feat: add client tool search support

ARCHITECTURE.md

@@ -198,7 +198,7 @@ access happen — those live in `tool/`, `executor/`, and `storage/` respectivel
   (the normalized `FunctionTool` and `ToolChoice`, distinct from tool *declarations*),
   `usage.rs` (token accounting structs).
 - **`types/tools/params.rs`** — the tool **declaration** shapes a client sends:
-  `ResponsesTool` (tagged enum: `Function`, `Mcp`, `WebSearch`, `FileSearch`,
+  `ResponsesTool` (tagged enum: `Function`, `ToolSearch`, `Mcp`, `WebSearch`, `FileSearch`,
   `CodeInterpreter`, `Namespace`, `Custom`, `Unknown`) and each variant's param struct.
   This is a good concrete example of the module boundary: `ResponsesTool` is *defined*
   here as a pure shape, but its behavior — `validate()` and `to_function_tools()` — is

crates/agentic-server-core/src/events/normalize.rs

@@ -108,6 +108,9 @@ fn extract_output_item_added(json: &Value) -> EventPayload {
         name: json_str_opt(item, "name"),
         namespace: json_str_opt(item, "namespace"),
         call_id: json_str_opt(item, "call_id"),
+        execution: item.get("execution").cloned().and_then(deserialize_from_value_opt),
+        status: json_str_opt(item, "status"),
+        arguments: item.get("arguments").and_then(Value::as_object).cloned(),
     }
 }
 

crates/agentic-server-core/src/events/types.rs

@@ -2,6 +2,7 @@ use serde::{Deserialize, Serialize};
 use serde_json::{Map, Value};
 
 use crate::types::io::ResponseUsage;
+use crate::types::tools::ToolSearchExecution;
 
 /// The type of an output item received during streaming.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -12,6 +13,7 @@ pub enum SSEItemType {
     WebSearchCall,
     McpCall,
     McpListTools,
+    ToolSearchCall,
     Compaction,
     Message,
 }
@@ -26,6 +28,7 @@ impl SSEItemType {
             Self::WebSearchCall => "web_search_call",
             Self::McpCall => "mcp_call",
             Self::McpListTools => "mcp_list_tools",
+            Self::ToolSearchCall => "tool_search_call",
             Self::Compaction => "compaction",
             Self::Message => "message",
         }
@@ -41,6 +44,7 @@ impl From<&str> for SSEItemType {
             "web_search_call" => Self::WebSearchCall,
             "mcp_call" => Self::McpCall,
             "mcp_list_tools" => Self::McpListTools,
+            "tool_search_call" => Self::ToolSearchCall,
             "compaction" => Self::Compaction,
             _ => Self::Message,
         }
@@ -252,6 +256,9 @@ pub enum EventPayload {
         name: Option<String>,
         namespace: Option<String>,
         call_id: Option<String>,
+        execution: Option<ToolSearchExecution>,
+        status: Option<String>,
+        arguments: Option<Map<String, Value>>,
     },
 
     /// `response.output_item.done`