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.
npx agentmods add rules/cafreeman/foundry-mcp/foundrygit clone --depth 1 https://github.com/cafreeman/foundry-mcpWhat 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 | $0.05368 | $0.05368 |
| Opus 5 | $0.02684 | $0.02684 |
| Sonnet 5 | $0.01074 | $0.01074 |
| Haiku 4.5 | $0.00537 | $0.00537 |
Grade A, and why
Foundry MCP Usage Guide 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 2d 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 — 530 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Foundry MCP Usage Guide for AI Assistants
Overview
Foundry MCP is a project management tool designed specifically for AI coding assistants. It provides structured project context, specification management, and workflow guidance through a standardized directory structure in ~/.foundry/.
Key Principles:
- Content Agnostic: Foundry manages structure, not content opinions
- LLM-Driven: You provide complete content as arguments
- User-Controlled: Users control content, CLI manages structure
- Workflow-Aware: Tools provide next-steps guidance for efficient development
CRITICAL: Understanding Document Purpose
These documents serve as COMPLETE CONTEXT for future LLMs and developers:
- Each document must contain ALL information needed for someone with no prior project knowledge
- Future LLMs will load these as PRIMARY reference for implementation work
- Apply "Cold Start Test": Could a skilled developer implement using only this document?
- Documents must be self-contained with comprehensive architectural and business context
- Include implementation prerequisites, dependencies, decision rationale, and edge cases
Document Creation Mindset:
- Write for someone who has never seen this project before
- Include WHY decisions were made, not just WHAT was decided
- Provide complete technical and business context for implementation
- Assume the reader needs to understand the full system to implement successfully
Core Concepts
Project Structure
Each Foundry project contains:
vision.md: High-level product vision and goals (200+ characters, you provide)tech-stack.md: Technology decisions and architecture (150+ characters, you provide)summary.md: Concise context for quick LLM consumption (100+ characters, you provide)specs/: Directory containing timestamped feature specifications
Specification Structure
Each spec contains:
spec.md: Detailed feature requirements, acceptance criteria, implementation approachtask-list.md: Implementation checklist with checkboxes (- [ ] task, - [x] completed)notes.md: Additional context, design decisions, and implementation notes
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.
- 2d ago First seen · 530 lines · 5,368 tokens per session scan A 52749713a47d
Foundry MCP Usage Guide is a cursor rule published in the GitHub repository cafreeman/foundry-mcp (4 stars, last pushed 5mo ago), licensed MIT. It adds 5,368 tokens to every session, about $0.0268 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.
Other cursor rules, from other repositories
angular-20
This rule provides comprehensive best practices and coding standards for Angular development, focusing on modern TypeScript, standalone components, signals, and performance optimizations.
dev-standard
Apache Superset development standards and guidelines for Cursor IDE.
typescript
Changes to these high-fan-out internals can affect every message, delta, element, or rerun. Keep work in them minimal, and benchmark changes with representative stress-test apps.
coolify-ai-docs
Master reference to all Coolify AI documentation in .ai/ directory.
python_lib
Tips and guidelines specific to the development of the Streamlit Python library, not applicable to scripts and e2e tests.
specs
This directory contains product and tech specs for Streamlit features.