pharo-mcp

API Reference

Complete class and method reference for LLM-Pharo-MCP.

McpServer

The main MCP server class. Manages tools, resources, prompts, and handles protocol messages.

Class Methods

Method Description
McpServer class >> name: version: Create a server with a given name and version
McpServer class >> default Create a server with default name and version from McpConstants

Instance Methods – Configuration

Method Description
name / name: Get/set the server name
version / version: Get/set the server version
capabilities / capabilities: Get/set the McpServerCapabilities
transport / transport: Get/set the transport

Instance Methods – Tools

Method Description
addTool: Register an McpTool
removeTool: Remove a tool by name
toolNamed: Look up a tool by name (returns nil if not found)
tools Get the tools dictionary

Instance Methods – Resources

Method Description
addResource: Register an McpResource
removeResource: Remove a resource by URI
resourceAtUri: Look up a resource by URI (returns nil if not found)
resources Get the resources dictionary
addResourceTemplate: Register an McpResourceTemplate
resourceTemplates Get the resource templates dictionary

Instance Methods – Prompts

Method Description
addPrompt: Register an McpPrompt
removePrompt: Remove a prompt by name
promptNamed: Look up a prompt by name (returns nil if not found)
prompts Get the prompts dictionary

Instance Methods – Lifecycle

Method Description
start Start the server (transport must be set)
stop Stop the server
isInitialized Whether the client has sent notifications/initialized

McpTool

Represents an executable tool.

Class Methods

Method Description
name: description: inputSchema: handler: Create a tool with full schema
name: description: handler: Create a tool with empty schema (no params)

Instance Methods

Method Description
name / name: Get/set the tool name
description / description: Get/set the tool description
inputSchema / inputSchema: Get/set the input McpSchema
handler / handler: Get/set the handler block [ :args | ... ]
executeWith: Execute the tool with an arguments dictionary. Returns McpToolResult
asDictionary Convert to MCP protocol dictionary

McpSchema

JSON Schema representation for tool input validation.

Class Methods – Primitives

Method Description
string String type schema
string: String type with description
number Number type schema
number: Number type with description
integer Integer type schema
integer: Integer type with description
boolean Boolean type schema
boolean: Boolean type with description

Class Methods – Complex Types

Method Description
object: Object schema from property associations { 'name' -> McpSchema string }
object: required: Object schema with required field names
array: Array schema with item schema
enum: String enum schema with allowed values

Instance Methods

Method Description
type / type: Get/set the JSON Schema type
properties / properties: Get/set properties (for object type)
required / required: Get/set required field names (for object type)
description / description: Get/set description
items / items: Get/set items schema (for array type)
enum / enum: Get/set enum values
asDictionary Convert to JSON Schema dictionary

McpResource

Represents a static resource with a fixed URI.

Class Methods

Method Description
uri: name: description: mimeType: handler: Full constructor
uri: name: description: handler: Constructor with default text/plain MIME type

Instance Methods

Method Description
uri / uri: Get/set the resource URI
name / name: Get/set the resource name
description / description: Get/set the description
mimeType / mimeType: Get/set the MIME type
handler / handler: Get/set the handler block [ ^ { McpContentItem ... } ]
read Execute the handler. Returns array of McpContentItem
asDictionary Convert to MCP protocol dictionary

McpResourceTemplate

Represents a dynamic resource with a URI template containing {param} placeholders.

Class Methods

Method Description
uriTemplate: name: description: mimeType: handler: Full constructor
uriTemplate: name: description: handler: Constructor with default text/plain MIME type

Instance Methods

Method Description
uriTemplate / uriTemplate: Get/set the URI template
name / name: Get/set the name
description / description: Get/set the description
mimeType / mimeType: Get/set the MIME type
handler / handler: Get/set the handler block [ :params | ... ]
extractParams: Extract parameters from a URI. Returns a Dictionary or nil
matchesUri: Check if a URI matches this template
readWithUri: Read by extracting params from URI and calling handler
asDictionary Convert to MCP protocol dictionary

McpPrompt

Represents a prompt template.

Class Methods

Method Description
name: description: arguments: handler: Full constructor with arguments
name: description: handler: Constructor with no arguments

Instance Methods

Method Description
name / name: Get/set the prompt name
description / description: Get/set the description
arguments / arguments: Get/set the array of McpPromptArgument
handler / handler: Get/set the handler block [ :args | ... ]
getWithArguments: Execute with arguments dictionary. Returns result dictionary
asDictionary Convert to MCP protocol dictionary

McpPromptArgument

Defines an argument for a prompt.

Class Methods

Method Description
name: description: Create an optional argument
name: description: required: Create with explicit required flag
required: description: Create a required argument (first param is the name)

Instance Methods

Method Description
name / name: Get/set the argument name
description / description: Get/set the description
required / required: Get/set the required flag
isRequired Check if this argument is required
asDictionary Convert to dictionary

McpPromptMessage

A message within a prompt (user or assistant role).

Class Methods

Method Description
user: Create a user message with text content
assistant: Create an assistant message with text content
role: content: Create with custom role and McpContentItem

Instance Methods

Method Description
role / role: Get/set the role ('user' or 'assistant')
content / content: Get/set the McpContentItem
asDictionary Convert to dictionary

McpContentItem

Represents content in tool results, resource reads, and prompt messages.

Class Methods

Method Description
text: Create text content
image: mimeType: Create image content (base64 data)
resource: text: mimeType: Create embedded resource content

Instance Methods

Method Description
type / type: Get/set the content type ('text', 'image', 'resource')
text / text: Get/set text content
data / data: Get/set base64 image data
mimeType / mimeType: Get/set MIME type
uri / uri: Get/set resource URI
isText / isImage / isResource Type checks
asDictionary Convert to MCP content dictionary

McpToolResult

Result returned from tool execution.

Class Methods

Method Description
successText: Create success result with text content
errorText: Create error result with text content
success: Create success result with content items array
error: Create error result with content items array

Instance Methods

Method Description
content / content: Get/set the content items array
isError / isError: Get/set the error flag
asDictionary Convert to MCP result dictionary

McpServerCapabilities

Server capability flags advertised during initialization.

Instance Methods

Method Description
supportsTools / supportsTools: Get/set tools capability (default: true)
supportsResources / supportsResources: Get/set resources capability (default: true)
supportsPrompts / supportsPrompts: Get/set prompts capability (default: true)
supportsResourceSubscriptions / supportsResourceSubscriptions: Get/set subscription support (default: false)
asDictionary Convert to MCP capabilities dictionary

McpConstants

Shared pool with protocol constants.

Class Methods

Method Value Description
mcpProtocolVersion '2025-03-26' MCP protocol version
mcpServerName 'pharo-mcp' Default server name
mcpServerVersion '0.1.0' Default server version
errorCodeParseError -32700 JSON parse error
errorCodeInvalidRequest -32600 Invalid JSON-RPC request
errorCodeMethodNotFound -32601 Method not found
errorCodeInvalidParams -32602 Invalid parameters
errorCodeInternalError -32603 Internal server error

Transport Classes

McpTransport (Abstract)

Method Description
messageHandler: Set the incoming message callback
start Start the transport
stop Stop the transport
sendMessage: Send a JSON string

McpStdioTransport

Extends McpTransport for stdin/stdout communication.

Method Description
McpStdioTransport class >> stdin: stdout: Create with input/output streams
isRunning Check if the read loop is active

McpInMemoryTransport

Extends McpTransport for testing.

Method Description
sentMessages Get all sent messages
lastSentMessage Get last sent JSON string
lastSentParsed Get last sent message parsed as dictionary
simulateReceive: Simulate receiving a message
reset Clear sent messages

JSON-RPC Classes

McpJsonRpcMessage (Abstract)

Method Description
McpJsonRpcMessage class >> fromDictionary: Parse a dictionary into the correct subclass
McpJsonRpcMessage class >> fromJsonString: Parse a JSON string into the correct subclass
jsonrpc Returns '2.0'
asDictionary Convert to dictionary (abstract)
asJsonString Convert to JSON string

McpJsonRpcRequest

Method Description
id / method / params Request fields
isRequest Returns true

McpJsonRpcResponse

Method Description
id / result / error Response fields
isSuccess / isError Check response type

McpJsonRpcNotification

Method Description
method / params Notification fields
isNotification Returns true

McpJsonRpcError

Method Description
code / message / data Error fields
Factory methods parseError, invalidRequest, methodNotFound, methodNotFound:, invalidParams, invalidParams:, internalError, internalError:
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