diff --git a/src/gateway/server-methods/sessions.ts b/src/gateway/server-methods/sessions.ts
index 967fe633d57..b720b17f079 100644
--- a/src/gateway/server-methods/sessions.ts
+++ b/src/gateway/server-methods/sessions.ts
@@ -40,6 +40,7 @@ import {
   archiveFileOnDisk,
   listSessionsFromStore,
   loadCombinedSessionStoreForGateway,
+  loadGatewaySessionRow,
   loadSessionEntry,
   pruneLegacyStoreKeys,
   readSessionPreviewItemsFromTranscript,
@@ -117,11 +118,26 @@ function emitSessionsChanged(
   if (connIds.size === 0) {
     return;
   }
+  const sessionRow = payload.sessionKey ? loadGatewaySessionRow(payload.sessionKey) : null;
   context.broadcastToConnIds(
     "sessions.changed",
     {
       ...payload,
       ts: Date.now(),
+      ...(sessionRow
+        ? {
+            totalTokens: sessionRow.totalTokens,
+            totalTokensFresh: sessionRow.totalTokensFresh,
+            contextTokens: sessionRow.contextTokens,
+            estimatedCostUsd: sessionRow.estimatedCostUsd,
+            modelProvider: sessionRow.modelProvider,
+            model: sessionRow.model,
+            status: sessionRow.status,
+            startedAt: sessionRow.startedAt,
+            endedAt: sessionRow.endedAt,
+            runtimeMs: sessionRow.runtimeMs,
+          }
+        : {}),
     },
     connIds,
     { dropIfSlow: true },
diff --git a/src/gateway/server.sessions.gateway-server-sessions-a.test.ts b/src/gateway/server.sessions.gateway-server-sessions-a.test.ts
index 48ff50231ea..dd8719f0ba8 100644
--- a/src/gateway/server.sessions.gateway-server-sessions-a.test.ts
+++ b/src/gateway/server.sessions.gateway-server-sessions-a.test.ts
@@ -5,6 +5,7 @@ import { afterAll, beforeAll, beforeEach, describe, expect, test, vi } from "vit
 import { WebSocket } from "ws";
 import { DEFAULT_PROVIDER } from "../agents/defaults.js";
 import { GATEWAY_CLIENT_IDS, GATEWAY_CLIENT_MODES } from "./protocol/client-info.js";
+import { sessionsHandlers } from "./server-methods/sessions.js";
 import { startGatewayServerHarness, type GatewayServerHarness } from "./server.e2e-ws-harness.js";
 import { createToolSummaryPreviewTranscriptLines } from "./session-preview.test-helpers.js";
 import {
@@ -447,6 +448,84 @@ describe("gateway server sessions", () => {
     ws.close();
   });
 
+  test("sessions.changed mutation events include live usage metadata", async () => {
+    const { dir } = await createSessionStoreDir();
+    await fs.writeFile(
+      path.join(dir, "sess-main.jsonl"),
+      [
+        JSON.stringify({ type: "session", version: 1, id: "sess-main" }),
+        JSON.stringify({
+          id: "msg-usage-zero",
+          message: {
+            role: "assistant",
+            provider: "openai-codex",
+            model: "gpt-5.3-codex-spark",
+            usage: {
+              input: 5_107,
+              output: 1_827,
+              cacheRead: 1_536,
+              cacheWrite: 0,
+              cost: { total: 0 },
+            },
+            timestamp: Date.now(),
+          },
+        }),
+      ].join("\n"),
+      "utf-8",
+    );
+    await writeSessionStore({
+      entries: {
+        main: {
+          sessionId: "sess-main",
+          updatedAt: Date.now(),
+          modelProvider: "openai-codex",
+          model: "gpt-5.3-codex-spark",
+          contextTokens: 123_456,
+          totalTokens: 0,
+          totalTokensFresh: false,
+        },
+      },
+    });
+
+    const broadcastToConnIds = vi.fn();
+    const respond = vi.fn();
+    await sessionsHandlers["sessions.patch"]({
+      params: {
+        key: "main",
+        label: "Renamed",
+      },
+      respond,
+      context: {
+        broadcastToConnIds,
+        getSessionEventSubscriberConnIds: () => new Set(["conn-1"]),
+        loadGatewayModelCatalog: async () => ({ providers: [] }),
+      } as never,
+      client: null,
+      isWebchatConnect: () => false,
+    });
+
+    expect(respond).toHaveBeenCalledWith(
+      true,
+      expect.objectContaining({ ok: true, key: "agent:main:main" }),
+      undefined,
+    );
+    expect(broadcastToConnIds).toHaveBeenCalledWith(
+      "sessions.changed",
+      expect.objectContaining({
+        sessionKey: "agent:main:main",
+        reason: "patch",
+        totalTokens: 6_643,
+        totalTokensFresh: true,
+        contextTokens: 123_456,
+        estimatedCostUsd: 0,
+        modelProvider: "openai-codex",
+        model: "gpt-5.3-codex-spark",
+      }),
+      new Set(["conn-1"]),
+      { dropIfSlow: true },
+    );
+  });
+
   test("lists and patches session store via sessions.* RPC", async () => {
     const { dir, storePath } = await createSessionStoreDir();
     const now = Date.now();
diff --git a/src/gateway/session-utils.test.ts b/src/gateway/session-utils.test.ts
index 19ac3b4b425..6293119b638 100644
--- a/src/gateway/session-utils.test.ts
+++ b/src/gateway/session-utils.test.ts
@@ -877,6 +877,99 @@ describe("listSessionsFromStore search", () => {
     expect(result.sessions[0]?.estimatedCostUsd).toBeCloseTo(0.007725, 8);
   });
 
+  test("keeps zero estimated session cost when configured model pricing resolves to free", () => {
+    const cfg = {
+      session: { mainKey: "main" },
+      agents: { list: [{ id: "main", default: true }] },
+      models: {
+        providers: {
+          "openai-codex": {
+            models: [
+              {
+                id: "gpt-5.3-codex-spark",
+                label: "GPT 5.3 Codex Spark",
+                baseUrl: "https://api.openai.com/v1",
+                cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
+              },
+            ],
+          },
+        },
+      },
+    } as unknown as OpenClawConfig;
+    const result = listSessionsFromStore({
+      cfg,
+      storePath: "/tmp/sessions.json",
+      store: {
+        "agent:main:main": {
+          sessionId: "sess-main",
+          updatedAt: Date.now(),
+          modelProvider: "openai-codex",
+          model: "gpt-5.3-codex-spark",
+          inputTokens: 5_107,
+          outputTokens: 1_827,
+          cacheRead: 1_536,
+          cacheWrite: 0,
+        } as SessionEntry,
+      },
+      opts: {},
+    });
+
+    expect(result.sessions[0]?.estimatedCostUsd).toBe(0);
+  });
+
+  test("falls back to transcript usage for totalTokens and zero estimatedCostUsd", () => {
+    const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), "openclaw-session-utils-zero-cost-"));
+    const storePath = path.join(tmpDir, "sessions.json");
+    fs.writeFileSync(
+      path.join(tmpDir, "sess-main.jsonl"),
+      [
+        JSON.stringify({ type: "session", version: 1, id: "sess-main" }),
+        JSON.stringify({
+          message: {
+            role: "assistant",
+            provider: "openai-codex",
+            model: "gpt-5.3-codex-spark",
+            usage: {
+              input: 5_107,
+              output: 1_827,
+              cacheRead: 1_536,
+              cost: { total: 0 },
+            },
+          },
+        }),
+      ].join("\n"),
+      "utf-8",
+    );
+
+    try {
+      const result = listSessionsFromStore({
+        cfg: baseCfg,
+        storePath,
+        store: {
+          "agent:main:main": {
+            sessionId: "sess-main",
+            updatedAt: Date.now(),
+            modelProvider: "openai-codex",
+            model: "gpt-5.3-codex-spark",
+            totalTokens: 0,
+            totalTokensFresh: false,
+            inputTokens: 0,
+            outputTokens: 0,
+            cacheRead: 0,
+            cacheWrite: 0,
+          } as SessionEntry,
+        },
+        opts: {},
+      });
+
+      expect(result.sessions[0]?.totalTokens).toBe(6_643);
+      expect(result.sessions[0]?.totalTokensFresh).toBe(true);
+      expect(result.sessions[0]?.estimatedCostUsd).toBe(0);
+    } finally {
+      fs.rmSync(tmpDir, { recursive: true, force: true });
+    }
+  });
+
   test("falls back to transcript usage for totalTokens and estimatedCostUsd, and derives contextTokens from the resolved model", () => {
     const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), "openclaw-session-utils-"));
     const storePath = path.join(tmpDir, "sessions.json");
diff --git a/src/gateway/session-utils.ts b/src/gateway/session-utils.ts
index 039e6c77291..63c9ba0628d 100644
--- a/src/gateway/session-utils.ts
+++ b/src/gateway/session-utils.ts
@@ -226,6 +226,10 @@ function resolvePositiveNumber(value: number | null | undefined): number | undef
   return typeof value === "number" && Number.isFinite(value) && value > 0 ? value : undefined;
 }
 
+function resolveNonNegativeNumber(value: number | null | undefined): number | undefined {
+  return typeof value === "number" && Number.isFinite(value) && value >= 0 ? value : undefined;
+}
+
 function resolveEstimatedSessionCostUsd(params: {
   cfg: OpenClawConfig;
   provider?: string;
@@ -233,7 +237,7 @@ function resolveEstimatedSessionCostUsd(params: {
   entry?: Pick<SessionEntry, "inputTokens" | "outputTokens" | "cacheRead" | "cacheWrite">;
   explicitCostUsd?: number;
 }): number | undefined {
-  const explicitCostUsd = resolvePositiveNumber(params.explicitCostUsd);
+  const explicitCostUsd = resolveNonNegativeNumber(params.explicitCostUsd);
   if (explicitCostUsd !== undefined) {
     return explicitCostUsd;
   }
@@ -266,7 +270,7 @@ function resolveEstimatedSessionCostUsd(params: {
     },
     cost,
   });
-  return resolvePositiveNumber(estimated);
+  return resolveNonNegativeNumber(estimated);
 }
 
 function resolveChildSessionKeys(
@@ -1085,7 +1089,7 @@ export function buildGatewaySessionRow(params: {
       provider: modelProvider,
       model,
       entry,
-    }) ?? resolvePositiveNumber(transcriptUsage?.estimatedCostUsd);
+    }) ?? resolveNonNegativeNumber(transcriptUsage?.estimatedCostUsd);
   const contextTokens =
     resolvePositiveNumber(entry?.contextTokens) ??
     resolvePositiveNumber(transcriptUsage?.contextTokens) ??