MCP Server Development

researched 2026-05-25· 7 sources · 10 concepts · skill mcp-servers

MCP uses JSON-RPC 2.0 with a three-layer model: Host (AI application) → Client (stateful session manager) → Server (exposes tools, resources, prompts).

Architecture

MCP uses JSON-RPC 2.0 with a three-layer model: Host (AI application) → Client (stateful session manager) → Server (exposes tools, resources, prompts). [source]

stdio

Communication via stdin/stdout of a child process [source]
Zero network overhead, inherently single-client [source]
Default for local developer tools and desktop integrations [source]

Streamable HTTP (introduced March 2026, replaces deprecated SSE)

POST for client→server requests [source]
GET for SSE notifications (server→client) [source]
DELETE to terminate sessions [source]

Security: OAuth 2.1 + PKCE

Mandatory for public remote MCP servers since November 2025. [source]
Resource indicators (RFC 8707): bind tokens to one server - blocks cross-server replay [source]
Refresh rotation: for public clients, rotate refresh tokens on each use [source]
NEVER forward client tokens to backend services [source]

Best practices checklist

[ ] Zod/Pydantic input validation - never trust raw LLM arguments [source]
[ ] Health checks for production deployments [source]
[ ] OAuth 2.1 + PKCE for any public-facing remote server [source]
[ ] Streamable HTTP (not deprecated SSE) for all new remote servers [source]
[ ] Structured logging and telemetry for production observability [source]

Children

MCP Server Builder Patterns
JSON-RPC 2.0 Architecture (frontier)
MCP OAuth 2.1 Security (frontier)
Sampling and Elicitation (frontier)
MCP Deployment (frontier)

Frontier under this node: JSON-RPC 2.0 Architecture, MCP Deployment, MCP OAuth 2.1 Security, Sampling and Elicitation

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