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client

package
v1.9.0 Latest Latest
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 Go to latest Published: Oct 21, 2026 License: MIT Imports: 15 Imported by: 0

Documentation

Index

Constants

View Source 
const (
	ToolsListChanged     = "notifications/tools/list_changed"
	PromptsListChanged   = "notifications/prompts/list_changed"
	ResourcesListChanged = "notifications/resources/list_changed"
	ResourceUpdated      = "notifications/resources/updated"
)

Notification methods a client receives via subscriptions/listen.

View Source 
const StatelessRevision = "2026-07-28"

StatelessRevision is the first protocol revision without initialize, ping and logging/setLevel (SEP-2575); the handshake is server/discover.

View Source 
const TasksExtension = "io.modelcontextprotocol/tasks"

TasksExtension identifies the Tasks extension (spec 2026-07-28).

Variables

View Source 
var NotificationMethods = []string{ToolsListChanged, PromptsListChanged, ResourcesListChanged, ResourceUpdated}

NotificationMethods are the methods Notifications can wait for.

Functions

func CallRaw added in v1.4.0 

func CallRaw(ctx context.Context, session *mcp.ClientSession, method string, params any) (map[string]any, error)

CallRaw sends any request on the session's connection and returns the raw result. Nothing is added to params, not even the per-request metadata.

func CallRawJSON added in v1.9.0 

func CallRawJSON(ctx context.Context, session *mcp.ClientSession, method string, params any) (json.RawMessage, error)

CallRawJSON is CallRaw returning the result exactly as it came over the wire, which keeps the key order of objects that a map would lose.

func CallToolRaw 

func CallToolRaw(ctx context.Context, session *mcp.ClientSession, toolName string, arguments any, meta map[string]any) (map[string]any, error)

CallToolRaw performs a tool call and returns the raw map[string]any result, bypassing the strict SDK unmarshaling that fails on missing "type" fields.

func Complete added in v1.4.0 

func Complete(ctx context.Context, session *mcp.ClientSession, ref, arg, value string, contextArgs map[string]string) (*mcp.CompleteResult, error)

Complete asks the server for completion candidates of one argument. contextArgs are previously resolved arguments; nil if there are none.

func IsStateless added in v1.4.0 

func IsStateless(session *mcp.ClientSession) bool

IsStateless reports whether the session negotiated StatelessRevision or later.

func ListAllPrompts added in v1.4.0 

func ListAllPrompts(ctx context.Context, session *mcp.ClientSession) ([]*mcp.Prompt, error)

ListAllPrompts follows nextCursor through every page of prompts/list.

func ListAllResources added in v1.4.0 

func ListAllResources(ctx context.Context, session *mcp.ClientSession) ([]*mcp.Resource, error)

ListAllResources follows nextCursor through every page of resources/list.

func ListAllTools added in v1.4.0 

func ListAllTools(ctx context.Context, session *mcp.ClientSession) ([]*mcp.Tool, error)

ListAllTools follows nextCursor through every page of tools/list. A single ListTools call returns only the first page, so servers that paginate would seem to have fewer tools.

func ParseCompleteRef added in v1.4.0 

func ParseCompleteRef(ref string) (*mcp.CompleteReference, error)

ParseCompleteRef turns "prompt:<name>" or "resource:<uri template>" into a completion reference.

func ParseElicitAnswer added in v1.4.0 

func ParseElicitAnswer(action, content string) (*mcp.ElicitResult, error)

ParseElicitAnswer turns "accept", "decline", "cancel" or "accept:<json>" and an optional separate JSON object into an elicitation result.

func Ping added in v1.4.0 

func Ping(ctx context.Context, session *mcp.ClientSession) (string, error)

Ping checks that the server answers and returns the method that proved it. Since 2026-07-28 ping is removed; the server/discover exchange that opened the session is the liveness check then.

func RequestMeta added in v1.4.0 

func RequestMeta(session *mcp.ClientSession, capabilities map[string]any) map[string]any

RequestMeta is the per-request metadata (2026-07-28) for requests sent over the raw path, which the SDK does not fill in: protocol version, client info and the given client capabilities (nil means none).

func TaskResult added in v1.4.0 

func TaskResult(task map[string]any) (map[string]any, error)

TaskResult returns the final tool result of a completed task, or an error for a failed or cancelled one.

func WithLogLevel added in v1.4.0 

func WithLogLevel(meta mcp.Meta, level string) mcp.Meta

WithLogLevel adds the per-request log level (2026-07-28) to meta.

Types

type DeprecationWatch added in v1.6.1 

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

DeprecationWatch notes the deprecated client features a server asks for: sampling and roots, deprecated since 2026-07-28 (SEP-2577).

It watches the wire, not the SDK: the SDK answers such requests inside its multi round-trip loop, behind any middleware. Answers travel in the inputResponses of the retried request, and multi round-trip only exists from 2026-07-28 on, so servers on older revisions — where both features are regular server-to-client requests — are not reported.

func (*DeprecationWatch) Used added in v1.6.1 

func (w *DeprecationWatch) Used() []string

Used lists the deprecated features seen so far, sorted.

func (*DeprecationWatch) Wrap added in v1.6.1 

func (w *DeprecationWatch) Wrap(t mcp.Transport) mcp.Transport

Wrap returns t with every outgoing request inspected.

type Notification added in v1.4.0 

type Notification struct {
	Method string
	URI    string // only for resources/updated
}

Notification is one received server notification.

type NotificationTap added in v1.8.0 

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

NotificationTap records server notifications the go-sdk does not know (notifications/tasks) or keeps to itself (notifications/subscriptions/ acknowledged), by reading the raw messages below the SDK. The messages are passed on unchanged.

func NewNotificationTap added in v1.8.0 

func NewNotificationTap(methods ...string) *NotificationTap

NewNotificationTap records notifications with one of the methods.

func (*NotificationTap) Received added in v1.8.0 

func (n *NotificationTap) Received(method string) []map[string]any

Received returns the notifications recorded so far with the method.

func (*NotificationTap) Wrap added in v1.8.0 

func (n *NotificationTap) Wrap(t mcp.Transport) mcp.Transport

Wrap returns t with the tap installed on its connections.

type Notifications added in v1.4.0 

type Notifications struct {
	// Out receives one line per notification.
	Out io.Writer
	// contains filtered or unexported fields
}

Notifications records list-changed and resource-updated notifications. Installing its handlers makes the SDK open a subscriptions/listen stream for every list the server marks as listChanged.

func (*Notifications) Install added in v1.4.0 

func (n *Notifications) Install(opts *mcp.ClientOptions)

Install sets the notification handlers on opts.

func (*Notifications) Wait added in v1.4.0 

func (n *Notifications) Wait(ctx context.Context, method, uri string, timeout time.Duration) error

Wait blocks until a notification with method (and uri, if not empty) arrives or timeout passes, and consumes it. Notifications received before the call count, so a wait after the triggering call cannot miss one.

type RPCError added in v0.2.1 

type RPCError struct {
	Code    int64
	Message string
	Data    any
}

RPCError representing a JSON-RPC error

func (*RPCError) Error added in v0.2.1 

func (e *RPCError) Error() string

type Responder added in v1.4.0 

type Responder struct {
	// Strict makes a request without a queued answer fail the call; otherwise
	// elicitations are declined and sampling fails with an explanation.
	Strict bool
	// Out receives one line per answered request.
	Out io.Writer
	// contains filtered or unexported fields
}

Responder answers the input a server asks the client for (elicitation and sampling, since 2026-07-28 via multi round-trip requests) from queued, prepared answers, and remembers the last request for assertions.

func (*Responder) Answer added in v1.4.0 

func (r *Responder) Answer(ctx context.Context, ir mcp.InputRequest, roots []*mcp.Root) (any, error)

Answer answers one input request that arrived outside the SDK's own multi round-trip handling, e.g. in a task's inputRequests. roots supplies the answer to roots/list.

func (*Responder) Install added in v1.4.0 

func (r *Responder) Install(opts *mcp.ClientOptions)

Install sets the handlers on opts and declares the matching capabilities: roots, elicitation in form and URL mode, and sampling.

func (*Responder) LastElicitMessage added in v1.4.0 

func (r *Responder) LastElicitMessage() string

LastElicitMessage returns the message of the last elicitation request, or "".

func (*Responder) LastSamplePrompt added in v1.4.0 

func (r *Responder) LastSamplePrompt() string

LastSamplePrompt returns the text of the last sampling request, or "".

func (*Responder) QueueElicit added in v1.4.0 

func (r *Responder) QueueElicit(res *mcp.ElicitResult)

QueueElicit adds an answer for the next elicitation request.

func (*Responder) QueueSample added in v1.4.0 

func (r *Responder) QueueSample(text string)

QueueSample adds the model reply for the next sampling request.

type TappedNotification added in v1.8.0 

type TappedNotification struct {
	Method string
	Params map[string]any
}

TappedNotification is one recorded notification.

type TaskClient added in v1.4.0 

type TaskClient struct {
	Session   *mcp.ClientSession
	Responder *Responder // answers the task's inputRequests
	//lint:ignore SA1019 roots are deprecated since 2026-07-28 (SEP-2577) but still used by servers and regular before; remove with T-20260927-05
	Roots []*mcp.Root
	Out   io.Writer // one line per status change; optional
	// contains filtered or unexported fields
}

TaskClient runs tool calls as tasks. The go-sdk client does not know the extension (it drops the task fields of a CreateTaskResult), so requests go over the raw connection with the per-request metadata built here.

func (*TaskClient) Answer added in v1.8.0 

func (c *TaskClient) Answer(ctx context.Context, taskID string, raw any, answered map[string]bool) error

Answer fulfills the not yet answered input requests of a task via tasks/update; answered carries the keys already answered across polls.

func (*TaskClient) Cancel added in v1.4.0 

func (c *TaskClient) Cancel(ctx context.Context, taskID string) error

Cancel asks the server to cancel a task (tasks/cancel).

func (*TaskClient) Get added in v1.4.0 

func (c *TaskClient) Get(ctx context.Context, taskID string) (map[string]any, error)

Get returns the current state of a task (tasks/get).

func (*TaskClient) Start added in v1.4.0 

func (c *TaskClient) Start(ctx context.Context, name string, args map[string]any) (res map[string]any, done bool, err error)

Start calls the tool declaring the extension. It returns the task handle, or with done set the synchronous CallToolResult if the server chose not to create a task.

func (*TaskClient) Wait added in v1.4.0 

func (c *TaskClient) Wait(ctx context.Context, taskID string) (map[string]any, error)

Wait polls the task until it is completed, failed or cancelled, answering input requests on the way, and returns its final state.

type ToolError added in v1.2.0 

type ToolError struct {
	Message string
}

ToolError represents an application-level tool error (CallToolResult with isError: true).

func (*ToolError) Error added in v1.2.0 

func (e *ToolError) Error() string

Source Files

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