diff --git a/src/web-server/usage/routes.ts b/src/web-server/usage/routes.ts
index c4a2dabe..2aeec59f 100644
--- a/src/web-server/usage/routes.ts
+++ b/src/web-server/usage/routes.ts
@@ -8,6 +8,7 @@
  */
 
 import { Router } from 'express';
+import { requireLocalAccessWhenAuthDisabled } from '../middleware/auth-middleware';
 import {
   handleSummary,
   handleDaily,
@@ -24,6 +25,20 @@ export { prewarmUsageCache, clearUsageCache, getLastFetchTimestamp } from './agg
 
 export const usageRoutes = Router();
 
+const USAGE_WRITE_ACCESS_ERROR =
+  'Usage refresh requires localhost access when dashboard auth is disabled.';
+
+usageRoutes.use((req, res, next) => {
+  if (req.method.toUpperCase() !== 'POST') {
+    next();
+    return;
+  }
+
+  if (requireLocalAccessWhenAuthDisabled(req, res, USAGE_WRITE_ACCESS_ERROR)) {
+    next();
+  }
+});
+
 // Summary endpoint
 usageRoutes.get('/summary', handleSummary);
 
diff --git a/tests/unit/web-server/usage-routes-auth.test.ts b/tests/unit/web-server/usage-routes-auth.test.ts
new file mode 100644
index 00000000..424263ff
--- /dev/null
+++ b/tests/unit/web-server/usage-routes-auth.test.ts
@@ -0,0 +1,92 @@
+import { afterAll, afterEach, beforeAll, beforeEach, describe, expect, it } from 'bun:test';
+import express from 'express';
+import * as fs from 'fs';
+import * as os from 'os';
+import * as path from 'path';
+import type { Server } from 'http';
+import { usageRoutes } from '../../../src/web-server/usage/routes';
+
+describe('usage-routes remote write guard', () => {
+  let server: Server;
+  let baseUrl = '';
+  let forcedRemoteAddress = '127.0.0.1';
+  let tempHome = '';
+  let originalDashboardAuthEnabled: string | undefined;
+  let originalCcsHome: string | undefined;
+
+  beforeAll(async () => {
+    const app = express();
+    app.use(express.json());
+    app.use((req, _res, next) => {
+      Object.defineProperty(req.socket, 'remoteAddress', {
+        value: forcedRemoteAddress,
+        configurable: true,
+      });
+      next();
+    });
+    app.use('/api/usage', usageRoutes);
+
+    await new Promise<void>((resolve, reject) => {
+      server = app.listen(0, '127.0.0.1');
+      server.once('error', reject);
+      server.once('listening', () => resolve());
+    });
+
+    const address = server.address();
+    if (!address || typeof address === 'string') {
+      throw new Error('Unable to resolve test server port');
+    }
+    baseUrl = `http://127.0.0.1:${address.port}`;
+  });
+
+  afterAll(async () => {
+    await new Promise<void>((resolve) => server.close(() => resolve()));
+  });
+
+  beforeEach(() => {
+    originalDashboardAuthEnabled = process.env.CCS_DASHBOARD_AUTH_ENABLED;
+    originalCcsHome = process.env.CCS_HOME;
+    tempHome = fs.mkdtempSync(path.join(os.tmpdir(), 'ccs-usage-routes-auth-'));
+    process.env.CCS_HOME = tempHome;
+    process.env.CCS_DASHBOARD_AUTH_ENABLED = 'false';
+    forcedRemoteAddress = '10.10.0.24';
+  });
+
+  afterEach(() => {
+    if (originalDashboardAuthEnabled !== undefined) {
+      process.env.CCS_DASHBOARD_AUTH_ENABLED = originalDashboardAuthEnabled;
+    } else {
+      delete process.env.CCS_DASHBOARD_AUTH_ENABLED;
+    }
+
+    if (originalCcsHome !== undefined) {
+      process.env.CCS_HOME = originalCcsHome;
+    } else {
+      delete process.env.CCS_HOME;
+    }
+
+    if (tempHome && fs.existsSync(tempHome)) {
+      fs.rmSync(tempHome, { recursive: true, force: true });
+      tempHome = '';
+    }
+  });
+
+  it('allows remote read-only usage status requests when dashboard auth is disabled', async () => {
+    const response = await fetch(`${baseUrl}/api/usage/status`);
+
+    expect(response.status).toBe(200);
+  });
+
+  it('blocks remote usage refresh when dashboard auth is disabled', async () => {
+    const response = await fetch(`${baseUrl}/api/usage/refresh`, {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({}),
+    });
+
+    expect(response.status).toBe(403);
+    expect(await response.json()).toEqual({
+      error: 'Usage refresh requires localhost access when dashboard auth is disabled.',
+    });
+  });
+});