Trait McpService 

pub trait McpService: Send + Sync {
    // Required methods
    fn list_tools(
        &self,
    ) -> Pin<Box<dyn Future<Output = Result<Vec<ToolDefinition>, McpError>> + Send + '_>>;
    fn call_tool(
        &self,
        name: &str,
        args: Value,
    ) -> Pin<Box<dyn Future<Output = Result<String, McpError>> + Send + '_>>;
}

Minimal contract for MCP-like tool sources.

Implement this trait to bridge any MCP client library with llm-core’s tool system. The trait requires only two operations:

1. List available tools (with their schemas)
2. Call a tool by name with JSON arguments

Thread Safety

Implementations must be Send + Sync to allow use across async tasks. Typically achieved by wrapping the underlying client in Arc.

Object Safety

This trait is object-safe (dyn McpService) to allow storing different MCP service implementations in the same registry.

Required Methods

fn list_tools( &self, ) -> Pin<Box<dyn Future<Output = Result<Vec<ToolDefinition>, McpError>> + Send + '_>>

Lists all tools available from the MCP server.

fn call_tool( &self, name: &str, args: Value, ) -> Pin<Box<dyn Future<Output = Result<String, McpError>> + Send + '_>>

Calls a tool on the MCP server.

Arguments

• name - The name of the tool to call
• args - JSON arguments matching the tool’s input schema

Returns

The tool’s text output, or an error if execution failed.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors