diff --git a/extensions/copilot/src/usage-bridge.test.ts b/extensions/copilot/src/usage-bridge.test.ts
index 680b07088e24..cb67cbf3cdbf 100644
--- a/extensions/copilot/src/usage-bridge.test.ts
+++ b/extensions/copilot/src/usage-bridge.test.ts
@@ -3,7 +3,6 @@ import type { NormalizedUsage } from "openclaw/plugin-sdk/agent-harness-runtime"
 import { describe, expect, it } from "vitest";
 import {
   buildCopilotAssistantUsage,
-  deriveCopilotUsageTotal,
   normalizeCopilotUsage,
 } from "./usage-bridge.js";
 
@@ -251,21 +250,4 @@ describe("usage-bridge", () => {
     });
   });
 
-  describe("deriveCopilotUsageTotal", () => {
-    it("returns undefined when usage is undefined", () => {
-      expect(deriveCopilotUsageTotal(undefined)).toBeUndefined();
-    });
-
-    it("sums input/output/cacheRead/cacheWrite for total", () => {
-      const usage: NormalizedUsage = {
-        cacheRead: 3,
-        cacheWrite: 4,
-        input: 1,
-        output: 2,
-        total: 999,
-      };
-
-      expect(deriveCopilotUsageTotal(usage)).toBe(10);
-    });
-  });
 });
diff --git a/extensions/copilot/src/usage-bridge.ts b/extensions/copilot/src/usage-bridge.ts
index 2fadfdb38336..2d98659d758c 100644
--- a/extensions/copilot/src/usage-bridge.ts
+++ b/extensions/copilot/src/usage-bridge.ts
@@ -72,13 +72,3 @@ export function buildCopilotAssistantUsage(params: {
     totalTokens: usage?.total ?? 0,
   };
 }
-
-export function deriveCopilotUsageTotal(usage?: NormalizedUsage): number | undefined {
-  if (!usage) {
-    return undefined;
-  }
-
-  return (
-    (usage.input ?? 0) + (usage.output ?? 0) + (usage.cacheRead ?? 0) + (usage.cacheWrite ?? 0)
-  );
-}