diff --git a/src/gateway/server-methods/usage.sessions-usage.test.ts b/src/gateway/server-methods/usage.sessions-usage.test.ts
index c5c57f4ecda..db25201b481 100644
--- a/src/gateway/server-methods/usage.sessions-usage.test.ts
+++ b/src/gateway/server-methods/usage.sessions-usage.test.ts
@@ -189,6 +189,46 @@ describe("sessions.usage", () => {
     }
   });
 
+  it("prefers the deterministic store key when duplicate sessionIds exist", async () => {
+    const preferredKey = "agent:opus:acp:run-dup";
+    const stateDir = fs.mkdtempSync(path.join(os.tmpdir(), "openclaw-usage-test-"));
+
+    try {
+      await withEnvAsync({ OPENCLAW_STATE_DIR: stateDir }, async () => {
+        const agentSessionsDir = path.join(stateDir, "agents", "opus", "sessions");
+        fs.mkdirSync(agentSessionsDir, { recursive: true });
+        const sessionFile = path.join(agentSessionsDir, "run-dup.jsonl");
+        fs.writeFileSync(sessionFile, "", "utf-8");
+
+        vi.mocked(loadCombinedSessionStoreForGateway).mockReturnValue({
+          storePath: "(multiple)",
+          store: {
+            [preferredKey]: {
+              sessionId: "run-dup",
+              sessionFile: "run-dup.jsonl",
+              updatedAt: 1_000,
+            },
+            "agent:other:main": {
+              sessionId: "run-dup",
+              sessionFile: "run-dup.jsonl",
+              updatedAt: 2_000,
+            },
+          },
+        });
+
+        const respond = await runSessionsUsage({
+          ...BASE_USAGE_RANGE,
+          key: "agent:opus:run-dup",
+        });
+        const sessions = expectSuccessfulSessionsUsage(respond);
+        expect(sessions).toHaveLength(1);
+        expect(sessions[0]?.key).toBe(preferredKey);
+      });
+    } finally {
+      fs.rmSync(stateDir, { recursive: true, force: true });
+    }
+  });
+
   it("rejects traversal-style keys in specific session usage lookups", async () => {
     const respond = await runSessionsUsage({
       ...BASE_USAGE_RANGE,
diff --git a/src/gateway/server-methods/usage.ts b/src/gateway/server-methods/usage.ts
index 8298f34eb24..83e96083f65 100644
--- a/src/gateway/server-methods/usage.ts
+++ b/src/gateway/server-methods/usage.ts
@@ -21,6 +21,7 @@ import {
   type DiscoveredSession,
 } from "../../infra/session-cost-usage.js";
 import { parseAgentSessionKey } from "../../routing/session-key.js";
+import { resolvePreferredSessionKeyForSessionIdMatches } from "../../sessions/session-id-resolution.js";
 import {
   buildUsageAggregateTail,
   mergeUsageDailyLatency,
@@ -252,10 +253,25 @@ type DiscoveredSessionWithAgent = DiscoveredSession & { agentId: string };
 function buildStoreBySessionId(
   store: Record<string, SessionEntry>,
 ): Map<string, { key: string; entry: SessionEntry }> {
-  const storeBySessionId = new Map<string, { key: string; entry: SessionEntry }>();
+  const matchesBySessionId = new Map<string, Array<[string, SessionEntry]>>();
   for (const [key, entry] of Object.entries(store)) {
-    if (entry?.sessionId) {
-      storeBySessionId.set(entry.sessionId, { key, entry });
+    if (!entry?.sessionId) {
+      continue;
+    }
+    const matches = matchesBySessionId.get(entry.sessionId) ?? [];
+    matches.push([key, entry]);
+    matchesBySessionId.set(entry.sessionId, matches);
+  }
+
+  const storeBySessionId = new Map<string, { key: string; entry: SessionEntry }>();
+  for (const [sessionId, matches] of matchesBySessionId) {
+    const preferredKey = resolvePreferredSessionKeyForSessionIdMatches(matches, sessionId);
+    if (!preferredKey) {
+      continue;
+    }
+    const preferredEntry = store[preferredKey];
+    if (preferredEntry) {
+      storeBySessionId.set(sessionId, { key: preferredKey, entry: preferredEntry });
     }
   }
   return storeBySessionId;