gemini_adk_rs/tools/mcp/
session_manager.rs

1//! MCP session management — connection params, tool discovery, and tool invocation.
2
3use std::collections::HashMap;
4use std::time::Duration;
5
6/// Connection parameters for an MCP server.
7#[derive(Debug, Clone)]
8pub enum McpConnectionParams {
9    /// Connect via stdio (subprocess).
10    Stdio {
11        /// The command to execute.
12        command: String,
13        /// Arguments passed to the command.
14        args: Vec<String>,
15        /// Connection timeout.
16        timeout: Option<Duration>,
17    },
18    /// Connect via SSE/StreamableHTTP.
19    Sse {
20        /// The URL of the MCP server.
21        url: String,
22        /// Optional HTTP headers for authentication.
23        headers: Option<HashMap<String, String>>,
24    },
25}
26
27/// Manages the MCP client session lifecycle.
28pub struct McpSessionManager {
29    params: McpConnectionParams,
30}
31
32impl McpSessionManager {
33    /// Create a new MCP session manager with the given connection params.
34    pub fn new(params: McpConnectionParams) -> Self {
35        Self { params }
36    }
37
38    /// Get the connection parameters.
39    pub fn params(&self) -> &McpConnectionParams {
40        &self.params
41    }
42
43    /// List available tools from the MCP server.
44    /// Stub: returns empty list. Full implementation awaits MCP client integration.
45    pub async fn list_tools(&self) -> Result<Vec<McpToolInfo>, McpError> {
46        // TODO: Connect to MCP server and list tools
47        Ok(vec![])
48    }
49
50    /// Call a tool on the MCP server.
51    /// Stub: returns error. Full implementation awaits MCP client integration.
52    pub async fn call_tool(
53        &self,
54        name: &str,
55        _args: serde_json::Value,
56    ) -> Result<serde_json::Value, McpError> {
57        Err(McpError::NotConnected(format!(
58            "MCP session not connected — call_tool({}) requires MCP client integration",
59            name
60        )))
61    }
62}
63
64/// Information about an MCP tool.
65#[derive(Debug, Clone)]
66pub struct McpToolInfo {
67    /// Tool name.
68    pub name: String,
69    /// Human-readable tool description.
70    pub description: String,
71    /// JSON Schema for the tool's input parameters.
72    pub input_schema: serde_json::Value,
73}
74
75/// MCP-related errors.
76#[derive(Debug, thiserror::Error)]
77pub enum McpError {
78    /// Failed to connect to the MCP server.
79    #[error("Connection failed: {0}")]
80    ConnectionFailed(String),
81    /// The MCP session is not connected.
82    #[error("Not connected: {0}")]
83    NotConnected(String),
84    /// A tool call to the MCP server failed.
85    #[error("Tool call failed: {0}")]
86    ToolCallFailed(String),
87    /// A catch-all for other MCP errors.
88    #[error("{0}")]
89    Other(String),
90}
gemini_adk_rs/tools/mcp/session_manager.rs

gemini_adk_rs/tools/mcp/
session_manager.rs
