MCP Servers Explained: Model Context Protocol with Claude

Anthropic launched Model Context Protocol (MCP) today. It's the extension system that turns Claude Code from a standalone app into a platform that connects to your tools and data.

If you've wished Claude could access your database, read from your CRM, or integrate with your company's internal APIs, MCP makes that possible.

## What MCP Is

Model Context Protocol is a standard way for Claude to connect to external data sources and tools.

Think of MCP servers as plugins or extensions. Each MCP server gives Claude access to a specific tool or data source:

- **Database MCP server:** Query your PostgreSQL, MySQL, or MongoDB directly from Claude
- **GitHub MCP server:** Read repositories, issues, and pull requests without leaving Claude
- **Slack MCP server:** Search message history, read channels, understand team context
- **Google Drive MCP server:** Access documents, sheets, and slides from company drives

Each MCP server is a small program that runs on your machine and translates between Claude and external tools.

## How MCP Servers Work

The technical flow:

1. You configure MCP servers in Claude Code's settings (JSON config file)
2. When you start Claude Code, it launches the configured MCP servers
3. During conversations, Claude can request data from MCP servers
4. MCP servers fetch the data and return it to Claude
5. Claude uses that data to answer your questions or complete tasks

**Example conversation:**

You: "What were the three most discussed topics in our #engineering Slack channel last week?"

Claude (via Slack MCP server):
1. Fetches messages from #engineering for the past 7 days
2. Analyzes conversation threads
3. Identifies top topics: database migration (45 messages), API redesign (32 messages), deployment issues (28 messages)
4. Returns summary with links to key threads

All of this happens in one conversation, with Claude accessing Slack through the MCP server.

## Why This Matters

Before MCP, Claude was isolated. It knew nothing about your company's data, tools, or context. Every conversation started from zero.

You'd copy data from Slack, paste into Claude, copy results, paste back into Slack. This copy-paste workflow limited Claude's usefulness for real work.

**With MCP:**
- Claude accesses your company's data directly
- No more copy-paste between tools
- Context from multiple sources in one conversation
- Claude becomes part of your workflow instead of a separate tool

## What MCP Servers Can Do

MCP servers fall into three categories:

**Data Access:**
Let Claude read from databases, APIs, file systems, or cloud storage.

Examples:
- Query customer data from your database
- Read analytics from your BI platform
- Access documents from Google Drive or SharePoint
- Fetch tickets from Jira or Linear

**Tool Integration:**
Let Claude interact with external tools and services.

Examples:
- Search Slack or Discord message history
- Read GitHub repositories and issues
- Query internal wikis or documentation
- Access CRM data from Salesforce or HubSpot

**System Operations:**
Let Claude interact with your local environment.

Examples:
- Read and write local files with better permissions
- Execute shell commands with approval
- Access environment variables and configs
- Monitor system resources and logs

## Available MCP Servers at Launch

Anthropic is launching with several official MCP servers:

**Database Servers:**
- PostgreSQL MCP server
- SQLite MCP server
- MySQL/MariaDB MCP server (community-built)

**Development Tools:**
- GitHub MCP server (official)
- Git MCP server for local repositories
- Docker MCP server for container management

**Business Tools:**
- Slack MCP server
- Google Drive MCP server (read-only at launch)
- Notion MCP server (community-built)

**System Tools:**
- Filesystem MCP server (extended file access)
- Environment MCP server (env vars and configs)
- Shell MCP server (command execution with prompts)

More servers coming from both Anthropic and the community. The protocol is open source, so anyone can build MCP servers.

## Security and Permissions

MCP servers run on your machine with your permissions. This means:

**What MCP servers can access:**
Anything you can access. If you can read a database, the MCP server can read it. If you can't access a Slack workspace, the MCP server can't either.

**Security model:**
- MCP servers run locally, not in the cloud
- Each server explicitly declares what permissions it needs
- You approve permissions before using a server
- Claude requests data from servers; servers don't push data to Claude

**Best practices:**
- Only install MCP servers from trusted sources
- Review what permissions each server requests
- Use read-only access when possible
- Don't install MCP servers for sensitive systems without security review

## Limitations

MCP is new. Current limitations:

**Claude Code only:**
MCP servers only work in Claude Code (the desktop app). The web interface at claude.ai doesn't support MCP.

**No write operations (yet):**
Most launch MCP servers are read-only. Claude can query databases but not modify them. This limitation is intentional for safety and will be relaxed over time.

**Performance:**
Complex queries can be slow. If an MCP server needs to fetch large datasets or make multiple API calls, conversations slow down.

**Configuration required:**
Setting up MCP servers requires editing JSON config files. Not difficult, but not as simple as clicking "install" in an app store.

## Quick Takeaway

MCP (Model Context Protocol) is the extension system for Claude Code. MCP servers let Claude access databases, APIs, and external tools directly - no more copy-paste workflows.

At launch, official servers cover databases (PostgreSQL, SQLite), development tools (GitHub, Git), business apps (Slack, Google Drive), and system operations (filesystem, shell access).

If you use Claude Code for work that involves company data or external tools, MCP immediately makes it more useful. Start with the official servers, then explore community-built options.

The protocol is open source, so expect the MCP ecosystem to grow quickly. This is the foundation for making Claude a true part of your technical workflow.