diff --git a/cli/src/agent/backends/acp/AcpSdkBackend.test.ts b/cli/src/agent/backends/acp/AcpSdkBackend.test.ts
index 59a0b45e0..8d70f0ccc 100644
--- a/cli/src/agent/backends/acp/AcpSdkBackend.test.ts
+++ b/cli/src/agent/backends/acp/AcpSdkBackend.test.ts
@@ -645,59 +645,6 @@ describe('AcpSdkBackend', () => {
         expect(turnCompleteIdx).toBeGreaterThan(stragglerIdx);
     });
 
-    it('emits a context-only usage mid-turn so the status bar updates live', async () => {
-        backendStatics.UPDATE_QUIET_PERIOD_MS = 25;
-        backendStatics.UPDATE_DRAIN_TIMEOUT_MS = 200;
-        backendStatics.PRE_PROMPT_UPDATE_QUIET_PERIOD_MS = 1;
-        backendStatics.PRE_PROMPT_UPDATE_DRAIN_TIMEOUT_MS = 50;
-        backendStatics.LATE_FLUSH_INTERVAL_MS = 5;
-        backendStatics.LATE_FLUSH_QUIET_PERIOD_MS = 10;
-        backendStatics.LATE_FLUSH_WINDOW_MS = 50;
-
-        const backend = new AcpSdkBackend({ command: 'opencode' });
-        const backendInternal = backend as unknown as {
-            transport: {
-                sendRequest: (...args: unknown[]) => Promise<unknown>;
-                close: () => Promise<void>;
-            } | null;
-            handleSessionUpdate: (params: unknown) => void;
-        };
-
-        const messages: AgentMessage[] = [];
-        backendInternal.transport = {
-            sendRequest: async () => {
-                backendInternal.handleSessionUpdate({
-                    sessionId: 'session-1',
-                    update: { sessionUpdate: 'usage_update', used: 1_000, size: 200_000 }
-                });
-                backendInternal.handleSessionUpdate({
-                    sessionId: 'session-1',
-                    update: { sessionUpdate: 'usage_update', used: 1_000, size: 200_000 }
-                });
-                backendInternal.handleSessionUpdate({
-                    sessionId: 'session-1',
-                    update: { sessionUpdate: 'usage_update', used: 2_500, size: 200_000 }
-                });
-                await sleep(5);
-                return {
-                    stopReason: 'end_turn',
-                    usage: { inputTokens: 100, outputTokens: 50 }
-                };
-            },
-            close: async () => {}
-        };
-
-        await backend.prompt('session-1', [{ type: 'text', text: 'hello' }], (m) => messages.push(m));
-
-        const usageMessages = messages.filter((m): m is Extract<AgentMessage, { type: 'usage' }> => m.type === 'usage');
-        // Two mid-turn ticks (deduped second 1_000) + one final emit with the
-        // prompt-level input/output totals.
-        expect(usageMessages.length).toBe(3);
-        expect(usageMessages[0]).toMatchObject({ inputTokens: 0, outputTokens: 0, contextTokens: 1_000, contextWindow: 200_000 });
-        expect(usageMessages[1]).toMatchObject({ inputTokens: 0, outputTokens: 0, contextTokens: 2_500, contextWindow: 200_000 });
-        expect(usageMessages[2]).toMatchObject({ inputTokens: 100, outputTokens: 50, contextTokens: 2_500, contextWindow: 200_000 });
-    });
-
     it('emits a context-only usage on finalize when the prompt response carries no usage', async () => {
         backendStatics.UPDATE_QUIET_PERIOD_MS = 25;
         backendStatics.UPDATE_DRAIN_TIMEOUT_MS = 200;
@@ -734,15 +681,12 @@ describe('AcpSdkBackend', () => {
         await backend.prompt('session-1', [{ type: 'text', text: 'hi' }], (m) => messages.push(m));
 
         const usageMessages = messages.filter((m): m is Extract<AgentMessage, { type: 'usage' }> => m.type === 'usage');
-        // One mid-turn emit and one finalize fallback — both context-only.
-        expect(usageMessages.length).toBe(2);
-        for (const usage of usageMessages) {
-            expect(usage).toMatchObject({
-                inputTokens: 0,
-                outputTokens: 0,
-                contextTokens: 4_200,
-                contextWindow: 200_000
-            });
-        }
+        expect(usageMessages.length).toBe(1);
+        expect(usageMessages[0]).toMatchObject({
+            inputTokens: 0,
+            outputTokens: 0,
+            contextTokens: 4_200,
+            contextWindow: 200_000
+        });
     });
 });
diff --git a/cli/src/agent/backends/acp/AcpSdkBackend.ts b/cli/src/agent/backends/acp/AcpSdkBackend.ts
index c7b0e41a4..8426e776e 100644
--- a/cli/src/agent/backends/acp/AcpSdkBackend.ts
+++ b/cli/src/agent/backends/acp/AcpSdkBackend.ts
@@ -55,7 +55,6 @@ export class AcpSdkBackend implements AgentBackend {
     private responseCompleteResolvers: Array<() => void> = [];
     private lastSessionUpdateAt = 0;
     private latestUsageUpdate: AcpUsageUpdate | null = null;
-    private activeOnUpdate: ((msg: AgentMessage) => void) | null = null;
 
     /** Retry configuration for ACP initialization */
     private static readonly INIT_RETRY_OPTIONS = {
@@ -284,7 +283,6 @@ export class AcpSdkBackend implements AgentBackend {
         );
         this.messageHandler?.drainBuffers();
         this.messageHandler = new AcpMessageHandler(onUpdate);
-        this.activeOnUpdate = onUpdate;
         this.isProcessingMessage = true;
         this.lastSessionUpdateAt = Date.now();
         this.latestUsageUpdate = null;
@@ -345,7 +343,6 @@ export class AcpSdkBackend implements AgentBackend {
                     onUpdate({ type: 'turn_complete', stopReason });
                 }
             } finally {
-                this.activeOnUpdate = null;
                 this.isProcessingMessage = false;
                 this.notifyResponseComplete();
             }
@@ -425,7 +422,6 @@ export class AcpSdkBackend implements AgentBackend {
         if (!this.transport) return;
         this.messageHandler?.drainBuffers();
         this.messageHandler = null;
-        this.activeOnUpdate = null;
         this.activeSessionId = null;
         this.isProcessingMessage = false;
         this.sessionModelsMetadata.clear();
@@ -450,32 +446,12 @@ export class AcpSdkBackend implements AgentBackend {
         if (!isObject(update)) return;
         if (asString(update.sessionUpdate) !== ACP_SESSION_UPDATE_TYPES.usageUpdate) return;
 
-        const contextTokens = this.asFiniteNumber(update.used) ?? undefined;
-        const contextWindow = this.asFiniteNumber(update.size) ?? undefined;
-        const prev = this.latestUsageUpdate;
-        const changed = !prev
-            || prev.contextTokens !== contextTokens
-            || prev.contextWindow !== contextWindow;
-        this.latestUsageUpdate = { contextTokens, contextWindow };
-
-        // Surface context updates mid-turn so the web status bar shows live
-        // ctx N/M (X%) instead of staying blank until the final prompt usage
-        // arrives. ACP usage_update only carries context tokens, so I/O is
-        // sent as 0; the final prompt-finalize emit overwrites with the real
-        // input/output totals.
-        if (
-            changed
-            && this.activeOnUpdate
-            && (contextTokens !== undefined || contextWindow !== undefined)
-        ) {
-            this.activeOnUpdate({
-                type: 'usage',
-                inputTokens: 0,
-                outputTokens: 0,
-                contextTokens,
-                contextWindow
-            });
-        }
+        const contextTokens = this.asFiniteNumber(update.used);
+        const contextWindow = this.asFiniteNumber(update.size);
+        this.latestUsageUpdate = {
+            contextTokens: contextTokens ?? undefined,
+            contextWindow: contextWindow ?? undefined
+        };
     }
 
     private readLatestUsageUpdate(): AcpUsageUpdate | null {