matryca-plumber: Instructions file for Claude Code

CLAUDE.md

matryca-plumber CLAUDE.md is an instructions file for Claude Code from MarcoPorcellato/matryca-plumber. It costs 861 tokens per session, scanned A, original, Apache-2.0.

A project instruction file for auditing and navigating the Matryca Plumber codebase, using an index that maps symbols and their execution flows.

In plain words
What is it for?
It requires impact analysis before changing functions or classes, indexed searches when exploring unfamiliar code, and change detection before commits or regression reviews.
Why use it?
It helps an agent understand the impact of a code change before editing and check afterward that only expected behavior was affected.

Instructions file for Claude Code

Written for Claude Code: the file is CLAUDE.md. Also seen: reads .claude/ paths; mentions AGENTS.md.

This is MarcoPorcellato/matryca-plumber's own configuration. It tells Claude Code how to work on matryca-plumber itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything matryca-plumber configures →

Reuse

Borrowing it

Nothing to install: this file belongs to MarcoPorcellato/matryca-plumber. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/MarcoPorcellato/matryca-plumber/main/CLAUDE.md
Clone the repo
git clone --depth 1 https://github.com/MarcoPorcellato/matryca-plumber

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

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README.md
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<a href="https://agentmods.dev/instructions/marcoporcellato/matryca-plumber/claude-md"><img src="https://agentmods.dev/badge/instructions/marcoporcellato/matryca-plumber/claude-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 861 This file is loaded in full into every session.
When invoked 861 The same file — it is already loaded in full.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00861 $0.00861
Opus 5 $0.00430 $0.00430
Sonnet 5 $0.00172 $0.00172
Haiku 4.5 $0.00086 $0.00086

Measured 7d ago against content hash 33df894cdafa, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

matryca-plumber CLAUDE.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 7d 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.md · 56 lines

How it starts

The opening of the file, as written. The whole thing — 56 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Code Audit — Code Intelligence

This project is indexed for local code audit as matryca-plumber. Use the configured code-audit tools to understand code, assess impact, and navigate safely.

Index stale? Run node .gitnexus/run.cjs analyze from the project root — it auto-selects an available runner. No .gitnexus/run.cjs yet? npx gitnexus analyze (npm 11 crash → npm i -g gitnexus; #1939).

Always Do

  • MUST run impact analysis before editing any symbol. Before modifying a function, class, or method, run impact({target: "symbolName", direction: "upstream"}) and report the blast radius (direct callers, affected processes, risk level) to the user.
  • MUST run detect_changes() before committing to verify your changes only affect expected symbols and execution flows. For regression review, compare against the default branch: detect_changes({scope: "compare", base_ref: "main"}).
  • MUST warn the user if impact analysis returns HIGH or CRITICAL risk before proceeding with edits.
  • When exploring unfamiliar code, use query({search_query: "concept"}) to find execution flows instead of grepping. It returns process-grouped results ranked by relevance.
  • When you need full context on a specific symbol — callers, callees, which execution flows it participates in — use context({name: "symbolName"}).
  • For security review, explain({target: "fileOrSymbol"}) lists taint findings (source→sink flows; needs analyze --pdg).

Never Do

  • NEVER edit a function, class, or method without first running impact on it.
  • NEVER ignore HIGH or CRITICAL risk warnings from impact analysis.
  • NEVER rename symbols with find-and-replace — use rename which understands the call graph.
  • NEVER commit changes without running detect_changes() to check affected scope.

Resources

Resource Use for
gitnexus://repo/matryca-plumber/context Codebase overview, check index freshness
gitnexus://repo/matryca-plumber/clusters All functional areas
gitnexus://repo/matryca-plumber/processes All execution flows
gitnexus://repo/matryca-plumber/process/{name} Step-by-step execution trace

Read the full file on GitHub · 56 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. 7d ago First seen · 56 lines · 861 tokens per session scan A 33df894cdafa

Subscribe to this mod's changes

matryca-plumber CLAUDE.md is an instructions file published in the GitHub repository MarcoPorcellato/matryca-plumber (96 stars, last pushed today), licensed Apache-2.0. It adds 861 tokens to every session, about $0.0043 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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