vestige/crates/vestige-mcp/src/protocol/messages.rs

//! MCP Protocol Messages
//!
//! Request and response types for MCP methods.

use serde::{Deserialize, Serialize};
use serde_json::Value;
use std::collections::HashMap;

// ============================================================================
// INITIALIZE
// ============================================================================

/// Initialize request from client
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct InitializeRequest {
    pub protocol_version: String,
    pub capabilities: ClientCapabilities,
    pub client_info: ClientInfo,
}

impl Default for InitializeRequest {
    fn default() -> Self {
        Self {
            protocol_version: "2024-11-05".to_string(),
            capabilities: ClientCapabilities::default(),
            client_info: ClientInfo {
                name: "unknown".to_string(),
                version: "0.0.0".to_string(),
            },
        }
    }
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct ClientCapabilities {
    #[serde(skip_serializing_if = "Option::is_none")]
    pub roots: Option<HashMap<String, Value>>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub sampling: Option<HashMap<String, Value>>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct ClientInfo {
    pub name: String,
    pub version: String,
}

/// Initialize response to client
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct InitializeResult {
    pub protocol_version: String,
    pub server_info: ServerInfo,
    pub capabilities: ServerCapabilities,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub instructions: Option<String>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct ServerInfo {
    pub name: String,
    pub version: String,
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct ServerCapabilities {
    #[serde(skip_serializing_if = "Option::is_none")]
    pub tools: Option<HashMap<String, Value>>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub resources: Option<HashMap<String, Value>>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub prompts: Option<HashMap<String, Value>>,
}

// ============================================================================
// TOOLS
// ============================================================================

/// Tool description for tools/list
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct ToolDescription {
    pub name: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub description: Option<String>,
    pub input_schema: Value,
}

/// Result of tools/list
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct ListToolsResult {
    pub tools: Vec<ToolDescription>,
}

/// Request for tools/call
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct CallToolRequest {
    pub name: String,
    #[serde(default)]
    pub arguments: Option<Value>,
}

/// Result of tools/call
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct CallToolResult {
    pub content: Vec<ToolResultContent>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub is_error: Option<bool>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct ToolResultContent {
    #[serde(rename = "type")]
    pub content_type: String,
    pub text: String,
}

// ============================================================================
// RESOURCES
// ============================================================================

/// Resource description for resources/list
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct ResourceDescription {
    pub uri: String,
    pub name: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub description: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub mime_type: Option<String>,
}

/// Result of resources/list
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct ListResourcesResult {
    pub resources: Vec<ResourceDescription>,
}

/// Request for resources/read
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct ReadResourceRequest {
    pub uri: String,
}

/// Result of resources/read
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct ReadResourceResult {
    pub contents: Vec<ResourceContent>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct ResourceContent {
    pub uri: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub mime_type: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub text: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub blob: Option<String>,
}