OpenCode MCP Explained

The Model Context Protocol (MCP) is a standard that allows AI models to interact with external data and tools relative to the user's context. OpenCode is built as an MCP-native client, meaning it can consume any standardized MCP server.

What is MCP?

Think of MCP as "USB for AI".

• Before MCP: Every AI tool had to build custom integrations (GitHub, Postgres, Slack types).
• With MCP: You run a "server" that exposes data, and any "client" (like OpenCode or Claude) can use it.

Using MCP with OpenCode

OpenCode reads your MCP configuration to know what tools are available to the agent.

1. Configuration (mcp_config.json)

OpenCode looks for standard MCP configuration files. You can define servers that run locally using npx or docker.

{
  "mcpServers": {
    "git": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-git", "."]
    },
    "postgres": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-postgres", "postgresql://user:password@localhost/db"]
    }
  }
}

2. Available Servers

Because OpenCode uses the standard, you can use any server from the official list:

• Filesystem: Allow safe access to specific directories.
• Git: Let the agent read diffs and commit history.
• Postgres: Let the agent query DB schemas to write better SQL.
• Slack: Let the agent summarize channel discussions.

3. Granting Permissions

OpenCode is security-first. When an agent tries to use an MCP tool (e.g., postgres.execute_query), the CLI will pause and ask for your permission unless you have run with --auto-approve.

[Agent] Wants to run tool: git_commit
[Y/n] ?

Creating Your Own MCP Server

You can extend OpenCode by writing a simple MCP server in TypeScript or Python.

Example: A "Time" Server If simple LLMs forget the date, you can expose a tool get_current_time. The agent will see this in its context window and call it when asked "How many days until Christmas?".

Why OpenCode + MCP is Powerful

Unlike cloud-based agents where connecting your local database API is a firewall nightmare, OpenCode runs locally on your network.

• Connect to localhost:5432 easily.
• Read internal wiki docs behind VPN using a fetch MCP server.

This makes OpenCode the ideal orchestrator for enterprise intranets.

Next Steps

• Learn about CLI Commands to manage servers.
• See Use Cases for examples of MCP in action (e.g., "Chat with my Database").