# The MCP Protocol: A Standard Interface for Agent Tool Chains

What MCP Solves

Agents need tools — filesystems, databases, browsers, APIs — but every agent framework kept reinventing the wheel. MCP provides a unified tool-interface protocol:

Agent ←→ MCP Client ←→ MCP Server ←→ Real tools

Core Design

Concept	Meaning
Tools	Functions the agent can call (visible to the model)
Resources	Context data the agent can read
Prompts	Predefined conversation templates
Transports	stdio or HTTP/SSE connections

Production Practices

1. Never install too many: adding 50 MCP servers won’t make the agent stronger — it just splits its attention
2. The tool description is the prompt: the agent decides when to call a tool based on its description, so write it precisely
3. The permission boundary lives at the server layer: the sandbox isn’t your only line of defense
4. Failure is normal: tool calls can fail — design for retries and graceful degradation

References

• Anthropic MCP Specification
• awesome-mcp-servers (mcpservers.org)
• Practical notes from WebdriverIO + Selenium MCP Server usage