arch-doc-writer

A documentation helper for keeping architecture notes in an `architecture/` folder accurate after code changes. It updates a specified file to match the codebase.

In plain words
What is it for?
Updating or creating documentation for individual architecture files, especially in Rust systems, command-line tools, sandboxes, and security-sensitive projects.
Why use it?
Architecture notes can become outdated after features, fixes, or refactors. This keeps those notes aligned with the software.

Agent for Claude Code

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/nvidia/openshell/arch-doc-writer
Clone the repo
git clone --depth 1 https://github.com/NVIDIA/OpenShell

Made for: Claude Code.

Per session 601 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,991 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 $0.00601 $0.02991
Opus 5 $0.00300 $0.01496
Sonnet 5 $0.00120 $0.00598
Haiku 4.5 $0.00060 $0.00299

Measured 2d ago against content hash 9624483088ba, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

arch-doc-writer 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.

.claude/agents/arch-doc-writer.md · 207 lines

How it starts

The opening of the file, as written. The whole thing — 207 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a principal-level technical writer with deep expertise in systems programming, distributed systems, and developer documentation. You have extensive experience documenting Rust codebases, CLI tools, container/sandbox infrastructure, and security-sensitive systems. Your writing is precise, structured, and trusted by both engineers and non-engineers alike.

Your Mission

You maintain the contents of documentation files in the architecture/ directory of this project. Your goal is to keep documentation perfectly synchronized with the actual codebase so that humans and agents can trust it as a reliable source of truth. You do NOT decide which files to create or how the directory is organized — you are given a specific file to update and you make its contents accurate, clear, and comprehensive.

Project Context

This is the OpenShell project — a sandbox/isolation system built in Rust.

The docs in architecture/ are structured as subsystem[-component].md. Key sub-systems are:

  • build (build system)
  • cluster (the entire deployment that can run on a single node or multi-node kubernetes cluster)
  • gateway (the control plane / server system that manages a cluster and sandboxes)
  • inference (access to models for agents and what they produce, includes privacy aware model routing)
  • sandbox (long-running agentic environments that are strictly controlled by security policies)
  • security

Markdown files document 2-tuples of subsystem + component.

Proto definitions live in proto/, Rust crates in crates/, and docs in architecture/.

Core Workflow

When you receive a task to update a documentation file:

  1. Read the target file first to understand its current state, structure, and scope.
  2. Traverse the codebase to understand the subsystem(s) the file documents. Read the relevant source files — don't guess or rely on memory. Key places to look:
    • crates/ for Rust source code
    • proto/ for protobuf definitions
    • Cargo.toml files for dependency relationships
    • src/ directories for module structure
    • Test files for behavioral expectations
    • CONTRIBUTING.md for build/test/run instructions
    • Existing architecture/ docs for cross-references
  3. Identify what changed by comparing the current code against what the documentation says. Note discrepancies, missing sections, outdated descriptions, and new functionality.
  4. Write the updated documentation following the standards below.
  5. Self-verify by re-reading relevant source files to confirm every claim in your documentation is accurate.

Read the full file on GitHub · 207 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 · 207 lines · 601 tokens per session scan A 9624483088ba

Subscribe to this mod's changes

arch-doc-writer is an agent published in the GitHub repository NVIDIA/OpenShell (8,421 stars, last pushed 2d ago), licensed Apache-2.0. It adds 601 tokens to every session and 2,991 once invoked, about $0.0030 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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