sleeper-mcp-server: Instructions file for Claude Code

CLAUDE.md

sleeper-mcp-server CLAUDE.md is an instructions file for Claude Code from gmendonc/sleeper-mcp-server. It costs 3,691 tokens per session, scanned A, original, MIT.

A project instruction file for Claude Code that explains how to develop a Sleeper fantasy-football server. Sleeper is a service for managing fantasy-football leagues, and the server connects to its API so an assistant can work with league data.

In plain words
What is it for?
Developing the server, including its API client, data flow, layered structure, and features for managing several fantasy-football leagues.
Why use it?
It gives the coding assistant the project's goals, architecture, and development approach instead of leaving those details unclear.

Instructions file for Claude Code

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

This is gmendonc/sleeper-mcp-server's own configuration. It tells Claude Code how to work on sleeper-mcp-server 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 sleeper-mcp-server configures →

Reuse

Borrowing it

Nothing to install: this file belongs to gmendonc/sleeper-mcp-server. 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/gmendonc/sleeper-mcp-server/main/CLAUDE.md
Clone the repo
git clone --depth 1 https://github.com/gmendonc/sleeper-mcp-server

Made for: Claude Code.

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Per session 3,691 This file is loaded in full into every session.
When invoked 3,691 The same file — it is already loaded in full.
Security scan A 1 finding. 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 $0.03691 $0.03691
Opus 5.5 $0.01476 $0.01476
Sonnet 5.5 $0.00738 $0.00738
Haiku 4.5 $0.00369 $0.00369

Measured 2mo ago against content hash cf313af89f9f, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

sleeper-mcp-server CLAUDE.md scanned grade A with 1 finding 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl "https://api.sleeper.app/v1/user/USERNAME"
CLAUDE.md · 371 lines

How it starts

The opening of the file, as written. The whole thing — 371 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CLAUDE.md - Sleeper MCP Server Development Guide

This guide helps Claude Code understand and develop the Sleeper MCP Server, a TypeScript-based Model Context Protocol server that connects Claude Desktop to the Sleeper fantasy football API for intelligent multi-league management.

Project Philosophy and Goals

The Sleeper MCP Server exists to solve a specific problem: fantasy football players managing multiple leagues (typically 4-8) spend over three hours weekly on repetitive research and roster management. This project reduces that time to under one hour through AI-powered cross-league analysis.

The core philosophy is "Ship fast, iterate faster" - we prioritize working functionality that provides immediate value, then enhance based on actual usage patterns. The project uses AI-assisted development with Claude and GitHub Copilot, but architectural decisions remain human-driven to ensure user-centered design.

Understanding the Architecture

The Three-Layer Design

The project follows a clean three-layer architecture that separates concerns and makes the codebase maintainable:

Layer 1: API Client (sleeper-api.ts) This layer handles all communication with Sleeper's REST API. Think of it as a translator that speaks Sleeper's language. It includes intelligent caching to avoid overwhelming Sleeper's servers with redundant requests, which is crucial when analyzing multiple leagues simultaneously. The caching system stores responses for five minutes by default, dramatically improving performance for multi-league operations.

Layer 2: Business Logic (tools.ts) This is where the magic happens - raw API data gets transformed into meaningful insights. The tools layer takes information from multiple API calls, correlates it, enriches it with context, and formats it for human consumption. For example, when discovering leagues, it doesn't just list them - it calculates win percentages, identifies which leagues need attention, and sorts everything by relevance.

Read the full file on GitHub · 371 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. 2mo ago First seen · 371 lines · 3,691 tokens per session scan A cf313af89f9f

Subscribe to this mod's changes

sleeper-mcp-server CLAUDE.md is an instructions file published in the GitHub repository gmendonc/sleeper-mcp-server (2 stars, last pushed 1y ago), licensed MIT. It adds 3,691 tokens to every session, about $0.0148 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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