diff --git a/src/utils/apiPreconnect.test.ts b/src/utils/apiPreconnect.test.ts
new file mode 100644
index 00000000..1cce48c6
--- /dev/null
+++ b/src/utils/apiPreconnect.test.ts
@@ -0,0 +1,69 @@
+import { afterEach, beforeEach, describe, expect, mock, test } from 'bun:test'
+
+const originalEnv = { ...process.env }
+const originalFetch = globalThis.fetch
+
+async function importFreshModule() {
+  return import(`./apiPreconnect.ts?ts=${Date.now()}-${Math.random()}`)
+}
+
+beforeEach(() => {
+  process.env = { ...originalEnv }
+})
+
+afterEach(() => {
+  process.env = { ...originalEnv }
+  globalThis.fetch = originalFetch
+})
+
+describe('preconnectAnthropicApi', () => {
+  test('does not fetch when OpenAI mode is enabled', async () => {
+    process.env.CLAUDE_CODE_USE_OPENAI = '1'
+    const fetchMock = mock(() => Promise.resolve(new Response(null, { status: 200 })))
+    globalThis.fetch = fetchMock as typeof globalThis.fetch
+
+    const { preconnectAnthropicApi } = await importFreshModule()
+    preconnectAnthropicApi()
+
+    expect(fetchMock).not.toHaveBeenCalled()
+  })
+
+  test('does not fetch when Gemini mode is enabled', async () => {
+    process.env.CLAUDE_CODE_USE_GEMINI = '1'
+    const fetchMock = mock(() => Promise.resolve(new Response(null, { status: 200 })))
+    globalThis.fetch = fetchMock as typeof globalThis.fetch
+
+    const { preconnectAnthropicApi } = await importFreshModule()
+    preconnectAnthropicApi()
+
+    expect(fetchMock).not.toHaveBeenCalled()
+  })
+
+  test('does not fetch when GitHub mode is enabled', async () => {
+    process.env.CLAUDE_CODE_USE_GITHUB = '1'
+    const fetchMock = mock(() => Promise.resolve(new Response(null, { status: 200 })))
+    globalThis.fetch = fetchMock as typeof globalThis.fetch
+
+    const { preconnectAnthropicApi } = await importFreshModule()
+    preconnectAnthropicApi()
+
+    expect(fetchMock).not.toHaveBeenCalled()
+  })
+
+  test('fetches in first-party mode', async () => {
+    delete process.env.CLAUDE_CODE_USE_OPENAI
+    delete process.env.CLAUDE_CODE_USE_GEMINI
+    delete process.env.CLAUDE_CODE_USE_GITHUB
+    delete process.env.CLAUDE_CODE_USE_BEDROCK
+    delete process.env.CLAUDE_CODE_USE_VERTEX
+    delete process.env.CLAUDE_CODE_USE_FOUNDRY
+
+    const fetchMock = mock(() => Promise.resolve(new Response(null, { status: 200 })))
+    globalThis.fetch = fetchMock as typeof globalThis.fetch
+
+    const { preconnectAnthropicApi } = await importFreshModule()
+    preconnectAnthropicApi()
+
+    expect(fetchMock).toHaveBeenCalledTimes(1)
+  })
+})
diff --git a/src/utils/apiPreconnect.ts b/src/utils/apiPreconnect.ts
index 6a8de649..103198da 100644
--- a/src/utils/apiPreconnect.ts
+++ b/src/utils/apiPreconnect.ts
@@ -25,6 +25,7 @@
 
 import { getOauthConfig } from '../constants/oauth.js'
 import { isEnvTruthy } from './envUtils.js'
+import { getAPIProvider } from './model/providers.js'
 
 let fired = false
 
@@ -32,6 +33,11 @@ export function preconnectAnthropicApi(): void {
   if (fired) return
   fired = true
 
+  // Third-party providers should not warm a connection to Anthropic.
+  if (getAPIProvider() !== 'firstParty') {
+    return
+  }
+
   // Skip if using a cloud provider — different endpoint + auth
   if (
     isEnvTruthy(process.env.CLAUDE_CODE_USE_BEDROCK) ||