inline assistant: Use tools and remove insertion mode (#44248)

Co-authored by: Mikayla Maki <mikayla.c.maki@gmail.com>
Co-authored-by: Danilo Leal <daniloleal09@gmail.com>

Release Notes:

- N/A

crates/language_model/src/language_model.rs

@@ -707,6 +707,40 @@ pub trait LanguageModel: Send + Sync {
         .boxed()
     }
 
+    fn stream_completion_tool(
+        &self,
+        request: LanguageModelRequest,
+        cx: &AsyncApp,
+    ) -> BoxFuture<'static, Result<LanguageModelToolUse, LanguageModelCompletionError>> {
+        let future = self.stream_completion(request, cx);
+
+        async move {
+            let events = future.await?;
+            let mut events = events.fuse();
+
+            // Iterate through events until we find a complete ToolUse
+            while let Some(event) = events.next().await {
+                match event {
+                    Ok(LanguageModelCompletionEvent::ToolUse(tool_use))
+                        if tool_use.is_input_complete =>
+                    {
+                        return Ok(tool_use);
+                    }
+                    Err(err) => {
+                        return Err(err);
+                    }
+                    _ => {}
+                }
+            }
+
+            // Stream ended without a complete tool use
+            Err(LanguageModelCompletionError::Other(anyhow::anyhow!(
+                "Stream ended without receiving a complete tool use"
+            )))
+        }
+        .boxed()
+    }
+
     fn cache_configuration(&self) -> Option<LanguageModelCacheConfiguration> {
         None
     }