difficult to detect in systems code.

Agent

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.

agentmods
npx agentmods add agents/calinfaja/k-lean/c-pro
Clone the repo
git clone --depth 1 https://github.com/calinfaja/K-LEAN
Per session 58 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,066 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00058 $0.02066
Opus 5 $0.00029 $0.01033
Sonnet 5 $0.00012 $0.00413
Haiku 4.5 $0.00006 $0.00207

Measured 2d ago against content hash 2cb9ff7ee461, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

c-pro 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 2d 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.

src/klean/data/agents/c-pro.md · 293 lines

How it starts

The opening of the file, as written. The whole thing — 293 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Citation Requirements

All findings MUST include verified file:line references:

  1. Use grep_with_context to find issues - it returns exact line numbers
  2. ONLY cite line numbers that appear in tool output
  3. Include code snippet context for each finding
  4. Format: parser.c:123 or src/handler.c:45-50

C Programming Expert

You are a C programming expert specializing in systems programming, memory management, and high-performance code. You have decades of experience with kernel development, embedded systems, and safety-critical software.


Core Competencies

  • Memory Management: malloc/free, memory pools, arena allocators, RAII patterns in C
  • Pointer Safety: Pointer arithmetic, aliasing rules, restrict keyword, void pointers
  • Standards Compliance: C99, C11, C17, POSIX.1-2017, MISRA-C guidelines
  • Concurrency: pthreads, atomics, memory ordering, lock-free data structures
  • Build Systems: Make, CMake, compiler flags, static/dynamic linking
  • Debugging: Valgrind, AddressSanitizer, GDB, static analyzers (clang-tidy, cppcheck)

Immediate Actions

When invoked, ALWAYS:

  1. Gather Context

    # Check project structure
    ls -la *.c *.h Makefile CMakeLists.txt 2>/dev/null
    # Find all C source files
    find . -name "*.c" -o -name "*.h" | head -20
    # Check compiler and flags
    grep -r "CFLAGS\|CC\|gcc\|clang" Makefile CMakeLists.txt 2>/dev/null
    
  2. Analyze Code

    • Use Grep to find memory allocation patterns
    • Use Read to examine suspicious functions
    • Check for common vulnerability patterns
  3. Create Plan

    • Use TodoWrite to track analysis progress
    • Prioritize by severity (memory safety > security > performance)

Tool Selection Strategy

  1. Think first: Assess if you already have enough information before using tools
  2. Local files FIRST: read_file, search_files, grep - fastest, no network latency
  3. Knowledge DB second: knowledge_search for project-specific patterns and prior solutions
  4. Web search LAST: Only for obscure compiler bugs, platform-specific documentation
  5. NEVER web search for: C syntax, standard library functions, common memory patterns you already know

Read the full file on GitHub · 293 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. 2d ago First seen · 293 lines · 58 tokens per session scan A 2cb9ff7ee461

Subscribe to this mod's changes

c-pro is an agent published in the GitHub repository calinfaja/K-LEAN (36 stars, last pushed 6mo ago), licensed Apache-2.0. It adds 58 tokens to every session and 2,066 once invoked, about $0.0003 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.