5 files changed, 30 insertions, 11 deletions
diff --git a/packages/cli/src/ui/components/messages/CompressionMessage.tsx b/packages/cli/src/ui/components/messages/CompressionMessage.tsx
index aaa56149..d1080668 100644
--- a/packages/cli/src/ui/components/messages/CompressionMessage.tsx
+++ b/packages/cli/src/ui/components/messages/CompressionMessage.tsx
@@ -23,7 +23,8 @@ export const CompressionMessage: React.FC<CompressionDisplayProps> = ({
 }) => {
   const text = compression.isPending
     ? 'Compressing chat history'
-    : `Chat history compressed from ${compression.originalTokenCount} to ${compression.newTokenCount} tokens.`;
+    : `Chat history compressed from ${compression.originalTokenCount ?? 'unknown'}` +
+      ` to ${compression.newTokenCount ?? 'unknown'} tokens.`;
 
   return (
     <Box flexDirection="row">
diff --git a/packages/cli/src/ui/hooks/slashCommandProcessor.test.ts b/packages/cli/src/ui/hooks/slashCommandProcessor.test.ts
index 68dc3ea9..2eec29ca 100644
--- a/packages/cli/src/ui/hooks/slashCommandProcessor.test.ts
+++ b/packages/cli/src/ui/hooks/slashCommandProcessor.test.ts
@@ -159,8 +159,8 @@ describe('useSlashCommandProcessor', () => {
     process.env = { ...globalThis.process.env };
   });
 
-  const getProcessor = (showToolDescriptions: boolean = false) => {
-    const { result } = renderHook(() =>
+  const getProcessorHook = (showToolDescriptions: boolean = false) =>
+    renderHook(() =>
       useSlashCommandProcessor(
         mockConfig,
         [],
@@ -178,8 +178,9 @@ describe('useSlashCommandProcessor', () => {
         mockSetQuittingMessages,
       ),
     );
-    return result.current;
-  };
+
+  const getProcessor = (showToolDescriptions: boolean = false) =>
+    getProcessorHook(showToolDescriptions).result.current;
 
   describe('/memory add', () => {
     it('should return tool scheduling info on valid input', async () => {
@@ -1132,10 +1133,20 @@ Add any other context about the problem here.
 
   describe('/compress command', () => {
     it('should call tryCompressChat(true)', async () => {
-      const { handleSlashCommand } = getProcessor();
+      const hook = getProcessorHook();
       mockTryCompressChat.mockImplementationOnce(async (force?: boolean) => {
-        // TODO: Check that we have a pending compression item in the history.
         expect(force).toBe(true);
+        await act(async () => {
+          hook.rerender();
+        });
+        expect(hook.result.current.pendingHistoryItems).toContainEqual({
+          type: MessageType.COMPRESSION,
+          compression: {
+            isPending: true,
+            originalTokenCount: null,
+            newTokenCount: null,
+          },
+        });
         return {
           originalTokenCount: 100,
           newTokenCount: 50,
@@ -1143,8 +1154,12 @@ Add any other context about the problem here.
       });
 
       await act(async () => {
-        handleSlashCommand('/compress');
+        hook.result.current.handleSlashCommand('/compress');
+      });
+      await act(async () => {
+        hook.rerender();
       });
+      expect(hook.result.current.pendingHistoryItems).toEqual([]);
       expect(mockGeminiClient.tryCompressChat).toHaveBeenCalledWith(true);
       expect(mockAddItem).toHaveBeenNthCalledWith(
         2,
diff --git a/packages/cli/src/ui/hooks/slashCommandProcessor.ts b/packages/cli/src/ui/hooks/slashCommandProcessor.ts
index 916af3e7..8303ea55 100644
--- a/packages/cli/src/ui/hooks/slashCommandProcessor.ts
+++ b/packages/cli/src/ui/hooks/slashCommandProcessor.ts
@@ -760,6 +760,8 @@ Add any other context about the problem here.
             type: MessageType.COMPRESSION,
             compression: {
               isPending: true,
+              originalTokenCount: null,
+              newTokenCount: null,
             },
           });
           try {
diff --git a/packages/cli/src/ui/hooks/useGeminiStream.ts b/packages/cli/src/ui/hooks/useGeminiStream.ts
index d2153edf..6d92af0d 100644
--- a/packages/cli/src/ui/hooks/useGeminiStream.ts
+++ b/packages/cli/src/ui/hooks/useGeminiStream.ts
@@ -379,7 +379,8 @@ export const useGeminiStream = (
           text:
             `IMPORTANT: This conversation approached the input token limit for ${config.getModel()}. ` +
             `A compressed context will be sent for future messages (compressed from: ` +
-            `${eventValue.originalTokenCount} to ${eventValue.newTokenCount} tokens).`,
+            `${eventValue?.originalTokenCount ?? 'unknown'} to ` +
+            `${eventValue?.newTokenCount ?? 'unknown'} tokens).`,
         },
         Date.now(),
       ),
diff --git a/packages/cli/src/ui/types.ts b/packages/cli/src/ui/types.ts
index 3c0ec616..5cf372b4 100644
--- a/packages/cli/src/ui/types.ts
+++ b/packages/cli/src/ui/types.ts
@@ -55,8 +55,8 @@ export interface IndividualToolCallDisplay {
 
 export interface CompressionProps {
   isPending: boolean;
-  originalTokenCount?: number;
-  newTokenCount?: number;
+  originalTokenCount: number | null;
+  newTokenCount: number | null;
 }
 
 export interface HistoryItemBase {