From 32213553c1efcb656069b417b19db79c7c3f8f71 Mon Sep 17 00:00:00 2001
From: Jingyun Liu <[email protected]>
Date: Wed, 10 Jun 2026 11:54:47 -0700
Subject: [PATCH] Remove the PromptAPIForExtension flag as it has shipped for a while


Bug: 520110535
Change-Id: I98fd0ff12a715dccca18f493c4d4532e4912529c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7914988
Reviewed-by: Andrea Orru <[email protected]>
Commit-Queue: Jingyun Liu <[email protected]>
Reviewed-by: Frank Li <[email protected]>
Reviewed-by: Dave Tapuska <[email protected]>
Reviewed-by: Mike Wasserman <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1644764}
---

diff --git a/chrome/browser/extensions/ai_language_model_browsertest.cc b/chrome/browser/extensions/ai_language_model_browsertest.cc
index b28c3f43..a14fae0 100644
--- a/chrome/browser/extensions/ai_language_model_browsertest.cc
+++ b/chrome/browser/extensions/ai_language_model_browsertest.cc
@@ -46,17 +46,13 @@
 // The boolean tuple describing:
 // 1. if the `kAIPromptAPI` chrome://flag is explicitly enabled;
 // 2. if the `kAIPromptAPI` kill switch is triggered;
-// 3. if the `kAIPromptAPIForExtension` kill switch is triggered;
-using Variant = std::tuple<bool, bool, bool>;
+using Variant = std::tuple<bool, bool>;
 bool IsAPIFlagEnabled(Variant v) {
   return std::get<0>(v);
 }
 bool IsAPIKillSwitchTriggered(Variant v) {
   return std::get<1>(v);
 }
-bool IsExtensionKillSwitchTriggered(Variant v) {
-  return std::get<2>(v);
-}
 
 // Describes the test variants in a meaningful way in the parameterized tests.
 std::string DescribeTestVariant(const testing::TestParamInfo<Variant> info) {
@@ -65,11 +61,8 @@
   std::string api_kill_switch = IsAPIKillSwitchTriggered(info.param)
                                     ? "WithAPIKillswitch"
                                     : "NoAPIKillswitch";
-  std::string extension_kill_switch = IsExtensionKillSwitchTriggered(info.param)
-                                          ? "WithExtensionKillswitch"
-                                          : "NoExtensionKillswitch";
   return base::JoinString(
-      {api_flag_enabled, api_kill_switch, extension_kill_switch}, "_");
+      {api_flag_enabled, api_kill_switch}, "_");
 }
 
 }  // namespace
@@ -97,9 +90,6 @@
     if (IsAPIKillSwitchTriggered(GetParam())) {
       feature_states[blink::features::kAIPromptAPI] = false;
     }
-    if (IsExtensionKillSwitchTriggered(GetParam())) {
-      feature_states[blink::features::kAIPromptAPIForExtension] = false;
-    }
     feature_list_.InitWithFeatureStates(feature_states);
   }
 
@@ -110,7 +100,7 @@
 INSTANTIATE_TEST_SUITE_P(
     /* no prefix */,
     MAYBE_ExtensionAILanguageModelBrowserTest,
-    testing::Combine(testing::Bool(), testing::Bool(), testing::Bool()),
+    testing::Combine(testing::Bool(), testing::Bool()),
     &DescribeTestVariant);
 
 // Check whether the API is exposed to the extension worker when expected.
diff --git a/chrome/renderer/chrome_content_renderer_client.cc b/chrome/renderer/chrome_content_renderer_client.cc
index e177ede..1579f8e0 100644
--- a/chrome/renderer/chrome_content_renderer_client.cc
+++ b/chrome/renderer/chrome_content_renderer_client.cc
@@ -1450,11 +1450,6 @@
 #if !BUILDFLAG(IS_ANDROID)
     blink::WebRuntimeFeatures::EnableWebHIDOnServiceWorkers(true);
 #endif  // !BUILDFLAG(IS_ANDROID)
-    if (blink::WebRuntimeFeatures::IsAIPromptAPIForExtensionEnabled() &&
-        base::FeatureList::IsEnabled(
-            blink::features::kAIPromptAPIForExtension)) {
-      blink::WebRuntimeFeatures::EnableAIPromptAPI(true);
-    }
     blink::WebRuntimeFeatures::EnableAIPromptAPIForWorkers(true);
     blink::WebRuntimeFeatures::EnableAIPromptAPILegacyIdentifiers(true);
     blink::WebRuntimeFeatures::EnableAIPromptAPILegacyParams(true);
diff --git a/docs/experiments/prompt-api-for-extension.md b/docs/experiments/prompt-api-for-extension.md
deleted file mode 100644
index 6e54178..0000000
--- a/docs/experiments/prompt-api-for-extension.md
+++ /dev/null
@@ -1,40 +0,0 @@
-# Prompt API for extension
-
-This document describes the status of the current implementation of the
-[**Prompt API**](https://github.com/webmachinelearning/prompt-api) for Chrome
-extensions, and how to verify.
-
-## What’s supported
-
-The implementation generally intends to follow the
-[explainer](https://github.com/explainers-by-googlers/prompt-api).
-
-## Activation
-
-The API can be enabled by participating in the
-[extension origin trial](https://developer.chrome.com/blog/prompt-api-origin-trial)
-named `AIPromptAPIForExtension`. After obtaining the trial token, the
-extension authors need to configure it in the `manifest.json`:
-
-```json
-{
-  "trial_tokens": [<GENERATED_TOKEN>],
-}
-```
-
-## Verifying the API is working
-
-The extension authors can verify if the API is available by checking for the
-presence of the `LanguageModel` entrypoint from extension window and worker
-scripts. If the object is defined, the authors can follow the
-[explainer](https://github.com/explainers-by-googlers/prompt-api) and
-[developer docs](https://developer.chrome.com/docs/extensions/ai/prompt-api)
-to check availability and test the APIs usage.
-
-## Related Links
-
-- [Explainer on GitHub](https://github.com/webmachinelearning/prompt-api)
-- [API feedback](https://github.com/webmachinelearning/prompt-api/issues)
-- [Reporting bugs](https://issues.chromium.org/issues/new?component=1583624)
-- [Extension origin trial](https://developer.chrome.com/blog/prompt-api-origin-trial)
-- [Developer docs](https://developer.chrome.com/docs/extensions/ai/prompt-api)
diff --git a/third_party/blink/renderer/platform/runtime_enabled_features.json5 b/third_party/blink/renderer/platform/runtime_enabled_features.json5
index e682956..9d39720 100644
--- a/third_party/blink/renderer/platform/runtime_enabled_features.json5
+++ b/third_party/blink/renderer/platform/runtime_enabled_features.json5
@@ -410,18 +410,6 @@
       },
     },
     {
-      // Extension access to "AIPromptAPI".
-      name: "AIPromptAPIForExtension",
-      public: true,
-      status: {
-        "Win": "stable",
-        "Mac": "stable",
-        "Linux": "stable",
-        "ChromeOS": "stable",
-        "default": "",
-      },
-    },
-    {
       name: "AIPromptAPIForWorkers",
       public: true,
     },

diff --git a/chrome/browser/extensions/ai_language_model_browsertest.cc b/chrome/browser/extensions/ai_language_model_browsertest.cc
index b28c3f43..a14fae0 100644
--- a/chrome/browser/extensions/ai_language_model_browsertest.cc
+++ b/chrome/browser/extensions/ai_language_model_browsertest.cc
@@ -46,17 +46,13 @@
 // The boolean tuple describing:
 // 1. if the `kAIPromptAPI` chrome://flag is explicitly enabled;
 // 2. if the `kAIPromptAPI` kill switch is triggered;
-// 3. if the `kAIPromptAPIForExtension` kill switch is triggered;
-using Variant = std::tuple<bool, bool, bool>;
+using Variant = std::tuple<bool, bool>;
 bool IsAPIFlagEnabled(Variant v) {
   return std::get<0>(v);
 }
 bool IsAPIKillSwitchTriggered(Variant v) {
   return std::get<1>(v);
 }
-bool IsExtensionKillSwitchTriggered(Variant v) {
-  return std::get<2>(v);
-}
 
 // Describes the test variants in a meaningful way in the parameterized tests.
 std::string DescribeTestVariant(const testing::TestParamInfo<Variant> info) {
@@ -65,11 +61,8 @@
   std::string api_kill_switch = IsAPIKillSwitchTriggered(info.param)
                                     ? "WithAPIKillswitch"
                                     : "NoAPIKillswitch";
-  std::string extension_kill_switch = IsExtensionKillSwitchTriggered(info.param)
-                                          ? "WithExtensionKillswitch"
-                                          : "NoExtensionKillswitch";
   return base::JoinString(
-      {api_flag_enabled, api_kill_switch, extension_kill_switch}, "_");
+      {api_flag_enabled, api_kill_switch}, "_");
 }
 
 }  // namespace
@@ -97,9 +90,6 @@
     if (IsAPIKillSwitchTriggered(GetParam())) {
       feature_states[blink::features::kAIPromptAPI] = false;
     }
-    if (IsExtensionKillSwitchTriggered(GetParam())) {
-      feature_states[blink::features::kAIPromptAPIForExtension] = false;
-    }
     feature_list_.InitWithFeatureStates(feature_states);
   }
 
@@ -110,7 +100,7 @@
 INSTANTIATE_TEST_SUITE_P(
     /* no prefix */,
     MAYBE_ExtensionAILanguageModelBrowserTest,
-    testing::Combine(testing::Bool(), testing::Bool(), testing::Bool()),
+    testing::Combine(testing::Bool(), testing::Bool()),
     &DescribeTestVariant);
 
 // Check whether the API is exposed to the extension worker when expected.