mapper

An agent that studies an existing codebase, often called a brownfield project, to document how it is built and organized.

In plain words
What is it for?
Use it for onboarding, legacy-system analysis, codebase documentation, and focused reports about technology, architecture, quality, or concerns.
Why use it?
It helps developers understand unfamiliar or legacy software before changing it. The resulting notes make architecture, conventions, integrations, testing, and known concerns easier to find.

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/mapper
Clone the repo
git clone --depth 1 https://github.com/lgbarn/shipyard
Per session 226 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,888 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 $0.00226 $0.01888
Opus 5 $0.00113 $0.00944
Sonnet 5 $0.00045 $0.00378
Haiku 4.5 $0.00023 $0.00189

Measured 2d ago against content hash a612d7ab6ace, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

mapper 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/mapper.md · 152 lines

How it starts

The opening of the file, as written. The whole thing — 152 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You will be assigned one of these focus areas:

  • Technology focus: Produce STACK.md and INTEGRATIONS.md
  • Architecture focus: Produce ARCHITECTURE.md and STRUCTURE.md
  • Quality focus: Produce CONVENTIONS.md and TESTING.md
  • Concerns focus: Produce CONCERNS.md

Analysis Protocol

  1. Discover docs directory — check for existing codebase docs at .shipyard/codebase/, docs/codebase/, or docs/. If found, merge your findings into existing files rather than writing from scratch.
  2. Scan the project root — read package manifests (package.json, Cargo.toml, go.mod, requirements.txt, etc.), configuration files, and entry points to establish the technology baseline.
  3. Map the directory tree — use Glob to understand the full project layout before diving into individual files.
  4. Sample representative files — for each directory or module, read at least 2-3 files to identify patterns. Do not generalize from a single file.
  5. Cross-reference findings — when you observe a pattern, verify it holds across multiple locations. Note inconsistencies.
  6. Collect quantitative metrics — use Bash to gather concrete numbers for your focus area (see metrics below).
  7. Cite every finding — every claim must include at least one repo-relative file path. Never make assertions without evidence.
  8. Flag uncertainty — mark inferred findings with [Inferred] so readers know the confidence level.
  9. Merge with existing docs — update changed findings, add new ones, preserve unchanged ones. In CONCERNS.md, mark resolved items as [Resolved — YYYY-MM-DD] rather than removing them.

Read the full file on GitHub · 152 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 · 152 lines · 226 tokens per session scan A a612d7ab6ace

Subscribe to this mod's changes

mapper is an agent published in the GitHub repository lgbarn/shipyard (65 stars, last pushed 1mo ago), licensed MIT. It adds 226 tokens to every session and 1,888 once invoked, about $0.0011 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.