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MCP Cheat Sheet

A quick reference for the Model Context Protocol: what it is, how it works, and why it matters for AI-assisted QA workflows.

Host / client / server Tools and resources stdio and HTTP

MCP in One Sentence

MCP gives AI applications a standard way to connect to tools, files, and services.

AI host -> MCP client -> MCP server -> tools / data

The Three Roles

These roles appear in nearly every MCP explanation and setup flow.

Host: the AI app
Client: protocol handler inside the host
Server: exposes tools, resources, prompts

Tool Call Flow

This is the practical sequence behind “AI using tools.”

1. Client asks server what tools exist
2. Model chooses a tool
3. Client sends tool call with arguments
4. Server executes
5. Result is returned to the host

Common MCP Concepts

These are the building blocks students should remember.

Tool:
A callable capability like browser_click

Resource:
Data the server can expose

Prompt:
A reusable template supplied by the server

Transports

Different environments use different transport styles.

stdio:
- local child process
- common for desktop tools

HTTP/SSE:
- remote service
- useful for shared or hosted tools

QA Use Cases

MCP is especially powerful when AI needs structured access to testing systems.

- browser automation
- code review helpers
- Jira integration
- file system exploration
- CI failure diagnosis
- report generation

Tool Schema Mindset

Each tool should be clear, constrained, and easy for the model to call correctly.

Good tool schema:
- strong name
- clear description
- typed arguments
- safe behavior
- predictable return shape

Security

Tool access should be deliberate, not open-ended.

- use least privilege
- review write access carefully
- avoid exposing secrets
- keep auditability where possible
- prefer read-only tools unless writes are required

MCP vs Ad-hoc Integrations

The benefit is standardization, not magic.

Without MCP:
- custom integration per tool

With MCP:
- one protocol
- discoverable tools
- shared structure
- easier multi-tool orchestration