coding-guidance-cpp

Coding and review guidance for modern C++ programs, focusing on ownership, type safety, public interfaces, and tests.

In plain words
What is it for?
Use it for portable C++ implementation, refactoring, optimization, and review across common build systems, or use the Qt guide when Qt behavior is central.
Why use it?
It helps prevent memory-lifetime, API-design, and unsafe-type problems in C++17, C++20, and C++23 code.

Skill for Claude CodeCodex

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 skills/n-n-code/n-n-code-skills/coding-guidance-cpp
Any agent
npx skills add n-n-code/n-n-code-skills --skill coding-guidance-cpp
Clone the repo
git clone --depth 1 https://github.com/n-n-code/n-n-code-skills

Made for: Claude Code, Codex.

Per session 72 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,242 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 $0.00072 $0.02242
Opus 5 $0.00036 $0.01121
Sonnet 5 $0.00014 $0.00448
Haiku 4.5 $0.00007 $0.00224

Measured 2d ago against content hash 60d9a7c5c043, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

coding-guidance-cpp 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.

.agents/skills/coding-guidance-cpp/SKILL.md · 216 lines

How it starts

The opening of the file, as written. The whole thing — 216 lines — stays where its author put it; the contents beside it link to each section on GitHub.

C++ Coding Guidance

This skill adds portable C++ implementation, refactoring, and review guidance.

Adjacent Skills

This skill provides portable C++ engineering principles. Compose with:

  • Workflow: thinking (ambiguous decision framing), recursive-thinking (stress-testing), security (threat modeling)
  • Domain overlays: backend-guidance (server-side code), backend-systems-guidance (stronger backend architecture, reliability, and trust-boundary work), ui-guidance (graphical UI/web frontend), project-core-dev (repo-specific completion discovery and reporting when needed)
  • Qt specialization: coding-guidance-qt when Qt object lifetime, eventing, widgets, models, thread affinity, or generated build steps dominate

When Not to Lean on This Skill

  • non-C++ work
  • legacy or bare-metal environments where modern C++ guidance must be adapted selectively
  • pure architecture or process work with no C++ design or code judgment needed
  • repo-specific style packs or platform policies that should be enforced by local clang-tidy, compiler, or overlay rules rather than a portable principle skill

Boundary Contract

Keep this skill focused on portable C++ engineering judgment.

  • Put repo-specific exception policy, warning policy, formatter choices, and include-order rules in repo config or repo docs
  • Put style-pack rules from ecosystems such as Google, LLVM, Abseil, or platform/vendor bundles in repo config or overlays, not here
  • Put library- or platform-specific API policy in repo config or a domain overlay
  • When a rule is analyzer-shaped but not portable, keep it in clang-tidy config or the reference note rather than adding it to the main skill

Implementation Workflow

  1. Read the touched code, build shape, existing tests, and any nearby docs or shorthand notes before editing.
  2. If the request is partially specified, infer the intended behavior from the existing code and tests. Ask only when multiple plausible C++ designs would change semantics.
  3. Choose the narrowest change that solves the problem without hiding ownership, lifetime, or error-handling contracts.
  4. Implement with simple, strongly typed interfaces and modern C++ defaults.
  5. Add or update tests close to the changed behavior.
  6. Run the narrowest relevant format, build, test, sanitizer, and analyzer targets the repo supports.

Read the full file on GitHub · 216 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. 2d ago First seen · 216 lines · 72 tokens per session scan A 60d9a7c5c043

Subscribe to this mod's changes

coding-guidance-cpp is a skill published in the GitHub repository n-n-code/n-n-code-skills (4 stars, last pushed 4d ago), licensed MIT. It adds 72 tokens to every session and 2,242 once invoked, about $0.0004 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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