mcpkit-core 0.7.0

Core types and traits for the Model Context Protocol (MCP)
Documentation
//! Standard JSON-RPC and MCP error codes.
//!
//! This module defines error code constants used in JSON-RPC 2.0 responses
//! and MCP-specific error responses.

/// Invalid JSON was received.
pub const PARSE_ERROR: i32 = -32700;

/// The JSON sent is not a valid Request object.
pub const INVALID_REQUEST: i32 = -32600;

/// The method does not exist.
pub const METHOD_NOT_FOUND: i32 = -32601;

/// Invalid method parameters.
pub const INVALID_PARAMS: i32 = -32602;

/// Internal JSON-RPC error.
pub const INTERNAL_ERROR: i32 = -32603;

/// Server error range start.
pub const SERVER_ERROR_START: i32 = -32000;

/// Server error range end.
pub const SERVER_ERROR_END: i32 = -32099;

// MCP-specific codes

/// The user rejected the operation.
///
/// Spec-defined: the 2025-11-25 sampling flow names `-1` for
/// "User rejected sampling request". It sits outside the JSON-RPC reserved
/// range (-32768..-32000), so it is an application-level code by design.
pub const USER_REJECTED: i32 = -1;

/// Resource was not found.
pub const RESOURCE_NOT_FOUND: i32 = -32002;

/// The server requires a URL-mode elicitation before the request can proceed.
pub const URL_ELICITATION_REQUIRED: i32 = -32042;