What is Masques CLAUDE.md?

A design for temporary roles that AI agents can put on and remove, like actors wearing masks. Each role combines a way of thinking, relevant situation details, and descriptive information.

Use it to define, apply, and remove temporary agent roles while keeping identity separate from knowledge lookup, credentials, and tool access.

It provides one place to define an agent's temporary identity instead of spreading that setup across prompts, tools, permissions, and background information.

How ChrisDBaldwin/Masques configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to ChrisDBaldwin/Masques. 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/ChrisDBaldwin/Masques/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/ChrisDBaldwin/Masques

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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/chrisdbaldwin/masques/claude-md/github.svg)](https://agentmods.dev/instructions/chrisdbaldwin/masques/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/chrisdbaldwin/masques/claude-md"><img src="https://agentmods.dev/badge/instructions/chrisdbaldwin/masques/claude-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.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/chrisdbaldwin/masques/claude-md"><img src="https://agentmods.dev/badge/instructions/chrisdbaldwin/masques/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 3,605 This file is loaded in full into every session.

When invoked 3,605 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.

Model	Per session	Once invoked
Fable 5.1	$0.03605	$0.03605
Opus 5.5	$0.01442	$0.01442
Sonnet 5.5	$0.00721	$0.00721
Haiku 4.5	$0.00361	$0.00361

Measured 2mo ago against content hash ff61d8384471, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

Masques 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 2mo 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 · 325 lines

How it starts

The opening of the file, as written. The whole thing — 325 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

Project Purpose

Masques applies theater's ancient coordination model to AI agents. Just as actors don costumes, adopt roles, and operate within defined boundaries — then step backstage to become themselves again — agents can temporarily assume identities called masques.

The core problem: today agents get configured through scattered mechanisms (system prompts, MCP servers, credentials, knowledge bases, tool permissions). These are disconnected. A masque unifies cognitive identity into a single "become this" operation — one don, one doff, session over.

Masques is "AssumeRole for Agents." A masque is a temporary cognitive identity bundling lens (how to think), context (situational grounding), and attributes (metadata). It's a representation tool that slaps on top of any agent — don, work, doff.

What Masques Own (and Don't)

Masques own cognitive identity — nothing else. Separation of concerns:

Need	Masques	Who Handles It
Identity & framing	Lens + context	Masque itself
Knowledge lookup	Declares need	MCP servers
Credentials	Declares need	Vault/credential managers
Tool bundles	Declares capability	Claude Code MCP config
Performance tracking	Declares interest	Observability (OTEL)

Masque Schema

Every masque is a YAML file with three required fields and three optional fields. The schema is intentionally minimal.

Required Fields

name: string              # Human-readable identifier (minLength: 1)
version: "x.y.z"          # Semantic version (pinned — upgrading is deliberate, not automatic)
lens: |                    # Cognitive framing — the core of the masque
  How to think, how to work, what to refuse.
  This is intent guidance as prose.

Optional Fields

attributes:               # Flexible key-value metadata (additionalProperties: true)
  domain: string          # Primary domain (e.g., "systems-programming")
  tagline: string         # One-line promise (e.g., "every line should teach")
  style: string           # Working style description
  philosophy: string      # Core philosophy
  # Any additional keys are allowed

context: |                # Situational grounding
  Who you're helping. What they value.
  What's the operational environment.

spinnerVerbs:             # Custom activity indicators
  mode: replace           # replace | append | prepend
  verbs:                  # min 1 item
    - "Masque:Verbing"    # e.g., "Codesmith:Forging"

Read the full file on GitHub · 325 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.

2mo ago First seen · 325 lines · 3,605 tokens per session scan A ff61d8384471

Subscribe to this mod's changes

Masques CLAUDE.md is an instructions file published in the GitHub repository ChrisDBaldwin/Masques (14 stars, last pushed 4mo ago), licensed Apache-2.0. It adds 3,605 tokens to every session, about $0.0144 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 2026-08-30.

agentic-identity agentskills claude-plugin

Masques CLAUDE.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
Masques CLAUDE.mdChrisDBaldwin/Masques	Instructions file	14	4mo ago	Apache-2.0	A	3,605	Claude Code
vscode buildNext.instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	9,719	GitHub Copilot
next.js AGENTS.mdvercel/next.js	Instructions file	143k	today	MIT	A	7,461	Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	5,516	GitHub Copilot
langchain AGENTS.mdlangchain-ai/langchain	Instructions file	149k	today	MIT	A	4,680	Codex, OpenCode
vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	3,093	GitHub Copilot
vscode ai-customization.instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	1,907	GitHub Copilot

Masques: Instructions file for Claude Code