MCP
The Model Context Protocol connects external capabilities such as browsers, databases, and docs search to any AI tool that supports it, through one interface.
- Last reviewed
- Website
- modelcontextprotocol.io
Good for
- Letting the agent do what it otherwise cannot: drive a browser, query a database, read designs or tickets
- External capabilities you want to set up once and share across tools
- Cases that need live data (current docs, production status) rather than model memory
Not for
- Telling the agent your project conventions (use AGENTS.md)
- A fixed sequence of steps (use Skills, which are lighter)
- Third-party servers of unknown origin: the model reads their tool descriptions and results
MCP (Model Context Protocol) is an open protocol based on JSON-RPC. Anthropic released it in November 2024 and donated it to the Agentic AI Foundation under the Linux Foundation in December 2025. It defines how an AI application (the host) connects to external MCP servers.
A server can offer three things
- Tools: operations the model can call, such as "open a page and take a screenshot" or "run a query".
- Resources: data that can be read, such as files, schemas, or recent tickets.
- Prompts: parameterized templates the user can invoke like commands.
Write an MCP server once, and Cursor, Claude Code, and any other MCP-capable tool can use it.
When it is worth connecting
Ask yourself: is the agent failing because it does not know something, or because it cannot do something? If it does not know your conventions, write AGENTS.md. Only when it cannot act (for example, it cannot open a browser to check a page) should you add MCP. For frontend work the most useful one is browser automation: the agent opens the page, clicks, takes screenshots, and verifies that a change really works.
Security
An MCP server's tool descriptions and results go into the model's context, and the model may follow instructions hidden in them. Install only servers you trust, and keep human confirmation before tools that write (sending messages, changing data).
Configuration
Most tools declare servers in a JSON file with the same basic shape: each entry under mcpServers gives a command and its arguments. Cursor reads .cursor/mcp.json in the project; Claude Code reads .mcp.json in the project root. The souvenir below configures Playwright's browser automation server; put it where your tool expects it.
Take it home to your AI
Drop this mcp.json into your project, or paste it straight to your AI coding assistant.
{
"mcpServers": {
"playwright": {
"command": "npx",
"args": ["@playwright/mcp@latest"]
}
}
}
Related
- Article
The pieces of context you give AI
AGENTS.md sets project rules, Rules handle local scope, MCP adds external capabilities, and Skills hold know-how loaded on demand.
- Entry
Skills
Package how to do a kind of task as a folder. The agent remembers only its name and description until a task calls for the full text.
- EntryTop pick
Cursor
An AI IDE built on VS Code. Completion, chat, the agent, and your code live in one window, and every change arrives as a diff.