c4-architecture

c4-architecture is a skill for Claude Code, Codex from coco-research/coco. It costs 40 tokens per session (2,644 once invoked), scanned A, original, no licence file.

A skill for documenting software architecture with C4 model diagrams in Mermaid. The C4 model shows a system at different levels, from its surrounding users and systems down to its internal parts.

In plain words
What is it for?
Use it to create context, container, component, or deployment diagrams for architecture documentation.
Why use it?
It gives teams a consistent way to explain how a software system is structured.

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/coco-research/coco/c4-architecture
Any agent
npx skills add coco-research/coco --skill c4-architecture
Clone the repo
git clone --depth 1 https://github.com/coco-research/coco

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 c4-architecture

README.md
[![agentmods](https://agentmods.dev/badge/skills/coco-research/coco/c4-architecture.svg)](https://agentmods.dev/skills/coco-research/coco/c4-architecture)
Your own site
<a href="https://agentmods.dev/skills/coco-research/coco/c4-architecture"><img src="https://agentmods.dev/badge/skills/coco-research/coco/c4-architecture.svg" alt="Measured on agentmods" height="20"></a>
Per session 40 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,644 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin unknown 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 $0.00040 $0.02644
Opus 5 $0.00020 $0.01322
Sonnet 5 $0.00008 $0.00529
Haiku 4.5 $0.00004 $0.00264

Measured 5d ago against content hash a8a8d19bdc43, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

c4-architecture 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/c4-architecture/SKILL.md · 299 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

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. 5d ago First seen · 299 lines · 40 tokens per session scan A a8a8d19bdc43

Subscribe to this mod's changes

c4-architecture is a skill published in the GitHub repository coco-research/coco (218 stars, last pushed yesterday), with no licence file. It adds 40 tokens to every session and 2,644 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.

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