schemas

schemas is a skill for Claude Code, Codex from MadAppGang/claude-code. It costs 24 tokens per session (1,129 once invoked), scanned A, original, MIT.

Schemas that describe the required YAML header fields for Claude Code agents and commands. YAML frontmatter is the metadata block at the top of a file, such as its name, description, model, and tools.

In plain words
What is it for?
Use it to create or check agent and command frontmatter, including names, descriptions, models, tools, colors, and referenced skills.
Why use it?
It removes uncertainty when creating or validating these files and helps catch invalid field names or values.

Skill for Claude CodeCodex

Part of the agentdev plugin — 5 skills, 5 commands, 3 agents shipped together

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 skills/madappgang/claude-code/schemas
Any agent
npx skills add MadAppGang/claude-code --skill schemas
Clone the repo
git clone --depth 1 https://github.com/MadAppGang/claude-code

Made for: Claude Code, Codex.

Or install agentdev, the plugin that ships this one along with the rest of its 5 skills, 5 commands, 3 agents.

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 schemas

README.md
[![agentmods](https://agentmods.dev/badge/skills/madappgang/claude-code/schemas.svg)](https://agentmods.dev/skills/madappgang/claude-code/schemas)
Your own site
<a href="https://agentmods.dev/skills/madappgang/claude-code/schemas"><img src="https://agentmods.dev/badge/skills/madappgang/claude-code/schemas.svg" alt="Measured on agentmods" height="20"></a>
Per session 24 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,129 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 5.1 $0.00024 $0.01129
Opus 5 $0.00012 $0.00564
Sonnet 5 $0.00005 $0.00226
Haiku 4.5 $0.00002 $0.00113

Measured 5d ago against content hash 80de37f43455, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

schemas 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 5d 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/agentdev/skills/schemas/SKILL.md · 145 lines

How it starts

The opening of the file, as written. The whole thing — 145 lines — stays where its author put it; the contents beside it link to each section on GitHub.

plugin: agentdev updated: 2026-01-20

Frontmatter Schemas

Agent Frontmatter

---
name: agent-name               # Required: lowercase-with-hyphens
description: |                 # Required: detailed with examples
  Use this agent when [scenario]. Examples:
  (1) "Task description" - launches agent for X
  (2) "Task description" - launches agent for Y
  (3) "Task description" - launches agent for Z
model: sonnet                  # Required: sonnet | opus | haiku
color: purple                  # Optional: purple | cyan | green | orange | blue | red
tools: TaskCreate, TaskUpdate, TaskList, TaskGet, Read, Write  # Required: comma-separated, space after comma
skills: skill1, skill2         # Optional: referenced skills
---

Field Reference

Field Required Values Description
name Yes lowercase-with-hyphens Agent identifier
description Yes Multi-line string 3-5 usage examples
model Yes sonnet, opus, haiku AI model to use
color No See colors below Terminal color
tools Yes Tool list Available tools
skills No Skill list Referenced skills

Color Guidelines

Color Agent Type Examples
purple Planning architect, api-architect
green Implementation developer, ui-developer
cyan Review reviewer, designer
orange Testing test-architect, tester
blue Utility cleaner, api-analyst
red Critical/Security (rarely used)

Tool Patterns by Agent Type

Orchestrators (Commands):

  • Must have: Task, TaskCreate, TaskUpdate, TaskList, TaskGet, Read, Bash
  • Often: AskUserQuestion, Glob, Grep
  • Never: Write, Edit

Planners:

  • Must have: TaskCreate, TaskUpdate, TaskList, TaskGet, Read, Write (for docs)
  • Often: Glob, Grep, Bash

Implementers:

  • Must have: TaskCreate, TaskUpdate, TaskList, TaskGet, Read, Write, Edit
  • Often: Bash, Glob, Grep

Read the full file on GitHub · 145 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. 5d ago First seen · 145 lines · 24 tokens per session scan A 80de37f43455

Subscribe to this mod's changes

schemas is a skill published in the GitHub repository MadAppGang/claude-code (279 stars, last pushed 5mo ago), licensed MIT. It adds 24 tokens to every session and 1,129 once invoked, about $0.0001 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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