Borrowing it
Nothing to install: this file belongs to jimmystridh/willys-mcp. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/jimmystridh/willys-mcp/main/CLAUDE.mdgit clone --depth 1 https://github.com/jimmystridh/willys-mcpWrote 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.
[](https://agentmods.dev/instructions/jimmystridh/willys-mcp/claude-md)<a href="https://agentmods.dev/instructions/jimmystridh/willys-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/jimmystridh/willys-mcp/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.
<a href="https://agentmods.dev/instructions/jimmystridh/willys-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/jimmystridh/willys-mcp/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.01649 | $0.01649 |
| Opus 5 | $0.00825 | $0.00825 |
| Sonnet 5 | $0.00330 | $0.00330 |
| Haiku 4.5 | $0.00165 | $0.00165 |
Grade A, and why
willys-mcp 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 9d 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.
How it starts
The opening of the file, as written. The whole thing — 193 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.
Development Commands
If you need to use the server, you run it yourself on port 3009. Be sure to inspect the output to see if everything works.
Development Server:
PORT=3009 npm run dev # Start development server with Turbopack
Code Quality:
npm run lint # Check code with Biome
npm run format # Format code with Biome
Testing:
# Run comprehensive test suite
node test-search-with-auth.js
# Test individual components
node test-offers.js
node test-search-direct.js
node test-common-products.js
E2E Testing
Always use the end-to-end testing file to test the server. It will test the server and the web UI.
Integration Testing
Also write e2e tests for code paths, these tests should be isolated and not rely on the web UI.
High-Level Architecture
This is a Willys MCP (Model Context Protocol) Server that provides programmatic access to Willys grocery operations through both an MCP server interface and a Next.js web application.
Core Components
-
MCP Server (
app/api/mcp/[transport]/route.ts)- Main entry point with 17 registered tools
- Session-based authentication using SQLite-backed mcpSessionStore
- All tools require sessionId parameter for authentication
- Implements comprehensive Willys API operations
-
Session Management (
lib/mcp-session-store.ts)- SQLite-based session store with 24-hour expiration
- Persistent storage with automatic cleanup
- Maps sessionId to authentication cookies
- Integrates with order cache for efficient cleanup
-
Authentication Layer (
lib/mcp-auth.ts)- Puppeteer-based login automation
- Cookie extraction and session management
- Session validation and cleanup
-
Database Layer (
lib/database.ts)- SQLite database with WAL mode for better performance
- Persistent storage for sessions and order cache
- Automatic schema initialization and cleanup
- Foreign key constraints for data integrity
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.
- 9d ago First seen · 193 lines · 1,649 tokens per session scan A 5b9c31959ef9
willys-mcp CLAUDE.md is an instructions file published in the GitHub repository jimmystridh/willys-mcp (4 stars, last pushed 7mo ago), licensed MIT. It adds 1,649 tokens to every session, about $0.0082 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 2026-08-31.
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