fix: fix OpenAPI build (#2036)

crates/mcp-core/Cargo.toml

@@ -13,6 +13,7 @@ anyhow = "1.0"
 chrono = { version = "0.4.38", features = ["serde"] }
 url = "2.5"
 base64 = "0.21"
+utoipa = "4.1"
 
 [dev-dependencies]
 tempfile = "3.8"

crates/mcp-core/src/tool.rs

@@ -2,6 +2,7 @@
 /// Tool calls represent requests from the client to execute one
 use serde::{Deserialize, Serialize};
 use serde_json::Value;
+use utoipa::ToSchema;
 
 /// Additional properties describing a tool to clients.
 ///
@@ -11,7 +12,7 @@ use serde_json::Value;
 ///
 /// Clients should never make tool use decisions based on ToolAnnotations
 /// received from untrusted servers.
-#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, ToSchema)]
 #[serde(rename_all = "camelCase")]
 pub struct ToolAnnotations {
     /// A human-readable title for the tool.
@@ -100,7 +101,7 @@ impl ToolAnnotations {
 }
 
 /// A tool that can be used by a model.
-#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, ToSchema)]
 #[serde(rename_all = "camelCase")]
 pub struct Tool {
     /// The name of the tool