mullion-ts: Instructions file for Claude Code

CLAUDE.md

mullion-ts CLAUDE.md is an instructions file for Claude Code from mullionlabs/mullion-ts. It costs 3,329 tokens per session, scanned A, original, MIT.

A project instruction guide for Mullion, a TypeScript library that checks how information is managed in workflows involving large language models.

In plain words
What is it for?
Use it when developing, testing, building, or organising Mullion's TypeScript packages and shared AI-context utilities.
Why use it?
It documents the library's design, tools, package layout, and development commands so changes follow the project's compile-time safety approach. A monorepo is one repository containing several related packages.

Instructions file for Claude Code

Written for Claude Code: the file is CLAUDE.md. Also seen: mentions CLAUDE.md; mentions Claude Code.

This is mullionlabs/mullion-ts's own configuration. It tells Claude Code how to work on mullion-ts 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 mullion-ts configures →

Reuse

Borrowing it

Nothing to install: this file belongs to mullionlabs/mullion-ts. 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/mullionlabs/mullion-ts/main/CLAUDE.md
Clone the repo
git clone --depth 1 https://github.com/mullionlabs/mullion-ts

Made for: Claude Code.

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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 $0.03329 $0.03329
Opus 5 $0.01665 $0.01665
Sonnet 5 $0.00666 $0.00666
Haiku 4.5 $0.00333 $0.00333

Measured 8d ago against content hash 37256eb01cd6, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

mullion-ts 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 8d 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 · 424 lines

How it starts

The opening of the file, as written. The whole thing — 424 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Mullion Development Guide

Project Overview

Mullion — TypeScript library for type-safe LLM context management.

Core philosophy: Compile-time safety, not runtime orchestration. We are ESLint + TypeScript for LLM workflows, not a new LangChain.

One-liner: "Catch context leaks and confidence issues before runtime"

Current version: 0.2.0 (all packages) Repository: https://github.com/mullionlabs/mullion-ts

Tech Stack

  • Monorepo: pnpm workspaces + Turborepo
  • Versioning: Changesets (independent releases)
  • Build: tsup
  • Testing: Vitest
  • CI/CD: GitHub Actions
  • Git hooks: Husky + lint-staged
  • Linting: ESLint 9 (flat config) + TypeScript ESLint v8
  • Formatting: Prettier
  • Schemas: Zod v4.1.8+ (for AI SDK 5+ compatibility)

Project Structure

mullion/
├── packages/
│   ├── core/                 # @mullion/core
│   │   ├── src/
│   │   │   ├── owned.ts      # Owned<T, S> type
│   │   │   ├── semantic-value.ts # SemanticValue type
│   │   │   ├── context.ts    # Context implementation
│   │   │   ├── scope.ts      # scope() function
│   │   │   ├── bridge.ts     # bridge utilities
│   │   │   ├── brand.ts      # nominal typing utilities
│   │   │   ├── fork/         # fork/merge implementations
│   │   │   ├── merge/        # merge strategies
│   │   │   ├── trace/        # OpenTelemetry tracing
│   │   │   └── index.ts
│   │   ├── package.json
│   │   ├── tsconfig.json
│   │   └── tsup.config.ts
│   │
│   ├── eslint-plugin/        # @mullion/eslint-plugin
│   │   ├── src/
│   │   │   ├── rules/
│   │   │   │   ├── no-context-leak.ts
│   │   │   │   └── require-confidence-check.ts
│   │   │   └── index.ts
│   │   └── ...
│   │
│   └── ai-sdk/               # @mullion/ai-sdk
│       ├── src/
│       │   ├── client.ts     # Mullion client implementation
│       │   ├── cache/        # provider-aware caching
│       │   ├── cost/         # cost estimation & tracking
│       │   └── index.ts
│       └── ...
│
├── examples/
│   └── basic/                # Working examples
│
├── docs/
│   ├── adr/                  # Architecture Decision Records
│   ├── contributing/         # Contribution guides
│   ├── design/               # Design documents
│   ├── guides/               # User guides
│   ├── reference/            # API reference
│   └── README.md             # Documentation index
│
├── .changeset/               # Changesets config
├── .github/workflows/        # CI/CD
├── turbo.json               # Turborepo config
├── pnpm-workspace.yaml
├── tsconfig.base.json
└── package.json

Read the full file on GitHub · 424 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. 8d ago First seen · 424 lines · 3,329 tokens per session scan A 37256eb01cd6

Subscribe to this mod's changes

mullion-ts CLAUDE.md is an instructions file published in the GitHub repository mullionlabs/mullion-ts (20 stars, last pushed 1mo ago), licensed MIT. It adds 3,329 tokens to every session, about $0.0166 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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