Protocol

Category: Mcp_client

Source: protocol.dart

MCP wire-protocol message types (Model Context Protocol).

MCP is layered on JSON-RPC 2.0. We reuse glue_server's [JsonRpcMessage]/[JsonRpcTransport] for framing and add MCP-specific param/result shapes here.

Pure data — no I/O. See client.dart for the dispatch logic and transport/stdio.dart for the subprocess transport.

Classes

McpClientInfo

Constructor

const McpClientInfo({required this.name, required this.version})

Properties

Property	Type	Description
name	String
version	String

McpServerInfo

Constructor

const McpServerInfo({required this.name, required this.version})

factory McpServerInfo.fromJson(Map<String, dynamic> json)

Properties

Property	Type	Description
name	String
version	String

McpClientCapabilities

Constructor

const McpClientCapabilities({this.roots})

Properties

Property	Type	Description
roots	McpRootsCapability?	We advertise roots so servers (e.g. filesystem) can scope access.

McpRootsCapability

Constructor

const McpRootsCapability({this.listChanged = false})

Properties

Property	Type	Description
listChanged	bool

McpServerCapabilities

Constructor

const McpServerCapabilities({
    this.tools,
    this.prompts,
    this.resources,
    this.sampling,
    this.logging,
    this.experimental,
  })

factory McpServerCapabilities.fromJson(Map<String, dynamic> json)

Properties

Property	Type	Description
tools	McpToolsCapability?
prompts	Map<String, dynamic>?
resources	Map<String, dynamic>?
sampling	Map<String, dynamic>?
logging	Map<String, dynamic>?
experimental	Map<String, dynamic>?
supportsSampling	bool get
supportsSampling	bool get

McpToolsCapability

Constructor

const McpToolsCapability({this.listChanged = false})

factory McpToolsCapability.fromJson(Map<String, dynamic> json)

McpToolsCapability(listChanged: json['listChanged'] as bool? ?? false)

Properties

Property	Type	Description
listChanged	bool

McpInitializeResult

Constructor

const McpInitializeResult({
    required this.protocolVersion,
    required this.serverInfo,
    required this.capabilities,
    this.instructions,
  })

factory McpInitializeResult.fromJson(Map<String, dynamic> json)

Properties

Property	Type	Description
protocolVersion	String
serverInfo	McpServerInfo
capabilities	McpServerCapabilities
instructions	String?

McpToolDescriptor

Constructor

const McpToolDescriptor({
    required this.name,
    required this.description,
    required this.inputSchema,
  })

factory McpToolDescriptor.fromJson(Map<String, dynamic> json)

Properties

Property	Type	Description
name	String
description	String
inputSchema	Map<String, dynamic>

sealed McpContent

One content item in a tool call result. MCP supports text, image, and embedded resource variants; we model only text directly and pass other kinds through as opaque maps so the agent loop can ignore them.

Constructor

const McpContent()

factory McpContent.fromJson(Map<String, dynamic> json)

McpTextContent

Constructor

const McpTextContent(this.text)

Properties

Property	Type	Description
text	String

McpOpaqueContent

Constructor

const McpOpaqueContent(this.type, this.raw)

Properties

Property	Type	Description
type	String
raw	Map<String, dynamic>

McpToolCallResult

Constructor

const McpToolCallResult({required this.content, this.isError = false})

factory McpToolCallResult.fromJson(Map<String, dynamic> json)

Properties

Property	Type	Description
content	List<McpContent>
isError	bool
textPayload	String get	Concatenates all text content into a single string. Non-text items are summarised as [<type>]. Used to build the LLM-facing payload.

abstract McpErrorCode

MCP-specific JSON-RPC error codes. The standard JSON-RPC codes (-32700..-32603) come from [JsonRpcErrorCode] in glue_server.

Properties

Property	Type	Description
rateLimited	const int	Glue-reserved: the server is rate-limited. Honour Retry-After / data.retry_after_seconds and retry once.

abstract McpMethod

Properties

Property	Type	Description
initialize	const
initialized	const
toolsList	const
toolsCall	const
toolsListChanged	const
ping	const