## 通用类型 ### `Annotations`

interface Annotations \{
  audience?: Role\[];
  lastModified?: string;
  priority?: number;
}

客户端的可选注解。客户端可以使用注解来告知如何使用或显示对象

Optionalaudience

audience?: Role\[]

描述此对象或数据的预期客户。

它可以包含多个条目，以指示对多个受众有用的内容（例如，\["user", "assistant"]）。

OptionallastModified

lastModified?: string

资源最后修改的时间，作为ISO 8601格式的字符串。

应该是ISO 8601格式的字符串（例如，"2025-01-12T15:00:58Z"）。

示例：打开文件中的最后活动时间戳，附加资源时的时间戳等。

Optionalpriority

priority?: number

描述此数据对操作服务器的重要性。

值为1表示"最重要"，并表示数据实际上是必需的，而0表示"最不重要"，并表示数据完全是可选的。

TJS-type

number

### `AudioContent`

interface AudioContent \{
  \_meta?: \{ \[key: string]: unknown };
  annotations?: Annotations;
  data: string;
  mimeType: string;
  type: "audio";
}

提供给或来自LLM的音频。

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

有关\_meta使用说明，请参见通用字段：\_meta。

Optionalannotations

annotations?: Annotations

客户端的可选注解。

data

data: string

base64编码的音频数据。

mimeType

mimeType: string

音频的MIME类型。不同的提供商可能支持不同的音频类型。

### `BlobResourceContents`

interface BlobResourceContents \{
  \_meta?: \{ \[key: string]: unknown };
  blob: string;
  mimeType?: string;
  uri: string;
}

特定资源或子资源的内容。

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

有关\_meta使用说明，请参见通用字段：\_meta。

blob

blob: string

表示项目二进制数据的base64编码字符串。

OptionalmimeType

mimeType?: string

此资源的MIME类型（如果已知）。

uri

uri: string

此资源的URI。

### `BooleanSchema`

interface BooleanSchema \{
  default?: boolean;
  description?: string;
  title?: string;
  type: "boolean";
}

### `ClientCapabilities`

interface ClientCapabilities \{
  elicitation?: object;
  experimental?: \{ \[key: string]: object };
  roots?: \{ listChanged?: boolean };
  sampling?: object;
}

客户端可能支持的功能。这里定义了已知功能，但这不是封闭集合：任何客户端都可以定义自己的附加功能。

Optionalelicitation

elicitation?: object

如果客户端支持来自服务器的引出，则存在。

Optionalexperimental

experimental?: \{ \[key: string]: object }

客户端支持的实验性、非标准功能。

Optionalroots

roots?: \{ listChanged?: boolean }

如果客户端支持列出根，则存在。

Type declaration

OptionallistChanged?: boolean
客户端是否支持根列表更改的通知。

Optionalsampling

sampling?: object

如果客户端支持从LLM采样，则存在。

### `ContentBlock`

### `Cursor`

Cursor: string

用于表示分页位置的不透明令牌。

### `EmbeddedResource`

interface EmbeddedResource \{
  \_meta?: \{ \[key: string]: unknown };
  annotations?: Annotations;
  resource: TextResourceContents | BlobResourceContents;
  type: "resource";
}

嵌入到提示或工具调用结果中的资源内容。

由客户端决定如何最好地渲染嵌入资源以供LLM和/或用户使用。

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

有关\_meta使用说明，请参见通用字段：\_meta。

Optionalannotations

annotations?: Annotations

客户端的可选注解。

### `EmptyResult`

EmptyResult: Result

表示成功但不携带数据的响应。

### `EnumSchema`

interface EnumSchema \{
  default?: string;
  description?: string;
  enum: string\[];
  enumNames?: string\[];
  title?: string;
  type: "string";
}

### `Error`

interface Error \{
  code: number;
  data?: unknown;
  message: string;
}

code

code: number

The error type that occurred.

Optionaldata

data?: unknown

Additional information about the error. The value of this member is defined by the sender (e.g. detailed error information, nested errors etc.).

message

message: string

A short description of the error. The message SHOULD be limited to a concise single sentence.

### `Icon`

interface Icon \{
  mimeType?: string;
  sizes?: string\[];
  src: string;
  theme?: "light" | "dark";
}

An optionally-sized icon that can be displayed in a user interface.

OptionalmimeType

mimeType?: string

Optional MIME type override if the source MIME type is missing or generic. For example: "image/png", "image/jpeg", or "image/svg+xml".

Optionalsizes

sizes?: string\[]

Optional array of strings that specify sizes at which the icon can be used. Each string should be in WxH format (e.g., "48x48", "96x96") or "any" for scalable formats like SVG.

If not provided, the client should assume that the icon can be used at any size.

src

src: string

A standard URI pointing to an icon resource. May be an HTTP/HTTPS URL or a data: URI with Base64-encoded image data.

Consumers SHOULD takes steps to ensure URLs serving icons are from the same domain as the client/server or a trusted domain.

Consumers SHOULD take appropriate precautions when consuming SVGs as they can contain executable JavaScript.

Optionaltheme

theme?: "light" | "dark"

Optional specifier for the theme this icon is designed for. light indicates the icon is designed to be used with a light background, and dark indicates the icon is designed to be used with a dark background.

If not provided, the client should assume the icon can be used with any theme.

### `ImageContent`

interface ImageContent \{
  \_meta?: \{ \[key: string]: unknown };
  annotations?: Annotations;
  data: string;
  mimeType: string;
  type: "image";
}

An image provided to or from an LLM.

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

See General fields: \_meta for notes on \_meta usage.

Optionalannotations

annotations?: Annotations

Optional annotations for the client.

data

data: string

The base64-encoded image data.

mimeType

mimeType: string

The MIME type of the image. Different providers may support different image types.

### `Implementation`

interface Implementation \{
  icons?: Icon\[];
  name: string;
  title?: string;
  version: string;
  websiteUrl?: string;
}

Describes the MCP implementation

Optionalicons

icons?: Icon\[]

Optional set of sized icons that the client can display in a user interface.

Clients that support rendering icons MUST support at least the following MIME types:

image/png - PNG images (safe, universal compatibility)
image/jpeg (and image/jpg) - JPEG images (safe, universal compatibility)

Clients that support rendering icons SHOULD also support:

image/svg+xml - SVG images (scalable but requires security precautions)
image/webp - WebP images (modern, efficient format)

name

Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).

Optionaltitle

title?: string

Intended for UI and end-user contexts — optimized to be human-readable and easily understood, even by those unfamiliar with domain-specific terminology.

If not provided, the name should be used for display (except for Tool, where annotations.title should be given precedence over using name, if present).

OptionalwebsiteUrl

websiteUrl?: string

An optional URL of the website for this implementation.

### `JSONRPCError`

interface JSONRPCError \{
  error: Error;
  id: RequestId;
  jsonrpc: "2.0";
}

A response to a request that indicates an error occurred.

### `JSONRPCNotification`

interface JSONRPCNotification \{
  jsonrpc: "2.0";
  method: string;
  params?: \{ \_meta?: \{ \[key: string]: unknown }; \[key: string]: unknown };
}

A notification which does not expect a response.

Optionalparams

params?: \{ \_meta?: \{ \[key: string]: unknown }; \[key: string]: unknown }

Type declaration

\[key: string]: unknown
Optional\_meta?: \{ \[key: string]: unknown }
See General fields: \_meta for notes on \_meta usage.

### `JSONRPCRequest`

interface JSONRPCRequest \{
  id: RequestId;
  jsonrpc: "2.0";
  method: string;
  params?: \{
    \_meta?: \{ progressToken?: ProgressToken; \[key: string]: unknown };
    \[key: string]: unknown;
  };
}

A request that expects a response.

Optionalparams

params?: \{
\_meta?: \{ progressToken?: ProgressToken; \[key: string]: unknown };
\[key: string]: unknown;
}

Type declaration

\[key: string]: unknown
Optional\_meta?: \{ progressToken?: ProgressToken; \[key: string]: unknown }
See General fields: \_meta for notes on \_meta usage.
- OptionalprogressToken?: ProgressToken
  If specified, the caller is requesting out-of-band progress notifications for this request (as represented by notifications/progress). The value of this parameter is an opaque token that will be attached to any subsequent notifications. The receiver is not obligated to provide these notifications.

### `JSONRPCResponse`

interface JSONRPCResponse \{
  id: RequestId;
  jsonrpc: "2.0";
  result: Result;
}

A successful (non-error) response to a request.

### `LoggingLevel`

The severity of a log message.

These map to syslog message severities, as specified in RFC-5424: [https://datatracker.ietf.org/doc/html/rfc5424#section-6.2.1](https://datatracker.ietf.org/doc/html/rfc5424#section-6.2.1)

### `ModelHint`

interface ModelHint \{
name?: string;
}

Hints to use for model selection.

Keys not declared here are currently left unspecified by the spec and are up to the client to interpret.

Optionalname

name?: string

A hint for a model name.

The client SHOULD treat this as a substring of a model name; for example:

claude-3-5-sonnet should match claude-3-5-sonnet-20241022
sonnet should match claude-3-5-sonnet-20241022, claude-3-sonnet-20240229, etc.
claude should match any Claude model

The client MAY also map the string to a different provider's model name or a different model family, as long as it fills a similar niche; for example:

gemini-1.5-flash could match claude-3-haiku-20240307

### `ModelPreferences`

interface ModelPreferences \{
  costPriority?: number;
  hints?: ModelHint\[];
  intelligencePriority?: number;
  speedPriority?: number;
}

The server's preferences for model selection, requested of the client during sampling.

Because LLMs can vary along multiple dimensions, choosing the "best" model is rarely straightforward. Different models excel in different areas—some are faster but less capable, others are more capable but more expensive, and so on. This interface allows servers to express their priorities across multiple dimensions to help clients make an appropriate selection for their use case.

These preferences are always advisory. The client MAY ignore them. It is also up to the client to decide how to interpret these preferences and how to balance them against other considerations.

OptionalcostPriority

costPriority?: number

How much to prioritize cost when selecting a model. A value of 0 means cost is not important, while a value of 1 means cost is the most important factor.

TJS-type

number

Optionalhints

hints?: ModelHint\[]

Optional hints to use for model selection.

If multiple hints are specified, the client MUST evaluate them in order (such that the first match is taken).

The client SHOULD prioritize these hints over the numeric priorities, but MAY still use the priorities to select from ambiguous matches.

OptionalintelligencePriority

intelligencePriority?: number

How much to prioritize intelligence and capabilities when selecting a model. A value of 0 means intelligence is not important, while a value of 1 means intelligence is the most important factor.

TJS-type

number

OptionalspeedPriority

speedPriority?: number

How much to prioritize sampling speed (latency) when selecting a model. A value of 0 means speed is not important, while a value of 1 means speed is the most important factor.

TJS-type

number

### `NumberSchema`

interface NumberSchema \{
  default?: number;
  description?: string;
  maximum?: number;
  minimum?: number;
  title?: string;
  type: "number" | "integer";
}

### `PrimitiveSchemaDefinition`

PrimitiveSchemaDefinition:
  | StringSchema
  | NumberSchema
  | BooleanSchema
  | EnumSchema

Restricted schema definitions that only allow primitive types without nested objects or arrays.

### `ProgressToken`

ProgressToken: string | number

A progress token, used to associate progress notifications with the original request.

### `Prompt`

interface Prompt \{
  \_meta?: \{ \[key: string]: unknown };
  arguments?: PromptArgument\[];
  description?: string;
  icons?: Icon\[];
  name: string;
  title?: string;
}

A prompt or prompt template that the server offers.

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

See General fields: \_meta for notes on \_meta usage.

Optionalarguments

arguments?: PromptArgument\[]

A list of arguments to use for templating the prompt.

Optionaldescription

description?: string

An optional description of what this prompt provides

Optionalicons

icons?: Icon\[]

Optional set of sized icons that the client can display in a user interface.

Clients that support rendering icons MUST support at least the following MIME types:

image/png - PNG images (safe, universal compatibility)
image/jpeg (and image/jpg) - JPEG images (safe, universal compatibility)

Clients that support rendering icons SHOULD also support:

image/svg+xml - SVG images (scalable but requires security precautions)
image/webp - WebP images (modern, efficient format)

name

Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).

Optionaltitle

title?: string

Intended for UI and end-user contexts — optimized to be human-readable and easily understood, even by those unfamiliar with domain-specific terminology.

If not provided, the name should be used for display (except for Tool, where annotations.title should be given precedence over using name, if present).

### `PromptArgument`

interface PromptArgument \{
  description?: string;
  name: string;
  required?: boolean;
  title?: string;
}

Describes an argument that a prompt can accept.

Optionaldescription

description?: string

A human-readable description of the argument.

name

Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).

Optionalrequired

required?: boolean

Whether this argument must be provided.

Optionaltitle

title?: string

Intended for UI and end-user contexts — optimized to be human-readable and easily understood, even by those unfamiliar with domain-specific terminology.

If not provided, the name should be used for display (except for Tool, where annotations.title should be given precedence over using name, if present).

### `PromptMessage`

interface PromptMessage \{
content: ContentBlock;
role: Role;
}

Describes a message returned as part of a prompt.

This is similar to SamplingMessage, but also supports the embedding of resources from the MCP server.

### `PromptReference`

interface PromptReference \{
  name: string;
  title?: string;
  type: "ref/prompt";
}

Identifies a prompt.

name

Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).

Optionaltitle

title?: string

Intended for UI and end-user contexts — optimized to be human-readable and easily understood, even by those unfamiliar with domain-specific terminology.

If not provided, the name should be used for display (except for Tool, where annotations.title should be given precedence over using name, if present).

### `RequestId`

RequestId: string | number

A uniquely identifying ID for a request in JSON-RPC.

### `Resource`

interface Resource \{
  \_meta?: \{ \[key: string]: unknown };
  annotations?: Annotations;
  description?: string;
  icons?: Icon\[];
  mimeType?: string;
  name: string;
  size?: number;
  title?: string;
  uri: string;
}

A known resource that the server is capable of reading.

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

See General fields: \_meta for notes on \_meta usage.

Optionalannotations

annotations?: Annotations

Optional annotations for the client.

Optionaldescription

description?: string

A description of what this resource represents.

This can be used by clients to improve the LLM's understanding of available resources. It can be thought of like a "hint" to the model.

Optionalicons

icons?: Icon\[]

Optional set of sized icons that the client can display in a user interface.

Clients that support rendering icons MUST support at least the following MIME types:

image/png - PNG images (safe, universal compatibility)
image/jpeg (and image/jpg) - JPEG images (safe, universal compatibility)

Clients that support rendering icons SHOULD also support:

image/svg+xml - SVG images (scalable but requires security precautions)
image/webp - WebP images (modern, efficient format)

OptionalmimeType

mimeType?: string

The MIME type of this resource, if known.

name

Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).

Optionalsize

size?: number

The size of the raw resource content, in bytes (i.e., before base64 encoding or any tokenization), if known.

This can be used by Hosts to display file sizes and estimate context window usage.

Optionaltitle

title?: string

Intended for UI and end-user contexts — optimized to be human-readable and easily understood, even by those unfamiliar with domain-specific terminology.

If not provided, the name should be used for display (except for Tool, where annotations.title should be given precedence over using name, if present).

uri

uri: string

The URI of this resource.

### `ResourceContents`

interface ResourceContents \{
  \_meta?: \{ \[key: string]: unknown };
  mimeType?: string;
  uri: string;
}

The contents of a specific resource or sub-resource.

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

See General fields: \_meta for notes on \_meta usage.

OptionalmimeType

mimeType?: string

The MIME type of this resource, if known.

uri

uri: string

The URI of this resource.

### `ResourceLink`

interface ResourceLink \{
  \_meta?: \{ \[key: string]: unknown };
  annotations?: Annotations;
  description?: string;
  icons?: Icon\[];
  mimeType?: string;
  name: string;
  size?: number;
  title?: string;
  type: "resource\_link";
  uri: string;
}

A resource that the server is capable of reading, included in a prompt or tool call result.

Note: resource links returned by tools are not guaranteed to appear in the results of resources/list requests.

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

See General fields: \_meta for notes on \_meta usage.

Optionalannotations

annotations?: Annotations

Optional annotations for the client.

Optionaldescription

description?: string

A description of what this resource represents.

This can be used by clients to improve the LLM's understanding of available resources. It can be thought of like a "hint" to the model.

Optionalicons

icons?: Icon\[]

Optional set of sized icons that the client can display in a user interface.

Clients that support rendering icons MUST support at least the following MIME types:

image/png - PNG images (safe, universal compatibility)
image/jpeg (and image/jpg) - JPEG images (safe, universal compatibility)

Clients that support rendering icons SHOULD also support:

image/svg+xml - SVG images (scalable but requires security precautions)
image/webp - WebP images (modern, efficient format)

OptionalmimeType

mimeType?: string

The MIME type of this resource, if known.

name

Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).

Optionalsize

size?: number

The size of the raw resource content, in bytes (i.e., before base64 encoding or any tokenization), if known.

This can be used by Hosts to display file sizes and estimate context window usage.

Optionaltitle

title?: string

Intended for UI and end-user contexts — optimized to be human-readable and easily understood, even by those unfamiliar with domain-specific terminology.

If not provided, the name should be used for display (except for Tool, where annotations.title should be given precedence over using name, if present).

uri

uri: string

The URI of this resource.

### `ResourceTemplate`

interface ResourceTemplate \{
  \_meta?: \{ \[key: string]: unknown };
  annotations?: Annotations;
  description?: string;
  icons?: Icon\[];
  mimeType?: string;
  name: string;
  title?: string;
  uriTemplate: string;
}

A template description for resources available on the server.

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

See General fields: \_meta for notes on \_meta usage.

Optionalannotations

annotations?: Annotations

Optional annotations for the client.

Optionaldescription

description?: string

A description of what this template is for.

This can be used by clients to improve the LLM's understanding of available resources. It can be thought of like a "hint" to the model.

Optionalicons

icons?: Icon\[]

Optional set of sized icons that the client can display in a user interface.

Clients that support rendering icons MUST support at least the following MIME types:

image/png - PNG images (safe, universal compatibility)
image/jpeg (and image/jpg) - JPEG images (safe, universal compatibility)

Clients that support rendering icons SHOULD also support:

image/svg+xml - SVG images (scalable but requires security precautions)
image/webp - WebP images (modern, efficient format)

OptionalmimeType

mimeType?: string

The MIME type for all resources that match this template. This should only be included if all resources matching this template have the same type.

name

Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).

Optionaltitle

title?: string

Intended for UI and end-user contexts — optimized to be human-readable and easily understood, even by those unfamiliar with domain-specific terminology.

If not provided, the name should be used for display (except for Tool, where annotations.title should be given precedence over using name, if present).

uriTemplate

uriTemplate: string

A URI template (according to RFC 6570) that can be used to construct resource URIs.

### `ResourceTemplateReference`

interface ResourceTemplateReference \{
type: "ref/resource";
uri: string;
}

A reference to a resource or resource template definition.

uri

uri: string

The URI or URI template of the resource.

### `Result`

interface Result \{
\_meta?: \{ \[key: string]: unknown };
\[key: string]: unknown;
}

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

See General fields: \_meta for notes on \_meta usage.

### `Role`

Role: "user" | "assistant"

The sender or recipient of messages and data in a conversation.

### `Root`

interface Root \{
  \_meta?: \{ \[key: string]: unknown };
  name?: string;
  uri: string;
}

Represents a root directory or file that the server can operate on.

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

See General fields: \_meta for notes on \_meta usage.

Optionalname

name?: string

An optional name for the root. This can be used to provide a human-readable identifier for the root, which may be useful for display purposes or for referencing the root in other parts of the application.

uri

uri: string

The URI identifying the root. This must start with file:// for now. This restriction may be relaxed in future versions of the protocol to allow other URI schemes.

### `SamplingMessage`

interface SamplingMessage \{
content: TextContent | ImageContent | AudioContent;
role: Role;
}

Describes a message issued to or received from an LLM API.

### `ServerCapabilities`

interface ServerCapabilities \{
  completions?: object;
  experimental?: \{ \[key: string]: object };
  logging?: object;
  prompts?: \{ listChanged?: boolean };
  resources?: \{ listChanged?: boolean; subscribe?: boolean };
  tools?: \{ listChanged?: boolean };
}

Capabilities that a server may support. Known capabilities are defined here, in this schema, but this is not a closed set: any server can define its own, additional capabilities.

Optionalcompletions

completions?: object

Present if the server supports argument autocompletion suggestions.

Optionalexperimental

experimental?: \{ \[key: string]: object }

Experimental, non-standard capabilities that the server supports.

Optionallogging

logging?: object

Present if the server supports sending log messages to the client.

Optionalprompts

prompts?: \{ listChanged?: boolean }

Present if the server offers any prompt templates.

Type declaration

OptionallistChanged?: boolean
Whether this server supports notifications for changes to the prompt list.

Optionalresources

resources?: \{ listChanged?: boolean; subscribe?: boolean }

Present if the server offers any resources to read.

Type declaration

OptionallistChanged?: boolean
Whether this server supports notifications for changes to the resource list.
Optionalsubscribe?: boolean
Whether this server supports subscribing to resource updates.

Optionaltools

tools?: \{ listChanged?: boolean }

Present if the server offers any tools to call.

Type declaration

OptionallistChanged?: boolean
Whether this server supports notifications for changes to the tool list.

### `StringSchema`

interface StringSchema \{
  default?: string;
  description?: string;
  format?: "uri" | "email" | "date" | "date-time";
  maxLength?: number;
  minLength?: number;
  title?: string;
  type: "string";
}

### `TextContent`

interface TextContent \{
  \_meta?: \{ \[key: string]: unknown };
  annotations?: Annotations;
  text: string;
  type: "text";
}

Text provided to or from an LLM.

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

See General fields: \_meta for notes on \_meta usage.

Optionalannotations

annotations?: Annotations

Optional annotations for the client.

text

text: string

The text content of the message.

### `TextResourceContents`

interface TextResourceContents \{
  \_meta?: \{ \[key: string]: unknown };
  mimeType?: string;
  text: string;
  uri: string;
}

The contents of a specific resource or sub-resource.

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

See General fields: \_meta for notes on \_meta usage.

OptionalmimeType

mimeType?: string

The MIME type of this resource, if known.

text

text: string

The text of the item. This must only be set if the item can actually be represented as text (not binary data).

uri

uri: string

The URI of this resource.

### `Tool`

interface Tool \{
  \_meta?: \{ \[key: string]: unknown };
  annotations?: ToolAnnotations;
  description?: string;
  icons?: Icon\[];
  inputSchema: \{
    properties?: \{ \[key: string]: object };
    required?: string\[];
    type: "object";
  };
  name: string;
  outputSchema?: \{
    properties?: \{ \[key: string]: object };
    required?: string\[];
    type: "object";
  };
  title?: string;
}

Definition for a tool the client can call.

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

See General fields: \_meta for notes on \_meta usage.

Optionalannotations

annotations?: ToolAnnotations

Optional additional tool information.

Display name precedence order is: title, annotations.title, then name.

Optionaldescription

description?: string

A human-readable description of the tool.

This can be used by clients to improve the LLM's understanding of available tools. It can be thought of like a "hint" to the model.

Optionalicons

icons?: Icon\[]

Optional set of sized icons that the client can display in a user interface.

Clients that support rendering icons MUST support at least the following MIME types:

image/png - PNG images (safe, universal compatibility)
image/jpeg (and image/jpg) - JPEG images (safe, universal compatibility)

Clients that support rendering icons SHOULD also support:

image/svg+xml - SVG images (scalable but requires security precautions)
image/webp - WebP images (modern, efficient format)

inputSchema

inputSchema: \{
  properties?: \{ \[key: string]: object };
  required?: string\[];
  type: "object";
}

A JSON Schema object defining the expected parameters for the tool.

name

Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).

OptionaloutputSchema

outputSchema?: \{
  properties?: \{ \[key: string]: object };
  required?: string\[];
  type: "object";
}

An optional JSON Schema object defining the structure of the tool's output returned in the structuredContent field of a CallToolResult.

Optionaltitle

title?: string

Intended for UI and end-user contexts — optimized to be human-readable and easily understood, even by those unfamiliar with domain-specific terminology.

If not provided, the name should be used for display (except for Tool, where annotations.title should be given precedence over using name, if present).

### `ToolAnnotations`

interface ToolAnnotations \{
  destructiveHint?: boolean;
  idempotentHint?: boolean;
  openWorldHint?: boolean;
  readOnlyHint?: boolean;
  title?: string;
}

Additional properties describing a Tool to clients.

NOTE: all properties in ToolAnnotations are hints. They are not guaranteed to provide a faithful description of tool behavior (including descriptive properties like title).

Clients should never make tool use decisions based on ToolAnnotations received from untrusted servers.

OptionaldestructiveHint

destructiveHint?: boolean

If true, the tool may perform destructive updates to its environment. If false, the tool performs only additive updates.

(This property is meaningful only when readOnlyHint == false)

Default: true

OptionalidempotentHint

idempotentHint?: boolean

If true, calling the tool repeatedly with the same arguments will have no additional effect on its environment.

(This property is meaningful only when readOnlyHint == false)

Default: false

OptionalopenWorldHint

openWorldHint?: boolean

If true, this tool may interact with an "open world" of external entities. If false, the tool's domain of interaction is closed. For example, the world of a web search tool is open, whereas that of a memory tool is not.

Default: true

OptionalreadOnlyHint

readOnlyHint?: boolean

If true, the tool does not modify its environment.

Default: false

Optionaltitle

title?: string

A human-readable title for the tool.

## `completion/complete` ### `CompleteRequest`

interface CompleteRequest \{
  id: RequestId;
  jsonrpc: "2.0";
  method: "completion/complete";
  params: \{
    argument: \{ name: string; value: string };
    context?: \{ arguments?: \{ \[key: string]: string } };
    ref: PromptReference | ResourceTemplateReference;
  };
}

A request from the client to the server, to ask for completion options.

params

params: \{
  argument: \{ name: string; value: string };
  context?: \{ arguments?: \{ \[key: string]: string } };
  ref: PromptReference | ResourceTemplateReference;
}

Type declaration

argument: \{ name: string; value: string }
The argument's information
- name: string
  The name of the argument
- value: string
  The value of the argument to use for completion matching.
Optionalcontext?: \{ arguments?: \{ \[key: string]: string } }
Additional, optional context for completions
- Optionalarguments?: \{ \[key: string]: string }
  Previously-resolved variables in a URI template or prompt.
ref: PromptReference | ResourceTemplateReference

### `CompleteResult`

interface CompleteResult \{
  \_meta?: \{ \[key: string]: unknown };
  completion: \{ hasMore?: boolean; total?: number; values: string\[] };
  \[key: string]: unknown;
}

The server's response to a completion/complete request

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

See General fields: \_meta for notes on \_meta usage.

completion

completion: \{ hasMore?: boolean; total?: number; values: string\[] }

Type declaration

OptionalhasMore?: boolean
Indicates whether there are additional completion options beyond those provided in the current response, even if the exact total is unknown.
Optionaltotal?: number
The total number of completion options available. This can exceed the number of values actually sent in the response.
values: string\[]
An array of completion values. Must not exceed 100 items.

## `elicitation/create` ### `ElicitRequest`

interface ElicitRequest \{
  id: RequestId;
  jsonrpc: "2.0";
  method: "elicitation/create";
  params: \{
    message: string;
    requestedSchema: \{
      properties: \{ \[key: string]: PrimitiveSchemaDefinition };
      required?: string\[];
      type: "object";
    };
  };
}

A request from the server to elicit additional information from the user via the client.

params

params: \{
  message: string;
  requestedSchema: \{
    properties: \{ \[key: string]: PrimitiveSchemaDefinition };
    required?: string\[];
    type: "object";
  };
}

Type declaration

message: string
The message to present to the user.
requestedSchema: \{
  properties: \{ \[key: string]: PrimitiveSchemaDefinition };
  required?: string\[];
  type: "object";
}
A restricted subset of JSON Schema. Only top-level properties are allowed, without nesting.

### `ElicitResult`

interface ElicitResult \{
  \_meta?: \{ \[key: string]: unknown };
  action: "accept" | "decline" | "cancel";
  content?: \{ \[key: string]: string | number | boolean };
  \[key: string]: unknown;
}

The client's response to an elicitation request.

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

See General fields: \_meta for notes on \_meta usage.

action

action: "accept" | "decline" | "cancel"

The user action in response to the elicitation.

"accept": User submitted the form/confirmed the action
"decline": User explicitly decline the action
"cancel": User dismissed without making an explicit choice

Optionalcontent

content?: \{ \[key: string]: string | number | boolean }

The submitted form data, only present when action is "accept". Contains values matching the requested schema.

## `initialize` ### `InitializeRequest`

interface InitializeRequest \{
  id: RequestId;
  jsonrpc: "2.0";
  method: "initialize";
  params: \{
    capabilities: ClientCapabilities;
    clientInfo: Implementation;
    protocolVersion: string;
  };
}

This request is sent from the client to the server when it first connects, asking it to begin initialization.

params

params: \{
  capabilities: ClientCapabilities;
  clientInfo: Implementation;
  protocolVersion: string;
}

Type declaration

capabilities: ClientCapabilities
clientInfo: Implementation
protocolVersion: string
The latest version of the Model Context Protocol that the client supports. The client MAY decide to support older versions as well.

### `InitializeResult`

interface InitializeResult \{
  \_meta?: \{ \[key: string]: unknown };
  capabilities: ServerCapabilities;
  instructions?: string;
  protocolVersion: string;
  serverInfo: Implementation;
  \[key: string]: unknown;
}

After receiving an initialize request from the client, the server sends this response.

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

See General fields: \_meta for notes on \_meta usage.

Optionalinstructions

instructions?: string

Instructions describing how to use the server and its features.

This can be used by clients to improve the LLM's understanding of available tools, resources, etc. It can be thought of like a "hint" to the model. For example, this information MAY be added to the system prompt.

protocolVersion

protocolVersion: string

The version of the Model Context Protocol that the server wants to use. This may not match the version that the client requested. If the client cannot support this version, it MUST disconnect.

## `logging/setLevel` ### `SetLevelRequest`

interface SetLevelRequest \{
  id: RequestId;
  jsonrpc: "2.0";
  method: "logging/setLevel";
  params: \{ level: LoggingLevel };
}

A request from the client to the server, to enable or adjust logging.

params

params: \{ level: LoggingLevel }

Type declaration

level: LoggingLevel
The level of logging that the client wants to receive from the server. The server should send all logs at this level and higher (i.e., more severe) to the client as notifications/message.

## `notifications/cancelled` ### `CancelledNotification`

interface CancelledNotification \{
  jsonrpc: "2.0";
  method: "notifications/cancelled";
  params: \{ reason?: string; requestId: RequestId };
}

This notification can be sent by either side to indicate that it is cancelling a previously-issued request.

The request SHOULD still be in-flight, but due to communication latency, it is always possible that this notification MAY arrive after the request has already finished.

This notification indicates that the result will be unused, so any associated processing SHOULD cease.

A client MUST NOT attempt to cancel its initialize request.

params

params: \{ reason?: string; requestId: RequestId }

Type declaration

Optionalreason?: string
An optional string describing the reason for the cancellation. This MAY be logged or presented to the user.
requestId: RequestId
The ID of the request to cancel.

This MUST correspond to the ID of a request previously issued in the same direction.

## `notifications/initialized` ### `InitializedNotification`

interface InitializedNotification \{
  jsonrpc: "2.0";
  method: "notifications/initialized";
  params?: \{ \_meta?: \{ \[key: string]: unknown }; \[key: string]: unknown };
}

This notification is sent from the client to the server after initialization has finished.

Optionalparams

params?: \{ \_meta?: \{ \[key: string]: unknown }; \[key: string]: unknown }

Type declaration

\[key: string]: unknown
Optional\_meta?: \{ \[key: string]: unknown }
See General fields: \_meta for notes on \_meta usage.

## `notifications/message` ### `LoggingMessageNotification`

interface LoggingMessageNotification \{
  jsonrpc: "2.0";
  method: "notifications/message";
  params: \{ data: unknown; level: LoggingLevel; logger?: string };
}

JSONRPCNotification of a log message passed from server to client. If no logging/setLevel request has been sent from the client, the server MAY decide which messages to send automatically.

params

params: \{ data: unknown; level: LoggingLevel; logger?: string }

Type declaration

data: unknown
The data to be logged, such as a string message or an object. Any JSON serializable type is allowed here.
level: LoggingLevel
The severity of this log message.
Optionallogger?: string
An optional name of the logger issuing this message.

## `notifications/progress` ### `ProgressNotification`

interface ProgressNotification \{
  jsonrpc: "2.0";
  method: "notifications/progress";
  params: \{
    message?: string;
    progress: number;
    progressToken: ProgressToken;
    total?: number;
  };
}

An out-of-band notification used to inform the receiver of a progress update for a long-running request.

params

params: \{
  message?: string;
  progress: number;
  progressToken: ProgressToken;
  total?: number;
}

Type declaration

Optionalmessage?: string
An optional message describing the current progress.
progress: number
The progress thus far. This should increase every time progress is made, even if the total is unknown.

TJS-type
number
progressToken: ProgressToken
The progress token which was given in the initial request, used to associate this notification with the request that is proceeding.
Optionaltotal?: number
Total number of items to process (or total progress required), if known.

TJS-type
number

## `notifications/prompts/list_changed` ### `PromptListChangedNotification`

interface PromptListChangedNotification \{
  jsonrpc: "2.0";
  method: "notifications/prompts/list\_changed";
  params?: \{ \_meta?: \{ \[key: string]: unknown }; \[key: string]: unknown };
}

An optional notification from the server to the client, informing it that the list of prompts it offers has changed. This may be issued by servers without any previous subscription from the client.

Optionalparams

params?: \{ \_meta?: \{ \[key: string]: unknown }; \[key: string]: unknown }

Type declaration

\[key: string]: unknown
Optional\_meta?: \{ \[key: string]: unknown }
See General fields: \_meta for notes on \_meta usage.

## `notifications/resources/list_changed` ### `ResourceListChangedNotification`

interface ResourceListChangedNotification \{
  jsonrpc: "2.0";
  method: "notifications/resources/list\_changed";
  params?: \{ \_meta?: \{ \[key: string]: unknown }; \[key: string]: unknown };
}

An optional notification from the server to the client, informing it that the list of resources it can read from has changed. This may be issued by servers without any previous subscription from the client.

Optionalparams

params?: \{ \_meta?: \{ \[key: string]: unknown }; \[key: string]: unknown }

Type declaration

\[key: string]: unknown
Optional\_meta?: \{ \[key: string]: unknown }
See General fields: \_meta for notes on \_meta usage.

## `notifications/resources/updated` ### `ResourceUpdatedNotification`

interface ResourceUpdatedNotification \{
  jsonrpc: "2.0";
  method: "notifications/resources/updated";
  params: \{ uri: string };
}

A notification from the server to the client, informing it that a resource has changed and may need to be read again. This should only be sent if the client previously sent a resources/subscribe request.

params

params: \{ uri: string }

Type declaration

uri: string
The URI of the resource that has been updated. This might be a sub-resource of the one that the client actually subscribed to.

## `notifications/roots/list_changed` ### `RootsListChangedNotification`

interface RootsListChangedNotification \{
  jsonrpc: "2.0";
  method: "notifications/roots/list\_changed";
  params?: \{ \_meta?: \{ \[key: string]: unknown }; \[key: string]: unknown };
}

A notification from the client to the server, informing it that the list of roots has changed. This notification should be sent whenever the client adds, removes, or modifies any root. The server should then request an updated list of roots using the ListRootsRequest.

Optionalparams

params?: \{ \_meta?: \{ \[key: string]: unknown }; \[key: string]: unknown }

Type declaration

\[key: string]: unknown
Optional\_meta?: \{ \[key: string]: unknown }
See General fields: \_meta for notes on \_meta usage.

## `notifications/tools/list_changed` ### `ToolListChangedNotification`

interface ToolListChangedNotification \{
  jsonrpc: "2.0";
  method: "notifications/tools/list\_changed";
  params?: \{ \_meta?: \{ \[key: string]: unknown }; \[key: string]: unknown };
}

An optional notification from the server to the client, informing it that the list of tools it offers has changed. This may be issued by servers without any previous subscription from the client.

Optionalparams

params?: \{ \_meta?: \{ \[key: string]: unknown }; \[key: string]: unknown }

Type declaration

\[key: string]: unknown
Optional\_meta?: \{ \[key: string]: unknown }
See General fields: \_meta for notes on \_meta usage.

## `ping` ### `PingRequest`

interface PingRequest \{
  id: RequestId;
  jsonrpc: "2.0";
  method: "ping";
  params?: \{
    \_meta?: \{ progressToken?: ProgressToken; \[key: string]: unknown };
    \[key: string]: unknown;
  };
}

A ping, issued by either the server or the client, to check that the other party is still alive. The receiver must promptly respond, or else may be disconnected.

Optionalparams

params?: \{
\_meta?: \{ progressToken?: ProgressToken; \[key: string]: unknown };
\[key: string]: unknown;
}

Type declaration

\[key: string]: unknown
Optional\_meta?: \{ progressToken?: ProgressToken; \[key: string]: unknown }
See General fields: \_meta for notes on \_meta usage.
- OptionalprogressToken?: ProgressToken
  If specified, the caller is requesting out-of-band progress notifications for this request (as represented by notifications/progress). The value of this parameter is an opaque token that will be attached to any subsequent notifications. The receiver is not obligated to provide these notifications.

## `prompts/get` ### `GetPromptRequest`

interface GetPromptRequest \{
  id: RequestId;
  jsonrpc: "2.0";
  method: "prompts/get";
  params: \{ arguments?: \{ \[key: string]: string }; name: string };
}

Used by the client to get a prompt provided by the server.

params

params: \{ arguments?: \{ \[key: string]: string }; name: string }

Type declaration

Optionalarguments?: \{ \[key: string]: string }
Arguments to use for templating the prompt.
name: string
The name of the prompt or prompt template.

### `GetPromptResult`

interface GetPromptResult \{
  \_meta?: \{ \[key: string]: unknown };
  description?: string;
  messages: PromptMessage\[];
  \[key: string]: unknown;
}

The server's response to a prompts/get request from the client.

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

See General fields: \_meta for notes on \_meta usage.

Optionaldescription

description?: string

An optional description for the prompt.

## `prompts/list` ### `ListPromptsRequest`

interface ListPromptsRequest \{
  id: RequestId;
  jsonrpc: "2.0";
  method: "prompts/list";
  params?: \{ cursor?: string };
}

Sent from the client to request a list of prompts and prompt templates the server has.

Optionalparams

params?: \{ cursor?: string }

Type declaration

Optionalcursor?: string
An opaque token representing the current pagination position. If provided, the server should return results starting after this cursor.

### `ListPromptsResult`

interface ListPromptsResult \{
  \_meta?: \{ \[key: string]: unknown };
  nextCursor?: string;
  prompts: Prompt\[];
  \[key: string]: unknown;
}

The server's response to a prompts/list request from the client.

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

See General fields: \_meta for notes on \_meta usage.

OptionalnextCursor

nextCursor?: string

An opaque token representing the pagination position after the last returned result. If present, there may be more results available.

## `resources/list` ### `ListResourcesRequest`

interface ListResourcesRequest \{
  id: RequestId;
  jsonrpc: "2.0";
  method: "resources/list";
  params?: \{ cursor?: string };
}

Sent from the client to request a list of resources the server has.

Optionalparams

params?: \{ cursor?: string }

Type declaration

Optionalcursor?: string
An opaque token representing the current pagination position. If provided, the server should return results starting after this cursor.

### `ListResourcesResult`

interface ListResourcesResult \{
  \_meta?: \{ \[key: string]: unknown };
  nextCursor?: string;
  resources: Resource\[];
  \[key: string]: unknown;
}

The server's response to a resources/list request from the client.

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

See General fields: \_meta for notes on \_meta usage.

OptionalnextCursor

nextCursor?: string

An opaque token representing the pagination position after the last returned result. If present, there may be more results available.

## `resources/read` ### `ReadResourceRequest`

interface ReadResourceRequest \{
  id: RequestId;
  jsonrpc: "2.0";
  method: "resources/read";
  params: \{ uri: string };
}

Sent from the client to the server, to read a specific resource URI.

params

params: \{ uri: string }

Type declaration

uri: string
The URI of the resource to read. The URI can use any protocol; it is up to the server how to interpret it.

### `ReadResourceResult`

interface ReadResourceResult \{
  \_meta?: \{ \[key: string]: unknown };
  contents: (TextResourceContents | BlobResourceContents)\[];
  \[key: string]: unknown;
}

The server's response to a resources/read request from the client.

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

See General fields: \_meta for notes on \_meta usage.

## `resources/subscribe` ### `SubscribeRequest`

interface SubscribeRequest \{
  id: RequestId;
  jsonrpc: "2.0";
  method: "resources/subscribe";
  params: \{ uri: string };
}

Sent from the client to request resources/updated notifications from the server whenever a particular resource changes.

params

params: \{ uri: string }

Type declaration

uri: string
The URI of the resource to subscribe to. The URI can use any protocol; it is up to the server how to interpret it.

## `resources/templates/list` ### `ListResourceTemplatesRequest`

interface ListResourceTemplatesRequest \{
  id: RequestId;
  jsonrpc: "2.0";
  method: "resources/templates/list";
  params?: \{ cursor?: string };
}

Sent from the client to request a list of resource templates the server has.

Optionalparams

params?: \{ cursor?: string }

Type declaration

Optionalcursor?: string
An opaque token representing the current pagination position. If provided, the server should return results starting after this cursor.

### `ListResourceTemplatesResult`

interface ListResourceTemplatesResult \{
  \_meta?: \{ \[key: string]: unknown };
  nextCursor?: string;
  resourceTemplates: ResourceTemplate\[];
  \[key: string]: unknown;
}

The server's response to a resources/templates/list request from the client.

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

See General fields: \_meta for notes on \_meta usage.

OptionalnextCursor

nextCursor?: string

An opaque token representing the pagination position after the last returned result. If present, there may be more results available.

## `resources/unsubscribe` ### `UnsubscribeRequest`

interface UnsubscribeRequest \{
  id: RequestId;
  jsonrpc: "2.0";
  method: "resources/unsubscribe";
  params: \{ uri: string };
}

Sent from the client to request cancellation of resources/updated notifications from the server. This should follow a previous resources/subscribe request.

params

params: \{ uri: string }

Type declaration

uri: string
The URI of the resource to unsubscribe from.

## `roots/list` ### `ListRootsRequest`

interface ListRootsRequest \{
  id: RequestId;
  jsonrpc: "2.0";
  method: "roots/list";
  params?: \{
    \_meta?: \{ progressToken?: ProgressToken; \[key: string]: unknown };
    \[key: string]: unknown;
  };
}

Sent from the server to request a list of root URIs from the client. Roots allow servers to ask for specific directories or files to operate on. A common example for roots is providing a set of repositories or directories a server should operate on.

This request is typically used when the server needs to understand the file system structure or access specific locations that the client has permission to read from.

Optionalparams

params?: \{
\_meta?: \{ progressToken?: ProgressToken; \[key: string]: unknown };
\[key: string]: unknown;
}

Type declaration

\[key: string]: unknown
Optional\_meta?: \{ progressToken?: ProgressToken; \[key: string]: unknown }
See General fields: \_meta for notes on \_meta usage.
- OptionalprogressToken?: ProgressToken
  If specified, the caller is requesting out-of-band progress notifications for this request (as represented by notifications/progress). The value of this parameter is an opaque token that will be attached to any subsequent notifications. The receiver is not obligated to provide these notifications.

### `ListRootsResult`

interface ListRootsResult \{
  \_meta?: \{ \[key: string]: unknown };
  roots: Root\[];
  \[key: string]: unknown;
}

The client's response to a roots/list request from the server. This result contains an array of Root objects, each representing a root directory or file that the server can operate on.

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

See General fields: \_meta for notes on \_meta usage.

## `sampling/createMessage` ### `CreateMessageRequest`

interface CreateMessageRequest \{
  id: RequestId;
  jsonrpc: "2.0";
  method: "sampling/createMessage";
  params: \{
    includeContext?: "none" | "thisServer" | "allServers";
    maxTokens: number;
    messages: SamplingMessage\[];
    metadata?: object;
    modelPreferences?: ModelPreferences;
    stopSequences?: string\[];
    systemPrompt?: string;
    temperature?: number;
  };
}

A request from the server to sample an LLM via the client. The client has full discretion over which model to select. The client should also inform the user before beginning sampling, to allow them to inspect the request (human in the loop) and decide whether to approve it.

params

params: \{
  includeContext?: "none" | "thisServer" | "allServers";
  maxTokens: number;
  messages: SamplingMessage\[];
  metadata?: object;
  modelPreferences?: ModelPreferences;
  stopSequences?: string\[];
  systemPrompt?: string;
  temperature?: number;
}

Type declaration

OptionalincludeContext?: "none" | "thisServer" | "allServers"
A request to include context from one or more MCP servers (including the caller), to be attached to the prompt. The client MAY ignore this request.
maxTokens: number
The requested maximum number of tokens to sample (to prevent runaway completions).

The client MAY choose to sample fewer tokens than the requested maximum.
messages: SamplingMessage\[]
Optionalmetadata?: object
Optional metadata to pass through to the LLM provider. The format of this metadata is provider-specific.
OptionalmodelPreferences?: ModelPreferences
The server's preferences for which model to select. The client MAY ignore these preferences.
OptionalstopSequences?: string\[]
OptionalsystemPrompt?: string
An optional system prompt the server wants to use for sampling. The client MAY modify or omit this prompt.
Optionaltemperature?: number
TJS-type
number

### `CreateMessageResult`

interface CreateMessageResult \{
  \_meta?: \{ \[key: string]: unknown };
  content: TextContent | ImageContent | AudioContent;
  model: string;
  role: Role;
  stopReason?: string;
  \[key: string]: unknown;
}

The client's response to a sampling/create\_message request from the server. The client should inform the user before returning the sampled message, to allow them to inspect the response (human in the loop) and decide whether to allow the server to see it.

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

See General fields: \_meta for notes on \_meta usage.

model

model: string

The name of the model that generated the message.

OptionalstopReason

stopReason?: string

The reason why sampling stopped, if known.

## `tools/call` ### `CallToolRequest`

interface CallToolRequest \{
  id: RequestId;
  jsonrpc: "2.0";
  method: "tools/call";
  params: \{ arguments?: \{ \[key: string]: unknown }; name: string };
}

Used by the client to invoke a tool provided by the server.

### `CallToolResult`

interface CallToolResult \{
  \_meta?: \{ \[key: string]: unknown };
  content: ContentBlock\[];
  isError?: boolean;
  structuredContent?: \{ \[key: string]: unknown };
  \[key: string]: unknown;
}

The server's response to a tool call.

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

See General fields: \_meta for notes on \_meta usage.

content

content: ContentBlock\[]

A list of content objects that represent the unstructured result of the tool call.

OptionalisError

isError?: boolean

Whether the tool call ended in an error.

If not set, this is assumed to be false (the call was successful).

Any errors that originate from the tool SHOULD be reported inside the result object, with isError set to true, not as an MCP protocol-level error response. Otherwise, the LLM would not be able to see that an error occurred and self-correct.

However, any errors in finding the tool, an error indicating that the server does not support tool calls, or any other exceptional conditions, should be reported as an MCP error response.

OptionalstructuredContent

structuredContent?: \{ \[key: string]: unknown }

An optional JSON object that represents the structured result of the tool call.

## `tools/list` ### `ListToolsRequest`

interface ListToolsRequest \{
  id: RequestId;
  jsonrpc: "2.0";
  method: "tools/list";
  params?: \{ cursor?: string };
}

Sent from the client to request a list of tools the server has.

Optionalparams

params?: \{ cursor?: string }

Type declaration

Optionalcursor?: string
An opaque token representing the current pagination position. If provided, the server should return results starting after this cursor.

### `ListToolsResult`

interface ListToolsResult \{
  \_meta?: \{ \[key: string]: unknown };
  nextCursor?: string;
  tools: Tool\[];
  \[key: string]: unknown;
}

The server's response to a tools/list request from the client.

Optional\_meta

\_meta?: \{ \[key: string]: unknown }

See General fields: \_meta for notes on \_meta usage.

OptionalnextCursor

nextCursor?: string

An opaque token representing the pagination position after the last returned result. If present, there may be more results available.