MCP Implementation Research

MCP Implementation Research

Quick Start

What are you doing?

• 📝 Reviewing MCP server → references/​implementation-checklist.md
• 🚀 Planning MCP feature → references/​protocol-patterns.md
• 🐛 Protocol issue → references/​common-pitfalls.md
• ✅ Architecture validation → All references + latest spec

Research Workflow

1. Understand implementation - What MCP capabilities? Which transport? What security requirements?
2. Consult references - Load relevant reference files progressively
3. Check latest spec - WebFetch https://modelcontextprotocol.io/​specification/​2025-06-18
4. Search community - WebSearch for "MCP [specific-issue] 2025"
5. Validate compliance - Protocol compliance, security, best practices
6. Report findings - Structured format (see examples/)

Critical MCP Requirements

Protocol Compliance (JSON-RPC 2.0)

• All messages MUST include jsonrpc: "2.0"
• Responses include result OR error, never both
• Initialization: initialize → response → initialized notification
• Use standard error codes (-32xxx)

Security & Consent

• User consent MUST be obtained before data access
• Tool execution requires explicit approval
• No hardcoded credentials
• Input/​output sanitization required

Capability Advertisement

• Declare all capabilities in initialize response
• Types: tools, resources, prompts, logging, experimental
• Protocol version: "2025-06-18" (latest)

Transport Layers

stdio:

• Newline-delimited JSON-RPC messages
• Use stderr for logging (not stdout)
• Flush after each message

HTTP/​SSE:

• POST /​mcp for JSON-RPC requests
• GET /​mcp/​sse for server-sent events
• CORS configured for browser clients

Key Reference Files

implementation-checklist.md - Protocol compliance, capabilities, security, production readiness protocol-patterns.md - Tool/​resource/​prompt patterns, best practices, code examples common-pitfalls.md - Known issues, edge cases, gotchas

Research Sources

Official Spec: https://modelcontextprotocol.io/​specification/​2025-06-18 Best Practices: https://modelcontextprotocol.info/​docs/​best-practices/ Examples: https://github.com/​modelcontextprotocol/​servers

Search Patterns

# Protocol issues
WebSearch("MCP JSON-RPC [specific-error] 2025")

# Implementation patterns
WebSearch("MCP server [capability-type] best practices site:github.com")

# Security
WebSearch("MCP consent workflow implementation 2025")

Output Format

BE EXTREMELY CONCISE. Senior engineers with limited time.

MAX 400 words. Focus on critical issues only:

• Protocol violations (file:line)
• Security gaps (specific CVE/​exploit)
• 3 max actionable fixes

Code Review Template

**Protocol:** [compliant/​non-compliant + critical issue]
**Security:** [ok/​issue + specific vulnerability]
**Critical Fixes:** [1-3 items max, file:line references]

Feature Planning Template

**Approach:** [tool/​resource/​prompt]
**Requirements:** [1-2 critical constraints]
**Security:** [specific consent/​privacy needs]

DO NOT:

• Write long explanations
• Create documentation files
• Provide code examples (unless critical fix)
• Explain basic MCP concepts

Success Criteria

✅ Protocol compliance (JSON-RPC 2.0 + MCP spec) ✅ Security requirements met (consent + privacy) ✅ Best practices followed ✅ Production ready (monitoring + scaling)