---
title: internal/mcp
description: Go API reference for the mcp package.
---

<!-- Code generated by gomarkdoc. DO NOT EDIT -->

# mcp

```go
import "github.com/jbcom/radioactive-ralph/internal/mcp"
```

Package mcp wraps modelcontextprotocol/go\-sdk to expose Ralph's plan\-DAG and variant\-pool surface as MCP tools. Claude Code talks to the binary through this server over stdio; the binary remains the durable product surface and MCP is the structured control plane.

## Index

- [type Options](<#Options>)
- [type Server](<#Server>)
  - [func New\(o Options\) \(\*Server, error\)](<#New>)
  - [func \(s \*Server\) MCPServer\(\) \*mcpsdk.Server](<#Server.MCPServer>)
  - [func \(s \*Server\) ServeStdio\(ctx context.Context\) error](<#Server.ServeStdio>)


<a name="Options"></a>
## type [Options](<https://github.com/jbcom/radioactive-ralph/blob/main/internal/mcp/server.go#L19-L33>)

Options configures Server creation.

```go
type Options struct {
    // Store is the plandag handle backing every plan.* tool.
    Store *plandag.Store

    // Pool is the variantpool handle backing every variant.* tool.
    Pool *variantpool.Pool

    // SessionID is the plandag session this server runs under. Both
    // the plandag CRUD tools and the variantpool tools are scoped
    // to this session.
    SessionID string

    // ServerInfo identifies us in the MCP handshake.
    ServerInfo *mcpsdk.Implementation
}
```

<a name="Server"></a>
## type [Server](<https://github.com/jbcom/radioactive-ralph/blob/main/internal/mcp/server.go#L36-L39>)

Server bundles the registered MCP server with its options.

```go
type Server struct {
    // contains filtered or unexported fields
}
```

<a name="New"></a>
### func [New](<https://github.com/jbcom/radioactive-ralph/blob/main/internal/mcp/server.go#L42>)

```go
func New(o Options) (*Server, error)
```

New builds an MCP server with every Ralph tool registered.

<a name="Server.MCPServer"></a>
### func \(\*Server\) [MCPServer](<https://github.com/jbcom/radioactive-ralph/blob/main/internal/mcp/server.go#L67>)

```go
func (s *Server) MCPServer() *mcpsdk.Server
```

MCPServer returns the underlying SDK server. Useful for tests that drive the server via in\-memory transports.

<a name="Server.ServeStdio"></a>
### func \(\*Server\) [ServeStdio](<https://github.com/jbcom/radioactive-ralph/blob/main/internal/mcp/stdio.go#L15>)

```go
func (s *Server) ServeStdio(ctx context.Context) error
```

ServeStdio runs the MCP server over the stdio transport. Blocks until the client closes the connection or ctx is canceled.

Used by the portable mode CLI \(\`radioactive\_ralph serve \-\-mcp\`\). One process = one MCP session; the spawning Claude session owns the lifetime.

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