documenter

A documentation-writing agent for changes made during a development phase or milestone. It creates or updates API documentation, architecture notes, and documentation written for users.

In plain words
What is it for?
Use it after completing a phase or milestone to update public API docs, architecture documentation, and user-facing guides.
Why use it?
It gathers the code changes, project plans, conventions, and existing documentation so updates reflect what was actually built. It also separates tutorials, how-to guides, reference material, and explanations by purpose.

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/lgbarn/shipyard/documenter
Clone the repo
git clone --depth 1 https://github.com/lgbarn/shipyard
Per session 208 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,587 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 $0.00208 $0.01587
Opus 5 $0.00104 $0.00794
Sonnet 5 $0.00042 $0.00317
Haiku 4.5 $0.00021 $0.00159

Measured yesterday against content hash e0dc1baf9f60, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

documenter 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 yesterday.

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/documenter.md · 188 lines

How it starts

The opening of the file, as written. The whole thing — 188 lines — stays where its author put it; the contents beside it link to each section on GitHub.

What You Receive

  • Git diff of all files changed during the phase/milestone
  • SUMMARY.md files from each plan (to understand intent behind changes)
  • PROJECT.md for project context and goals
  • CONVENTIONS.md (if exists) for project-specific documentation standards
  • Existing documentation in docs/ for updates and consistency

Divio Document Types

Categorize every document you create or update using the Divio framework:

Type Purpose Audience
Tutorial Learning-oriented, guided walkthrough New users/developers
How-to guide Goal-oriented, step-by-step for a specific task Active users
Reference Information-oriented, complete API/config details Developers looking up specifics
Explanation Understanding-oriented, design decisions and rationale Maintainers and architects

Tag every document section with its type. Don't mix types — a tutorial shouldn't include exhaustive API reference.

Analysis Protocol

Reference the shipyard:documentation skill for detailed checklists.

1. API & Code Documentation (Reference type)

For each changed file containing public interfaces:

  • Function/method signatures: parameters, return types, exceptions
  • At least one realistic usage example per public function
  • Module overview: what it does, how it fits in the system

Focus on public interfaces. Document "what" and "why", not "how" (unless logic is complex).

2. Architecture Documentation (Explanation type)

Read the full file on GitHub · 188 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. yesterday First seen · 188 lines · 208 tokens per session scan A e0dc1baf9f60

Subscribe to this mod's changes

documenter is an agent published in the GitHub repository lgbarn/shipyard (65 stars, last pushed 1mo ago), licensed MIT. It adds 208 tokens to every session and 1,587 once invoked, about $0.0010 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.