plumb AGENTS.md

Repository instructions for plumb, a Rust design-system linter that checks rendered websites for consistent visual rules. It provides both a command-line program and an MCP server for AI coding agents.

In plain words
What is it for?
Use it when modifying plumb's rule engine, command-line interface, MCP server, browser integration, configuration, or documentation.
Why use it?
It explains the project's architecture, source-of-truth specification, and boundaries between components, helping changes remain deterministic and correctly placed.

Instructions file for CodexOpenCode

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 instructions/aram-devdocs/plumb/agents-md
Clone the repo
git clone --depth 1 https://github.com/aram-devdocs/plumb

Made for: Codex, OpenCode.

Per session 1,100 This file is loaded in full into every session.
When invoked 1,100 The same file — it is already loaded in full.
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 $0.01100 $0.01100
Opus 5 $0.00550 $0.00550
Sonnet 5 $0.00220 $0.00220
Haiku 4.5 $0.00110 $0.00110

Measured yesterday against content hash 0b91b94cabbc, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

plumb AGENTS.md 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.md · 65 lines

How it starts

The opening of the file, as written. The whole thing — 65 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md

This file is the tool-agnostic entry point for every AI coding agent working in this repository — Claude Code, Codex, Cursor, Windsurf, and any future assistant that honors the AGENTS.md convention.

The same content is surfaced to Claude Code via the CLAUDE.md symlink at the repo root.

What Plumb is

Plumb is a deterministic design-system linter for rendered websites. It ships as a single Rust binary with two entry points:

  • plumb lint <url> — CLI for developers and CI.
  • plumb mcp — Model Context Protocol server for AI coding agents.

The complete product specification lives at docs/local/prd.md. Read the PRD before making non-trivial changes. It is the single source of truth for scope, architecture, determinism invariants, output formats, and release targets.

Repository layout

  • crates/plumb-core/ — rule engine, types, determinism guarantees. No I/O, no async, no wall-clock.
  • crates/plumb-cli/ — clap-based binary. Only crate allowed to print to stdout/stderr.
  • crates/plumb-mcp/ — rmcp stdio server.
  • crates/plumb-cdp/ — Chromium DevTools Protocol driver. Only crate permitted to use unsafe.
  • crates/plumb-config/ — config file loading + JSON Schema emission.
  • crates/plumb-format/ — output formatters (pretty, JSON, SARIF, MCP-compact).
  • docs/src/ — mdBook source for https://plumb.aramhammoudeh.com.
  • docs/adr/ — architecture decision records.
  • docs/local/ — gitignored scratch space for local-only docs (PRD lives here until extracted).
  • .agents/ — tool-agnostic AI library (rules, skills, role specs).
  • .claude/ — Claude Code runtime (settings, hooks, agents). .claude/rules and .claude/skills symlink into .agents/.

Read order

  1. This file.
  2. docs/local/prd.md — product requirements document.
  3. .agents/rules/ — project-specific rules (determinism, dependency hierarchy, rule engine patterns, MCP tool patterns, testing, documentation).
  4. .agents/skills/ — reusable skills (humanizer, code review, etc.).
  5. CONTRIBUTING.md — human contributor guide; covers commit conventions and the dev loop.

Read the full file on GitHub · 65 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 · 65 lines · 1,100 tokens per session scan A 0b91b94cabbc

Subscribe to this mod's changes

plumb AGENTS.md is an instructions file published in the GitHub repository aram-devdocs/plumb (2 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 1,100 tokens to every session, about $0.0055 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.