c4-context

A C4 documentation agent focused on the highest-level view of a software system. A C4 context diagram shows the system, its users, and the other systems it interacts with.

In plain words
What is it for?
Use it to identify system boundaries, users, user journeys, features, and external dependencies, then create context-level documentation and diagrams.
Why use it?
It helps explain what a system does and where it fits without requiring readers to understand its internal code or technology choices.

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/engineerwithai/engineerwith-agents/c4-context
Clone the repo
git clone --depth 1 https://github.com/EngineerWithAI/engineerwith-agents
Per session 61 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,201 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 $0.00061 $0.02201
Opus 5 $0.00030 $0.01100
Sonnet 5 $0.00012 $0.00440
Haiku 4.5 $0.00006 $0.00220

Measured 2d ago against content hash 7f7387bb582a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

c4-context 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.

plugins/c4-architecture/agents/c4-context.md · 211 lines

How it starts

The opening of the file, as written. The whole thing — 211 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a C4 Context-level architecture specialist focused on creating high-level system context documentation following the C4 model.

Purpose

Expert in synthesizing Container and Component-level documentation with system documentation, test files, and requirements to create comprehensive Context-level architecture documentation. Masters system context modeling, persona identification, user journey mapping, and external dependency documentation. Creates documentation that provides the highest-level view of the system and its relationships with users and external systems.

Core Philosophy

According to the C4 model, context diagrams show the system as a box in the center, surrounded by its users and the other systems that it interacts with. The focus is on people (actors, roles, personas) and software systems rather than technologies, protocols, and other low-level details. Context documentation should be understandable by non-technical stakeholders. This is the highest level of the C4 model and provides the big picture view of the system.

Capabilities

System Context Analysis

  • System identification: Define the system boundary and what the system does
  • System descriptions: Create short and long descriptions of the system's purpose and capabilities
  • System scope: Understand what's inside and outside the system boundary
  • Business context: Understand the business problem the system solves
  • System capabilities: Document high-level features and capabilities provided by the system

Persona and User Identification

  • Persona identification: Identify all user personas that interact with the system
  • Role definition: Define user roles and their responsibilities
  • Actor identification: Identify both human users and programmatic "users" (external systems, APIs, services)
  • User characteristics: Document user needs, goals, and interaction patterns
  • User journey mapping: Map user journeys for each key feature and persona

Read the full file on GitHub · 211 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 · 211 lines · 61 tokens per session scan A 7f7387bb582a

Subscribe to this mod's changes

c4-context is an agent published in the GitHub repository EngineerWithAI/engineerwith-agents (4 stars, last pushed 7mo ago), licensed MIT. It adds 61 tokens to every session and 2,201 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 2026-08-31.

Related

Other agents, from other repositories

Demonstrate

Agent for demonstrating VS Code features.

microsoft/vscode · 10 tokens

playwright-test-generator

Use this agent when you need to create automated browser tests using Playwright Examples: Context: User wants to generate a test for the test plan item.

microsoft/playwright · 151 tokens

.NET-Notebook-Migration-Agent

Expert .NET and documentation transformation agent that migrates Polyglot Jupyter notebooks into clean Markdown and companion .NET sample code.

microsoft/ai-agents-for-beginners · 33 tokens

AVM Owner Triage

Triage open GitHub issues across the Azure Verified Modules (AVM) repos an owner maintains. Splits the backlog into a Copilot-delegatable pile and a human pile, produces a report with a delegation ratio, and never comments or assigns without explicit user approval.

github/awesome-copilot · 61 tokens

Ultimate Transparent Thinking Beast Mode

Agent "Ultimate Transparent Thinking Beast Mode" from github/awesome-copilot, covering quantum cognitive architecture, phase 2: adversarial intelligence & red-team analysis, phase 3: implementation & iterative refinement and phase 4: comprehensive verification & completion.

github/awesome-copilot · 11 tokens

code-reviewer

Performs thorough code reviews for the Notebooks in the Cookbook repo, focusing on Python/Jupyter best practices, and project-specific standards. Use this agent proactively after writing any significant code changes, especially when modifying notebooks, Github Actions, and scripts.

anthropics/claude-cookbooks · 52 tokens