From 4739495e39ebe216b126c53e0a790f563649420f Mon Sep 17 00:00:00 2001
From: Sri Pasumarthi <111310667+sripasg@users.noreply.github.com>
Date: Mon, 11 May 2026 10:38:20 -0700
Subject: [PATCH] fix(cli/acp): prevent infinite thought loop in ACP mode by
 disablig nextSpeakerCheck (#26874)

---
 packages/cli/src/config/config.test.ts | 22 ++++++++++++++++++++++
 packages/cli/src/config/config.ts      |  6 +++++-
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/packages/cli/src/config/config.test.ts b/packages/cli/src/config/config.test.ts
index e2c223b55c..fd1e0a4de9 100644
--- a/packages/cli/src/config/config.test.ts
+++ b/packages/cli/src/config/config.test.ts
@@ -1043,6 +1043,28 @@ describe('loadCliConfig', () => {
 
     expect(config.isInteractive()).toBe(false);
   });
+
+  describe('isAcpMode', () => {
+    it('should force skipNextSpeakerCheck to true when in ACP mode', async () => {
+      process.argv = ['node', 'script.js', '--acp'];
+      const argv = await parseArguments(createTestMergedSettings());
+      const settings = createTestMergedSettings({
+        model: { skipNextSpeakerCheck: false },
+      });
+      const config = await loadCliConfig(settings, 'test-session', argv);
+      expect(config.getSkipNextSpeakerCheck()).toBe(true);
+    });
+
+    it('should respect settings.model.skipNextSpeakerCheck when not in ACP mode', async () => {
+      process.argv = ['node', 'script.js'];
+      const argv = await parseArguments(createTestMergedSettings());
+      const settings = createTestMergedSettings({
+        model: { skipNextSpeakerCheck: false },
+      });
+      const config = await loadCliConfig(settings, 'test-session', argv);
+      expect(config.getSkipNextSpeakerCheck()).toBe(false);
+    });
+  });
 });
 
 describe('Hierarchical Memory Loading (config.ts) - Placeholder Suite', () => {
diff --git a/packages/cli/src/config/config.ts b/packages/cli/src/config/config.ts
index d683084413..e7b332711d 100755
--- a/packages/cli/src/config/config.ts
+++ b/packages/cli/src/config/config.ts
@@ -1105,7 +1105,11 @@ export async function loadCliConfig(
     shellToolInactivityTimeout: settings.tools?.shell?.inactivityTimeout,
     enableShellOutputEfficiency:
       settings.tools?.shell?.enableShellOutputEfficiency ?? true,
-    skipNextSpeakerCheck: settings.model?.skipNextSpeakerCheck,
+    // In ACP mode, always skip the next-speaker check. This check triggers
+    // recursive continuation turns inside GeminiClient.processTurn() that
+    // conflict with ACP's explicit turn management via session/prompt,
+    // causing infinite agent_thought_chunk loops.
+    skipNextSpeakerCheck: isAcpMode || settings.model?.skipNextSpeakerCheck,
     truncateToolOutputThreshold: settings.tools?.truncateToolOutputThreshold,
     eventEmitter: coreEvents,
     useWriteTodos: argv.useWriteTodos ?? settings.useWriteTodos,