# Simple Product Requirements Document: MCP STDIO to HTTP Utility

## Problem Statement

### Problem Definition
Developers need a sharable utility to convert MCP (Model Context Protocol) tools that use STDIO transport into HTTP streamable endpoints. Currently, MCP tools are limited to STDIO communication, which restricts their accessibility and integration capabilities in web-based applications and distributed systems.

### Target Users
- Full-stack developers building AI-powered applications
- DevOps engineers integrating MCP tools into CI/CD pipelines
- Frontend developers needing browser-based MCP tool access
- Teams wanting to expose MCP functionality via REST APIs

### Business Value
This utility enables broader adoption of MCP tools by providing HTTP transport layer, allowing seamless integration into web applications, microservices architectures, and cloud-native deployments. It reduces development friction and expands the ecosystem of available AI tools accessible via standard HTTP protocols.

## Solution Overview

### Solution Summary
Create a sharable utility that bridges MCP STDIO tools to HTTP streaming endpoints using FastHonoMcp as the HTTP server framework and ModalityClient for STDIO MCP connections. The utility will dynamically load tools from specified MCP packages and expose them as HTTP endpoints.

### Key Features
1. **Dynamic Tool Loading**: Automatically discover and load tools from STDIO MCP packages
2. **HTTP Streaming**: Convert STDIO communication to HTTP streamable responses
3. **Package Flexibility**: Support any npm-published MCP package (demonstrated with chrome-devtools-mcp)
4. **Environment Configuration**: Handle Chrome/browser executable paths for tool compatibility
5. **Timeout Management**: Configurable timeouts for long-running operations

### User Flow
1. Developer specifies MCP package name (e.g., "chrome-devtools-mcp@latest")
2. Utility spawns STDIO process using ModalityClient
3. Tools are dynamically discovered via listTool method
4. HTTP server exposes discovered tools as endpoints
5. Clients make HTTP requests to execute MCP tools
6. Responses are streamed back via HTTP

## Core Requirements

### Must-Have Features
- Support for chrome-devtools-mcp@latest as initial demo implementation
- Dynamic tool loading using ModalityClient.listTool()
- HTTP server implementation using FastHonoMcp
- Environment variable handling for Chrome executable paths
- Bunx/npx fallback for package execution
- 2-minute timeout configuration for browser operations
- Integration with existing src/mcp-tools.ts structure

### Technical Constraints
- Must use FastHonoMcp from "modality-mcp-kit" package
- Must use ModalityClient from "modality-ai" package
- Implementation must modify src/mcp-tools.ts
- Support headless Chrome configuration
- Maintain compatibility with existing MCP SDK transport mechanisms

### Performance Goals
- Tool discovery and loading within 30 seconds
- HTTP response streaming for large tool outputs
- Support for concurrent tool executions
- Memory efficient subprocess management
- Graceful error handling and cleanup

## Timeline & Success Metrics

### Major Milestones
1. **Phase 1 (Week 1)**: Core utility architecture and ModalityClient integration
2. **Phase 2 (Week 2)**: FastHonoMcp HTTP server implementation
3. **Phase 3 (Week 2)**: Dynamic tool loading and chrome-devtools-mcp integration
4. **Phase 4 (Week 3)**: Testing, documentation, and package publishing

### Success Metrics
- Successful loading of all chrome-devtools-mcp tools via HTTP endpoints
- Response time < 5 seconds for tool discovery
- 100% compatibility with existing MCP STDIO transport
- Zero memory leaks in subprocess management
- Positive developer feedback on ease of integration

### Launch Criteria
- All chrome-devtools-mcp tools accessible via HTTP
- Comprehensive error handling for edge cases
- Documentation with usage examples
- Unit tests covering core functionality
- Successful demo with real browser automation tasks