Documentation
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Overview ¶
Package mcp implements the slice of the Model Context Protocol that the intercom shim needs:
- Stdio transport (newline-delimited JSON-RPC 2.0)
- The initialize / notifications/initialized handshake
- tools/list and tools/call dispatch
- Public Notify(method, params) for sending arbitrary outbound notifications
The package keeps non-standard outbound notifications explicit because the shim emits notifications/claude/channel events.
This is not a full MCP implementation. It serves one well-defined client (Claude Code) over one transport (stdio).
Index ¶
Constants ¶
const LatestProtocolVersion = "2025-11-25"
LatestProtocolVersion is the MCP protocol version this implementation targets. We echo the client's version when accepting initialize, falling back to this constant if the client is unspecified.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Implementation ¶
Implementation describes the server (or client) at a high level. Sent in the initialize result's serverInfo field.
type Options ¶
type Options struct {
// Instructions is added to the initialize result. Claude Code includes
// this in the model's system prompt.
Instructions string
// Experimental populates capabilities.experimental verbatim. The intercom
// shim sets this to {"claude/channel": {}}.
Experimental map[string]any
}
Options configures a Server. All fields are optional.
type Server ¶
type Server struct {
// contains filtered or unexported fields
}
Server is a stdio-based MCP server. Construct with NewServer, register tools with RegisterTool, then run with Run.
func NewServer ¶
func NewServer(impl Implementation, opts Options) *Server
NewServer constructs a Server. The server does no I/O until Run is called.
func (*Server) Initialized ¶
func (s *Server) Initialized() <-chan struct{}
Initialized returns a channel closed after the client has completed the initialize/initialized handshake. Callers may want to wait on this before emitting their first Notify.
func (*Server) Notify ¶
Notify sends a JSON-RPC notification with the given method and params. Goroutine-safe. Returns an error only if marshaling or stdout write fails.
func (*Server) RegisterTool ¶
RegisterTool adds a tool. Must be called before Run; tool registration is not safe to mutate while the server is serving (and the spec requires sending listChanged, which we don't implement).
type Tool ¶
type Tool struct {
Name string
Description string
// InputSchema is a raw JSON object describing the tool's parameters as
// JSON Schema. Stored raw so callers can author it inline without paying
// a reflective inference dependency.
InputSchema json.RawMessage
Handler ToolHandler
}
Tool is a single registered MCP tool.
type ToolHandler ¶
type ToolHandler func(ctx context.Context, args json.RawMessage) (ToolResult, error)
ToolHandler implements a registered tool. It is invoked once per tools/call request and may run concurrently with other tool calls.
Return a non-nil error only for protocol-level failures (e.g. malformed arguments that bypass the schema, internal panics). For user-facing errors — "no such peer", "broker disconnected" — return a ToolResult with IsError=true; that surfaces in Claude's context as part of the tool output rather than as an MCP error response.
type ToolResult ¶
ToolResult is what a tool handler returns: a text payload and whether to flag it as an error to the caller. Maps to MCP's CallToolResult.
Source Files