hooks

Documentation

Overview

Package hooks defines types and interfaces for the gomcp hooks system, allowing users to inject custom logic at various points in the client and server lifecycles.

Index

• type AfterToolCallHook
• type BeforeHandleMessageHook
• type BeforeSendResponseHook
• type BeforeSessionDestroyHook
• type BeforeToolCallHook
• type BeforeUnmarshalHook
• type ClientBeforeHandleNotificationHook
• type ClientBeforeHandleRequestHook
• type ClientBeforeHandleResponseHook
• type ClientBeforeSendNotificationHook
• type ClientBeforeSendRequestHook
• type ClientHookContext
• type FinalToolHandler
• type OnReceiveRawMessageHook
• type OnSessionCreateHook
• type ServerBeforeHandleNotificationHook
• type ServerBeforeHandleRequestHook
• type ServerBeforeSendNotificationHook
• type ServerHookContext

Types

type AfterToolCallHook

type AfterToolCallHook func(hookCtx ServerHookContext, arguments any, content []protocol.Content, isError bool, toolErr error) (modifiedContent []protocol.Content, modifiedIsError bool, modifiedError error)

AfterToolCallHook: Runs after a tool handler executes. Accesses ToolDefinition via hookCtx. Return: Modified content, isError flag, error.

type BeforeHandleMessageHook

type BeforeHandleMessageHook func(ctx context.Context, session types.ClientSession, rawMessage []byte) (modifiedRawMessage []byte, err error)

BeforeHandleMessageHook: Runs after receiving raw bytes, before any JSON parsing. Return: Modified bytes (if changed), error to stop processing.

type BeforeSendResponseHook

type BeforeSendResponseHook func(hookCtx ServerHookContext, response *protocol.JSONRPCResponse) (modifiedResponse *protocol.JSONRPCResponse, err error)

BeforeSendResponseHook: Runs before a response is sent back to the client. Return: Modified response object, error to prevent sending.

type BeforeSessionDestroyHook

type BeforeSessionDestroyHook func(hookCtx ServerHookContext) error

BeforeSessionDestroyHook: Runs just before a session is unregistered.

type BeforeToolCallHook

type BeforeToolCallHook func(next FinalToolHandler) FinalToolHandler

BeforeToolCallHook wraps the next handler in the chain, allowing modification before execution. It receives the next handler (which could be another hook wrapper or the final handler) and returns a new handler function that incorporates the hook's logic.

type BeforeUnmarshalHook

type BeforeUnmarshalHook func(hookCtx ServerHookContext, rawParams json.RawMessage) error

BeforeUnmarshalHook: Runs after basic JSON structure detected but before specific unmarshalling. Return: Error to stop processing.

type ClientBeforeHandleNotificationHook

type ClientBeforeHandleNotificationHook func(hookCtx ClientHookContext, method string, params any) error

ClientBeforeHandleNotificationHook: Runs after parsing an incoming notification on the client, before calling registered handler. Params: Parsed params (`any`). Return: Error to prevent calling handler.

type ClientBeforeHandleRequestHook

type ClientBeforeHandleRequestHook func(hookCtx ClientHookContext, id interface{}, method string, params any) error

ClientBeforeHandleRequestHook: Runs after parsing an incoming server-to-client request on the client, before calling handler. Params: Parsed params (`any`). Return: Error to prevent calling handler (and send error response).

type ClientBeforeHandleResponseHook

type ClientBeforeHandleResponseHook func(hookCtx ClientHookContext, response *protocol.JSONRPCResponse) (modifiedResponse *protocol.JSONRPCResponse, err error)

ClientBeforeHandleResponseHook: Runs after parsing a response, before matching to pending request. Return: Modified response object, error to stop processing.

type ClientBeforeSendNotificationHook

type ClientBeforeSendNotificationHook func(hookCtx ClientHookContext, notification *protocol.JSONRPCNotification) (modifiedNotification *protocol.JSONRPCNotification, err error)

ClientBeforeSendNotificationHook: Runs before marshalling and sending a client notification. Return: Modified notification object, error to prevent sending.

type ClientBeforeSendRequestHook

type ClientBeforeSendRequestHook func(hookCtx ClientHookContext, request *protocol.JSONRPCRequest) (modifiedRequest *protocol.JSONRPCRequest, err error)

ClientBeforeSendRequestHook: Runs before marshalling and sending a client request. Return: Modified request object, error to prevent sending.

type ClientHookContext

type ClientHookContext struct {
	Ctx               context.Context
	ClientInfo        protocol.Implementation // Info about this client instance
	NegotiatedVersion string
	ServerInfo        protocol.Implementation // Info about the connected server
	ServerCaps        protocol.ServerCapabilities
	MessageID         interface{} // nil for notifications/incoming requests
	Method            string      // Can be empty for responses
}

ClientHookContext provides context for client-side hooks.

type FinalToolHandler

type FinalToolHandler func(ctx context.Context, progressToken interface{}, arguments any) (content []protocol.Content, isError bool)

FinalToolHandler defines the signature for the actual tool execution logic.

type OnReceiveRawMessageHook

type OnReceiveRawMessageHook func(hookCtx ClientHookContext, rawMessage []byte) (modifiedRawMessage []byte, err error)

OnReceiveRawMessageHook: Runs after receiving raw bytes from transport, before parsing. Return: Modified bytes, error to stop processing.

type OnSessionCreateHook

type OnSessionCreateHook func(hookCtx ServerHookContext) error

OnSessionCreateHook: Runs after a new session is successfully registered.

type ServerBeforeHandleNotificationHook

type ServerBeforeHandleNotificationHook func(hookCtx ServerHookContext, params any) error

ServerBeforeHandleNotificationHook: Runs before routing a parsed notification on the server. Params: Parsed params (`any`). Return: Error to stop processing.

type ServerBeforeHandleRequestHook

type ServerBeforeHandleRequestHook func(hookCtx ServerHookContext, params any) error

ServerBeforeHandleRequestHook: Runs before routing a parsed request to its specific handler on the server. Params: Parsed params (`any`). Return: Error to stop processing (e.g., return auth error response).

type ServerBeforeSendNotificationHook

type ServerBeforeSendNotificationHook func(hookCtx ServerHookContext, method string, params any) (modifiedMethod string, modifiedParams any, err error)

ServerBeforeSendNotificationHook: Runs before a server-initiated notification is sent. Return: Modified method/params, error to prevent sending.

type ServerHookContext

type ServerHookContext struct {
	Ctx            context.Context
	Session        types.ClientSession // Interface to interact with the specific client session
	MessageID      interface{}         // nil for notifications
	Method         string              // Method name if applicable
	ToolDefinition *protocol.Tool      // Populated for tool-related hooks
}

ServerHookContext provides context available to most server-side hooks.