mcp

Documentation

Overview

Package mcp provides MCP (Model Context Protocol) client support. MCP allows connecting to external tool servers.

Package mcp provides MCP (Model Context Protocol) client support.

Index

• type Client
  • func NewClient(config ServerConfig) (*Client, error)
  • func (c *Client) CallTool(ctx context.Context, name string, args map[string]interface{}) (*ToolCallResult, error)
  • func (c *Client) Close() error
  • func (c *Client) Initialize(ctx context.Context) error
  • func (c *Client) ListTools(ctx context.Context) ([]Tool, error)
  • func (c *Client) Tools() []Tool
• type Content
• type Manager
  • func NewManager() *Manager
  • func (m *Manager) AllTools() []ToolWithServer
  • func (m *Manager) CallTool(ctx context.Context, server, tool string, args map[string]interface{}) (*ToolCallResult, error)
  • func (m *Manager) Close() error
  • func (m *Manager) Connect(ctx context.Context, name string, config ServerConfig) error
  • func (m *Manager) Disconnect(name string) error
  • func (m *Manager) FindTool(name string) (server string, found bool)
  • func (m *Manager) ServerCount() int
  • func (m *Manager) Servers() []string
  • func (m *Manager) SetDeniedTools(server string, tools []string)
• type RPCError
  • func (e *RPCError) Error() string
• type Request
• type Response
• type ServerConfig
• type Tool
• type ToolCallParams
• type ToolCallResult
• type ToolWithServer
• type ToolsListResult

Types

type Client

type Client struct {
	// contains filtered or unexported fields
}

Client is an MCP client that connects to tool servers.

func NewClient

func NewClient(config ServerConfig) (*Client, error)

NewClient creates a new MCP client for a server.

func (*Client) CallTool

func (c *Client) CallTool(ctx context.Context, name string, args map[string]interface{}) (*ToolCallResult, error)

CallTool invokes a tool on the server.

func (*Client) Close

func (c *Client) Close() error

Close shuts down the MCP server.

func (*Client) Initialize

func (c *Client) Initialize(ctx context.Context) error

Initialize performs the MCP initialization handshake.

func (*Client) ListTools

func (c *Client) ListTools(ctx context.Context) ([]Tool, error)

ListTools fetches available tools from the server.

func (*Client) Tools

func (c *Client) Tools() []Tool

Tools returns cached tools.

type Content

type Content struct {
	Type string `json:"type"`
	Text string `json:"text,omitempty"`
	Data string `json:"data,omitempty"` // base64 for images
}

Content represents content in a tool result.

type Manager

type Manager struct {
	// contains filtered or unexported fields
}

Manager manages multiple MCP server connections.

func NewManager

func NewManager() *Manager

NewManager creates a new MCP manager.

func (*Manager) AllTools

func (m *Manager) AllTools() []ToolWithServer

AllTools returns all tools from all connected servers, excluding denied tools.

func (*Manager) CallTool

func (m *Manager) CallTool(ctx context.Context, server, tool string, args map[string]interface{}) (*ToolCallResult, error)

CallTool calls a tool on a specific server.

func (*Manager) Close

func (m *Manager) Close() error

Close disconnects all servers.

func (*Manager) Connect

func (m *Manager) Connect(ctx context.Context, name string, config ServerConfig) error

Connect connects to an MCP server.

func (*Manager) Disconnect

func (m *Manager) Disconnect(name string) error

Disconnect disconnects from an MCP server.

func (*Manager) FindTool

func (m *Manager) FindTool(name string) (server string, found bool)

FindTool finds which server has a tool, excluding denied tools.

func (*Manager) ServerCount

func (m *Manager) ServerCount() int

ServerCount returns the number of connected servers.

func (*Manager) Servers

func (m *Manager) Servers() []string

Servers returns the names of connected servers.

func (*Manager) SetDeniedTools

func (m *Manager) SetDeniedTools(server string, tools []string)

SetDeniedTools sets tools to exclude from a server's tool list. These tools will not be returned by AllTools() and won't be exposed to the LLM.

type RPCError

type RPCError struct {
	Code    int    `json:"code"`
	Message string `json:"message"`
}

RPCError represents a JSON-RPC error.

func (*RPCError) Error

func (e *RPCError) Error() string

type Request

type Request struct {
	JSONRPC string      `json:"jsonrpc"`
	ID      int64       `json:"id"`
	Method  string      `json:"method"`
	Params  interface{} `json:"params,omitempty"`
}

Request is a JSON-RPC 2.0 request.

type Response

type Response struct {
	JSONRPC string          `json:"jsonrpc"`
	ID      int64           `json:"id"`
	Result  json.RawMessage `json:"result,omitempty"`
	Error   *RPCError       `json:"error,omitempty"`
}

Response is a JSON-RPC 2.0 response.

type ServerConfig

type ServerConfig struct {
	Command string            `json:"command"`
	Args    []string          `json:"args,omitempty"`
	Env     map[string]string `json:"env,omitempty"`
}

ServerConfig configures an MCP server connection.

type Tool

type Tool struct {
	Name        string                 `json:"name"`
	Description string                 `json:"description"`
	InputSchema map[string]interface{} `json:"inputSchema"`
}

Tool represents an MCP tool definition.

type ToolCallParams

type ToolCallParams struct {
	Name      string                 `json:"name"`
	Arguments map[string]interface{} `json:"arguments,omitempty"`
}

ToolCallParams are the parameters for tools/call.

type ToolCallResult

type ToolCallResult struct {
	Content []Content `json:"content"`
	IsError bool      `json:"isError"`
}

ToolCallResult is the result of tools/call.

type ToolWithServer

type ToolWithServer struct {
	Server string
	Tool   Tool
}

ToolWithServer pairs a tool with its server name.

type ToolsListResult

type ToolsListResult struct {
	Tools []Tool `json:"tools"`
}

ToolsListResult is the result of tools/list.