diff --git a/packages/core/src/agents/local-executor.ts b/packages/core/src/agents/local-executor.ts
index 513424ad32a..f37cd58fc47 100644
--- a/packages/core/src/agents/local-executor.ts
+++ b/packages/core/src/agents/local-executor.ts
@@ -239,7 +239,7 @@ export class LocalAgentExecutor<TOutput extends z.ZodTypeAny> {
   ): Promise<AgentTurnResult> {
     const promptId = `${this.agentId}#${turnCounter}`;
 
-    await this.tryCompressChat(chat, promptId);
+    await this.tryCompressChat(chat, promptId, combinedSignal);
 
     const { functionCalls } = await promptIdContext.run(promptId, async () =>
       this.callModel(chat, currentMessage, combinedSignal, promptId),
@@ -668,6 +668,7 @@ export class LocalAgentExecutor<TOutput extends z.ZodTypeAny> {
   private async tryCompressChat(
     chat: GeminiChat,
     prompt_id: string,
+    abortSignal: AbortSignal,
   ): Promise<void> {
     const model = this.definition.modelConfig.model ?? DEFAULT_GEMINI_MODEL;
 
@@ -678,6 +679,7 @@ export class LocalAgentExecutor<TOutput extends z.ZodTypeAny> {
       model,
       this.runtimeContext,
       this.hasFailedCompressionAttempt,
+      abortSignal,
     );
 
     if (
diff --git a/packages/core/src/core/client.ts b/packages/core/src/core/client.ts
index c94dd5c04d0..9f1ce6c2ac0 100644
--- a/packages/core/src/core/client.ts
+++ b/packages/core/src/core/client.ts
@@ -574,7 +574,7 @@ export class GeminiClient {
     // Check for context window overflow
     const modelForLimitCheck = this._getActiveModelForCurrentTurn();
 
-    const compressed = await this.tryCompressChat(prompt_id, false);
+    const compressed = await this.tryCompressChat(prompt_id, false, signal);
 
     if (compressed.compressionStatus === CompressionStatus.COMPRESSED) {
       yield { type: GeminiEventType.ChatCompressed, value: compressed };
@@ -1049,12 +1049,17 @@ export class GeminiClient {
   async tryCompressChat(
     prompt_id: string,
     force: boolean = false,
+    abortSignal?: AbortSignal,
   ): Promise<ChatCompressionInfo> {
     // If the model is 'auto', we will use a placeholder model to check.
     // Compression occurs before we choose a model, so calling `count_tokens`
     // before the model is chosen would result in an error.
     const model = this._getActiveModelForCurrentTurn();
 
+    // Use the provided signal, or create a no-op signal as a fallback for
+    // callers that don't have one (e.g. the /compress command).
+    const signal = abortSignal ?? new AbortController().signal;
+
     const { newHistory, info } = await this.compressionService.compress(
       this.getChat(),
       prompt_id,
@@ -1062,6 +1067,7 @@ export class GeminiClient {
       model,
       this.config,
       this.hasFailedCompressionAttempt,
+      signal,
     );
 
     if (
diff --git a/packages/core/src/services/chatCompressionService.test.ts b/packages/core/src/services/chatCompressionService.test.ts
index 4ddd38e25cb..4bb42b9ff71 100644
--- a/packages/core/src/services/chatCompressionService.test.ts
+++ b/packages/core/src/services/chatCompressionService.test.ts
@@ -138,6 +138,7 @@ describe('ChatCompressionService', () => {
   let testTempDir: string;
   const mockModel = 'gemini-2.5-pro';
   const mockPromptId = 'test-prompt-id';
+  const mockAbortSignal = new AbortController().signal;
 
   beforeEach(() => {
     testTempDir = fs.mkdtempSync(
@@ -211,6 +212,7 @@ describe('ChatCompressionService', () => {
       mockModel,
       mockConfig,
       false,
+      mockAbortSignal,
     );
     expect(result.info.compressionStatus).toBe(CompressionStatus.NOOP);
     expect(result.newHistory).toBeNull();
@@ -227,6 +229,7 @@ describe('ChatCompressionService', () => {
       mockModel,
       mockConfig,
       false,
+      mockAbortSignal,
     );
     // It should now attempt compression even if previously failed (logic removed)
     // But since history is small, it will be NOOP due to threshold
@@ -253,6 +256,7 @@ describe('ChatCompressionService', () => {
       mockModel,
       mockConfig,
       false,
+      mockAbortSignal,
     );
     expect(result.info.compressionStatus).toBe(CompressionStatus.NOOP);
     expect(result.newHistory).toBeNull();
@@ -276,6 +280,7 @@ describe('ChatCompressionService', () => {
       mockModel,
       mockConfig,
       false,
+      mockAbortSignal,
     );
 
     expect(result.info.compressionStatus).toBe(CompressionStatus.COMPRESSED);
@@ -317,6 +322,7 @@ describe('ChatCompressionService', () => {
       mockModel,
       mockConfig,
       false,
+      mockAbortSignal,
     );
 
     expect(result.info.compressionStatus).toBe(CompressionStatus.COMPRESSED);
@@ -344,6 +350,7 @@ describe('ChatCompressionService', () => {
       mockModel,
       mockConfig,
       false,
+      mockAbortSignal,
     );
 
     const firstCall = vi.mocked(mockConfig.getBaseLlmClient().generateContent)
@@ -371,6 +378,7 @@ describe('ChatCompressionService', () => {
       mockModel,
       mockConfig,
       false,
+      mockAbortSignal,
     );
 
     expect(result.info.compressionStatus).toBe(CompressionStatus.COMPRESSED);
@@ -408,6 +416,7 @@ describe('ChatCompressionService', () => {
       mockModel,
       mockConfig,
       false,
+      mockAbortSignal,
     );
 
     expect(result.info.compressionStatus).toBe(
@@ -448,6 +457,7 @@ describe('ChatCompressionService', () => {
       mockModel,
       mockConfig,
       false,
+      mockAbortSignal,
     );
 
     expect(result.info.compressionStatus).toBe(
@@ -504,6 +514,7 @@ describe('ChatCompressionService', () => {
         mockModel,
         mockConfig,
         false,
+        mockAbortSignal,
       );
 
       expect(result.info.compressionStatus).toBe(CompressionStatus.COMPRESSED);
@@ -570,6 +581,7 @@ describe('ChatCompressionService', () => {
         mockModel,
         mockConfig,
         false,
+        mockAbortSignal,
       );
 
       // Verify it compressed
@@ -636,6 +648,7 @@ describe('ChatCompressionService', () => {
         mockModel,
         mockConfig,
         false,
+        mockAbortSignal,
       );
 
       expect(result.newHistory).not.toBeNull();
@@ -703,6 +716,7 @@ describe('ChatCompressionService', () => {
         mockModel,
         mockConfig,
         false,
+        mockAbortSignal,
       );
 
       expect(result.info.compressionStatus).toBe(CompressionStatus.COMPRESSED);
@@ -760,6 +774,7 @@ describe('ChatCompressionService', () => {
         mockModel,
         mockConfig,
         false,
+        mockAbortSignal,
       );
 
       expect(result.info.compressionStatus).toBe(CompressionStatus.COMPRESSED);
@@ -817,6 +832,7 @@ describe('ChatCompressionService', () => {
         mockModel,
         mockConfig,
         false,
+        mockAbortSignal,
       );
 
       expect(result.info.compressionStatus).toBe(CompressionStatus.COMPRESSED);
diff --git a/packages/core/src/services/chatCompressionService.ts b/packages/core/src/services/chatCompressionService.ts
index 5303a1a82a8..90549c01b0c 100644
--- a/packages/core/src/services/chatCompressionService.ts
+++ b/packages/core/src/services/chatCompressionService.ts
@@ -236,7 +236,7 @@ export class ChatCompressionService {
     model: string,
     config: Config,
     hasFailedCompressionAttempt: boolean,
-    abortSignal?: AbortSignal,
+    abortSignal: AbortSignal,
   ): Promise<{ newHistory: Content[] | null; info: ChatCompressionInfo }> {
     const curatedHistory = chat.getHistory(true);
 
@@ -365,8 +365,7 @@ export class ChatCompressionService {
       ],
       systemInstruction: { text: getCompressionPrompt(config) },
       promptId,
-      // TODO(joshualitt): wire up a sensible abort signal,
-      abortSignal: abortSignal ?? new AbortController().signal,
+      abortSignal,
       role: LlmRole.UTILITY_COMPRESSOR,
     });
     const summary = getResponseText(summaryResponse) ?? '';
@@ -395,7 +394,7 @@ export class ChatCompressionService {
         systemInstruction: { text: getCompressionPrompt(config) },
         promptId: `${promptId}-verify`,
         role: LlmRole.UTILITY_COMPRESSOR,
-        abortSignal: abortSignal ?? new AbortController().signal,
+        abortSignal,
       });
 
     const finalSummary = (