feat: Allow cancellation of in-progress Gemini requests and pre-execution checks

- Implements cancellation for Gemini requests while they are actively being processed by the model.
- Extends cancellation support to the  logic within tools. This allows users to cancel operations during the phase where the system is determining if a tool execution requires user confirmation, which can include potentially long-running pre-flight checks or LLM-based corrections.
- Underlying LLM calls for edit corrections (within  and ) and next speaker checks can now also be cancelled.
- Previously, cancellation of the main request was not possible until text started streaming, and pre-execution checks were not cancellable.
- This change leverages the updated SDK's ability to accept an abort token and threads s throughout the request, tool execution, and pre-execution check lifecycle.

Fixes https://github.com/google-gemini/gemini-cli/issues/531

1 files changed, 11 insertions, 1 deletions

diff --git a/packages/server/src/core/turn.ts b/packages/server/src/core/turn.ts
index d5c7eb58..97e93f59 100644
--- a/packages/server/src/core/turn.ts
+++ b/packages/server/src/core/turn.ts
@@ -32,6 +32,7 @@ export interface ServerTool {
   ): Promise<ToolResult>;
   shouldConfirmExecute(
     params: Record<string, unknown>,
+    abortSignal: AbortSignal,
   ): Promise<ToolCallConfirmationDetails | false>;
 }
 
@@ -120,11 +121,14 @@ export class Turn {
   // The run method yields simpler events suitable for server logic
   async *run(
     req: PartListUnion,
-    signal?: AbortSignal,
+    signal: AbortSignal,
   ): AsyncGenerator<ServerGeminiStreamEvent> {
     try {
       const responseStream = await this.chat.sendMessageStream({
         message: req,
+        config: {
+          abortSignal: signal,
+        },
       });
 
       for await (const resp of responseStream) {
@@ -150,6 +154,12 @@ export class Turn {
         }
       }
     } catch (error) {
+      if (signal.aborted) {
+        yield { type: GeminiEventType.UserCancelled };
+        // Regular cancellation error, fail gracefully.
+        return;
+      }
+
       const contextForReport = [...this.chat.getHistory(/*curated*/ true), req];
       await reportError(
         error,