clean-code-c

clean-code-c is a skill for Claude Code from CassetteTapeCrackle/claude-starters. It costs 34 tokens per session (318 once invoked), scanned A, original, MIT.

A set of deeper C coding and review rules for memory ownership, safe strings, allocation checks, initialization, and file visibility. It builds on C11, CMake, clang-tidy, sanitizers, and unit-test tools.

In plain words
What is it for?
Use it when writing or reviewing C code, especially code that allocates memory, handles strings, manages resources, or exposes functions and variables across files.
Why use it?
It helps prevent memory leaks, use-after-free errors, buffer overflows, uninitialized reads, and unclear ownership in C code.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the claude-starters plugin — 9 skills, 1 command, 8 agents, 2 hooks shipped together

Good fit Use it when writing or reviewing C code, especially code that allocates memory, handles strings, manages resources, or exposes functions and variables across files.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/cassettetapecrackle/claude-starters/clean-code-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 CassetteTapeCrackle/claude-starters --skill clean-code-c
Clone the repo
git clone --depth 1 https://github.com/CassetteTapeCrackle/claude-starters

Made for: Claude Code.

Or install claude-starters, the plugin that ships this one along with the rest of its 9 skills, 1 command, 8 agents, 2 hooks.

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 clean-code-c

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/cassettetapecrackle/claude-starters/clean-code-c"><img src="https://agentmods.dev/badge/skills/cassettetapecrackle/claude-starters/clean-code-c.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 34 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 318 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 $0.00034 $0.00318
Opus 5 $0.00017 $0.00159
Sonnet 5 $0.00007 $0.00064
Haiku 4.5 $0.00003 $0.00032

Measured 8d ago against content hash 78a93d00121f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

clean-code-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 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.

skills/clean-code-c/SKILL.md · 27 lines

What it actually says

Clean-code C (depth)

On top of the base rules (C11, CMake, clang-tidy, ASan+UBSan, Unity/CMocka).

Memory & ownership

  • Document ownership at every allocating function: who frees, when. One owner; transfer explicitly.
  • Check every malloc/realloc/calloc return. Free on every path (goto-cleanup pattern for multi-resource functions).
  • Set freed pointers to NULL if reused. Never return pointers to stack locals.

Safety

  • No VLAs; no unbounded strcpy/strcat/sprintf — use snprintf and bounded copies with explicit sizes.
  • sizeof(*ptr) (variable) over sizeof(Type) so it survives type changes. Initialize every variable at declaration.

Structure

  • static for internal-linkage functions/globals; expose the minimum in headers.
  • const-correct parameters; size_t for sizes/indices. Small functions; early returns; one responsibility per file.

Smells

  • An allocation whose free path isn't obvious → add the ownership comment or restructure with goto-cleanup.
  • sprintf/strcpy into a fixed buffer → bounded call.
  • Uninitialized variable read (UBSan will catch it) → initialize at declaration.
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 · 27 lines · 34 tokens per session scan A 78a93d00121f

Subscribe to this mod's changes

clean-code-c is a skill published in the GitHub repository CassetteTapeCrackle/claude-starters (1 stars, last pushed 20d ago), licensed MIT. It adds 34 tokens to every session and 318 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 2026-08-31.

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