subsystem-md

subsystem-md is a skill for Claude Code, Codex from leefowlercu/agent-kit. It costs 10 tokens per session (2,166 once invoked), scanned A, original, MIT.

A skill for creating or updating documentation about one subsystem, meaning one distinct part of a larger software project. The document is stored as a README file under `docs/subsystems`.

In plain words
What is it for?
It helps create missing subsystem documentation or reconcile an existing document with the current codebase.
Why use it?
It gives developers a consistent place to explain what a subsystem does, how it is designed, and how it connects to other parts of the project. It keeps the explanation high-level rather than tied to changing implementation details.

Skill for Claude CodeCodex

Written for Claude Code and Codex: disable-model-invocation in frontmatter, but also agents/openai.yaml present. Also seen: mentions subagents.

Part of the project-docs-reconciler plugin — 3 skills shipped together

Good fit It helps create missing subsystem documentation or reconcile an existing document with the current codebase.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/leefowlercu/agent-kit/subsystem-md
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.

Any agent
npx skills add leefowlercu/agent-kit --skill subsystem-md
Clone the repo
git clone --depth 1 https://github.com/leefowlercu/agent-kit

Made for: Claude Code, Codex.

Or install project-docs-reconciler, the plugin that ships this one along with the rest of its 3 skills.

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.

agentmods badge for subsystem-md

README.md
[![agentmods](https://agentmods.dev/badge/skills/leefowlercu/agent-kit/subsystem-md/github.svg)](https://agentmods.dev/skills/leefowlercu/agent-kit/subsystem-md)
Your own site
<a href="https://agentmods.dev/skills/leefowlercu/agent-kit/subsystem-md"><img src="https://agentmods.dev/badge/skills/leefowlercu/agent-kit/subsystem-md/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for subsystem-md

Your own site · 80×15
<a href="https://agentmods.dev/skills/leefowlercu/agent-kit/subsystem-md"><img src="https://agentmods.dev/badge/skills/leefowlercu/agent-kit/subsystem-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 10 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,166 The whole file, excluding the scripts and references it only reads on demand.
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 $0.00010 $0.02166
Opus 5.5 $0.00004 $0.00866
Sonnet 5.5 $0.00002 $0.00433
Haiku 4.5 $0.00001 $0.00217

Measured 1mo ago against content hash be531d58cf5b, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

subsystem-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 1mo 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.

plugins/project-docs-reconciler/skills/subsystem-md/SKILL.md · 165 lines

How it starts

The opening of the file, as written. The whole thing — 165 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Expected Input

Use the subsystem name supplied by the user as <subsystem-name>.

The subsystem documentation file is located at docs/subsystems/<subsystem-name>/README.md.

Check if this file exists:

  • If it does not exist: Proceed to Initialization Mode
  • If it exists: Proceed to Reconciliation Mode

Shared Guidelines

When drafting or updating this documentation, you

  • MUST focus on the high-level aspects of the requested subsystem, ensuring that it provides clear insights into its functionality, design principles, and interactions with other parts of the system.
  • MUST NOT include low-level implementation details, code snippets, or exhaustive technical specifications, as those may change frequently during development.
  • MUST ensure that the documentation is accurate and reflects the current state of the requested subsystem as understood from your analysis of the codebase.
  • MUST strike a balance between being comprehensive and concise, providing enough information to be useful without overwhelming the reader with unnecessary details.

Section Description Syntax: **<section-identifier>: <section-level>** { - section-title} - <section-description> { - section-example} {, section-example}...

Section Description Examples:

  • **Subsystem Title: H1** - The name of the subsystem in Title Case.
  • **Subsystem Tagline: N/A** - A brief, catchy tagline that summarizes the subsystem's purpose or mission.
  • **Documented Version: N/A** - The current documented version of the subsystem. - **Documented Version**: v0.1.0, **Documented Version**: N/A
  • **Design Principles: H2** - Design Principles - An explanation of the core design principles and architectural patterns.

The structure of the subsystem README.md file MUST include ONLY the following sections, in order:

  1. Subsystem Title: H1 - The name of the subsystem in Title Case. Derive a suitable title based on the subsystem's purpose and functionality.
  2. Subsystem Tagline: N/A - A brief, catchy tagline that summarizes the subsystem's purpose or mission.
  3. Documented Version: N/A - The version of the requested subsystem being documented, derived from git tags or version files. If no versioning is found use "N/A". - **Documented Version**: v0.13.0, **Documented Version**: N/A
  4. Last Updated: N/A - The date when the documentation was last updated. Use the format YYYY-MM-DD. - **Last Updated**: 2024-06-15
  5. ToC: H2 - Table of Contents - A markdown table of contents that links to the subsequent header sections in the README.md.
  6. Overview: H2 - Overview - A brief, high-level description of the requested subsystem, its purpose, goals, and key features.
  7. Design Principles: H2 - Design Principles - An explanation of the core design principles and architectural patterns that guide the development of the requested subsystem.
  8. Key Components: H2 - Key Components - A high-level description of the main components or modules that make up the requested subsystem.
  9. Integration Points: H2 - Integration Points - An outline of how the requested subsystem integrates with other subsystems or components within the codebase.
  10. Glossary: H2 - Glossary - Definitions of any specialized terms or concepts relevant to the requested subsystem.

Read the full file on GitHub · 165 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 1mo ago Changed · +1 lines be531d58cf5b
  2. 1mo ago First seen · 164 lines · 10 tokens per session scan A 6bc403d0c13e

Subscribe to this mod's changes

subsystem-md is a skill published in the GitHub repository leefowlercu/agent-kit (7 stars, last pushed 1mo ago), licensed MIT. It adds 10 tokens to every session and 2,166 once invoked, about $0.0000 per session on Opus 5.5. 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.

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