diff --git a/api/CreateMonitor.json b/api/CreateMonitor.json
new file mode 100644
index 00000000000000..3f496c8842a11d
--- /dev/null
+++ b/api/CreateMonitor.json
@@ -0,0 +1,85 @@
+{
+  "api": {
+    "CreateMonitor": {
+      "__compat": {
+        "spec_url": "https://webmachinelearning.github.io/writing-assistance-apis/#createmonitor",
+        "support": {
+          "chrome": {
+            "version_added": "138"
+          },
+          "chrome_android": "mirror",
+          "deno": {
+            "version_added": false
+          },
+          "edge": "mirror",
+          "firefox": {
+            "version_added": false
+          },
+          "firefox_android": "mirror",
+          "ie": {
+            "version_added": false
+          },
+          "nodejs": {
+            "version_added": false
+          },
+          "oculus": "mirror",
+          "opera": "mirror",
+          "opera_android": "mirror",
+          "safari": {
+            "version_added": false
+          },
+          "safari_ios": "mirror",
+          "samsunginternet_android": "mirror",
+          "webview_android": "mirror",
+          "webview_ios": "mirror"
+        },
+        "status": {
+          "experimental": true,
+          "standard_track": true,
+          "deprecated": false
+        }
+      },
+      "downloadprogress_event": {
+        "__compat": {
+          "description": "`downloadprogress` event",
+          "spec_url": "https://webmachinelearning.github.io/writing-assistance-apis/#dom-createmonitor-ondownloadprogress",
+          "support": {
+            "chrome": {
+              "version_added": "138"
+            },
+            "chrome_android": "mirror",
+            "deno": {
+              "version_added": false
+            },
+            "edge": "mirror",
+            "firefox": {
+              "version_added": false
+            },
+            "firefox_android": "mirror",
+            "ie": {
+              "version_added": false
+            },
+            "nodejs": {
+              "version_added": false
+            },
+            "oculus": "mirror",
+            "opera": "mirror",
+            "opera_android": "mirror",
+            "safari": {
+              "version_added": false
+            },
+            "safari_ios": "mirror",
+            "samsunginternet_android": "mirror",
+            "webview_android": "mirror",
+            "webview_ios": "mirror"
+          },
+          "status": {
+            "experimental": true,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      }
+    }
+  }
+}
diff --git a/api/Summarizer.json b/api/Summarizer.json
new file mode 100644
index 00000000000000..da46e6654a3e67
--- /dev/null
+++ b/api/Summarizer.json
@@ -0,0 +1,618 @@
+{
+  "api": {
+    "Summarizer": {
+      "__compat": {
+        "spec_url": "https://webmachinelearning.github.io/writing-assistance-apis/#summarizer",
+        "support": {
+          "chrome": {
+            "version_added": "138"
+          },
+          "chrome_android": "mirror",
+          "deno": {
+            "version_added": false
+          },
+          "edge": "mirror",
+          "firefox": {
+            "version_added": false
+          },
+          "firefox_android": "mirror",
+          "ie": {
+            "version_added": false
+          },
+          "nodejs": {
+            "version_added": false
+          },
+          "oculus": "mirror",
+          "opera": "mirror",
+          "opera_android": "mirror",
+          "safari": {
+            "version_added": false
+          },
+          "safari_ios": "mirror",
+          "samsunginternet_android": "mirror",
+          "webview_android": "mirror",
+          "webview_ios": "mirror"
+        },
+        "status": {
+          "experimental": true,
+          "standard_track": true,
+          "deprecated": false
+        }
+      },
+      "availability_static": {
+        "__compat": {
+          "description": "`availability()` static method",
+          "spec_url": "https://webmachinelearning.github.io/writing-assistance-apis/#dom-summarizer-availability",
+          "support": {
+            "chrome": {
+              "version_added": "138"
+            },
+            "chrome_android": "mirror",
+            "deno": {
+              "version_added": false
+            },
+            "edge": "mirror",
+            "firefox": {
+              "version_added": false
+            },
+            "firefox_android": "mirror",
+            "ie": {
+              "version_added": false
+            },
+            "nodejs": {
+              "version_added": false
+            },
+            "oculus": "mirror",
+            "opera": "mirror",
+            "opera_android": "mirror",
+            "safari": {
+              "version_added": false
+            },
+            "safari_ios": "mirror",
+            "samsunginternet_android": "mirror",
+            "webview_android": "mirror",
+            "webview_ios": "mirror"
+          },
+          "status": {
+            "experimental": true,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      },
+      "create_static": {
+        "__compat": {
+          "description": "`create()` static method",
+          "spec_url": "https://webmachinelearning.github.io/writing-assistance-apis/#dom-summarizer-create",
+          "support": {
+            "chrome": {
+              "version_added": "138"
+            },
+            "chrome_android": "mirror",
+            "deno": {
+              "version_added": false
+            },
+            "edge": "mirror",
+            "firefox": {
+              "version_added": false
+            },
+            "firefox_android": "mirror",
+            "ie": {
+              "version_added": false
+            },
+            "nodejs": {
+              "version_added": false
+            },
+            "oculus": "mirror",
+            "opera": "mirror",
+            "opera_android": "mirror",
+            "safari": {
+              "version_added": false
+            },
+            "safari_ios": "mirror",
+            "samsunginternet_android": "mirror",
+            "webview_android": "mirror",
+            "webview_ios": "mirror"
+          },
+          "status": {
+            "experimental": true,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      },
+      "destroy": {
+        "__compat": {
+          "description": "`destroy()` instance method",
+          "spec_url": "https://webmachinelearning.github.io/writing-assistance-apis/#dom-destroyablemodel-destroy",
+          "support": {
+            "chrome": {
+              "version_added": "138"
+            },
+            "chrome_android": "mirror",
+            "deno": {
+              "version_added": false
+            },
+            "edge": "mirror",
+            "firefox": {
+              "version_added": false
+            },
+            "firefox_android": "mirror",
+            "ie": {
+              "version_added": false
+            },
+            "nodejs": {
+              "version_added": false
+            },
+            "oculus": "mirror",
+            "opera": "mirror",
+            "opera_android": "mirror",
+            "safari": {
+              "version_added": false
+            },
+            "safari_ios": "mirror",
+            "samsunginternet_android": "mirror",
+            "webview_android": "mirror",
+            "webview_ios": "mirror"
+          },
+          "status": {
+            "experimental": true,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      },
+      "expectedContextLanguages": {
+        "__compat": {
+          "description": "`expectedContextLanguages` property",
+          "spec_url": "https://webmachinelearning.github.io/writing-assistance-apis/#dom-summarizer-expectedcontextlanguages",
+          "support": {
+            "chrome": {
+              "version_added": "138"
+            },
+            "chrome_android": "mirror",
+            "deno": {
+              "version_added": false
+            },
+            "edge": "mirror",
+            "firefox": {
+              "version_added": false
+            },
+            "firefox_android": "mirror",
+            "ie": {
+              "version_added": false
+            },
+            "nodejs": {
+              "version_added": false
+            },
+            "oculus": "mirror",
+            "opera": "mirror",
+            "opera_android": "mirror",
+            "safari": {
+              "version_added": false
+            },
+            "safari_ios": "mirror",
+            "samsunginternet_android": "mirror",
+            "webview_android": "mirror",
+            "webview_ios": "mirror"
+          },
+          "status": {
+            "experimental": true,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      },
+      "expectedInputLanguages": {
+        "__compat": {
+          "description": "`expectedInputLanguages` property",
+          "spec_url": "https://webmachinelearning.github.io/writing-assistance-apis/#dom-summarizer-expectedinputlanguages",
+          "support": {
+            "chrome": {
+              "version_added": "138"
+            },
+            "chrome_android": "mirror",
+            "deno": {
+              "version_added": false
+            },
+            "edge": "mirror",
+            "firefox": {
+              "version_added": false
+            },
+            "firefox_android": "mirror",
+            "ie": {
+              "version_added": false
+            },
+            "nodejs": {
+              "version_added": false
+            },
+            "oculus": "mirror",
+            "opera": "mirror",
+            "opera_android": "mirror",
+            "safari": {
+              "version_added": false
+            },
+            "safari_ios": "mirror",
+            "samsunginternet_android": "mirror",
+            "webview_android": "mirror",
+            "webview_ios": "mirror"
+          },
+          "status": {
+            "experimental": true,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      },
+      "format": {
+        "__compat": {
+          "description": "`format` property",
+          "spec_url": "https://webmachinelearning.github.io/writing-assistance-apis/#dom-summarizer-format",
+          "support": {
+            "chrome": {
+              "version_added": "138"
+            },
+            "chrome_android": "mirror",
+            "deno": {
+              "version_added": false
+            },
+            "edge": "mirror",
+            "firefox": {
+              "version_added": false
+            },
+            "firefox_android": "mirror",
+            "ie": {
+              "version_added": false
+            },
+            "nodejs": {
+              "version_added": false
+            },
+            "oculus": "mirror",
+            "opera": "mirror",
+            "opera_android": "mirror",
+            "safari": {
+              "version_added": false
+            },
+            "safari_ios": "mirror",
+            "samsunginternet_android": "mirror",
+            "webview_android": "mirror",
+            "webview_ios": "mirror"
+          },
+          "status": {
+            "experimental": true,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      },
+      "inputQuota": {
+        "__compat": {
+          "description": "`inputQuota` property",
+          "spec_url": "https://webmachinelearning.github.io/writing-assistance-apis/#dom-summarizer-inputquota",
+          "support": {
+            "chrome": {
+              "version_added": "138"
+            },
+            "chrome_android": "mirror",
+            "deno": {
+              "version_added": false
+            },
+            "edge": "mirror",
+            "firefox": {
+              "version_added": false
+            },
+            "firefox_android": "mirror",
+            "ie": {
+              "version_added": false
+            },
+            "nodejs": {
+              "version_added": false
+            },
+            "oculus": "mirror",
+            "opera": "mirror",
+            "opera_android": "mirror",
+            "safari": {
+              "version_added": false
+            },
+            "safari_ios": "mirror",
+            "samsunginternet_android": "mirror",
+            "webview_android": "mirror",
+            "webview_ios": "mirror"
+          },
+          "status": {
+            "experimental": true,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      },
+      "length": {
+        "__compat": {
+          "description": "`length` property",
+          "spec_url": "https://webmachinelearning.github.io/writing-assistance-apis/#dom-summarizer-length",
+          "support": {
+            "chrome": {
+              "version_added": "138"
+            },
+            "chrome_android": "mirror",
+            "deno": {
+              "version_added": false
+            },
+            "edge": "mirror",
+            "firefox": {
+              "version_added": false
+            },
+            "firefox_android": "mirror",
+            "ie": {
+              "version_added": false
+            },
+            "nodejs": {
+              "version_added": false
+            },
+            "oculus": "mirror",
+            "opera": "mirror",
+            "opera_android": "mirror",
+            "safari": {
+              "version_added": false
+            },
+            "safari_ios": "mirror",
+            "samsunginternet_android": "mirror",
+            "webview_android": "mirror",
+            "webview_ios": "mirror"
+          },
+          "status": {
+            "experimental": true,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      },
+      "measureInputUsage": {
+        "__compat": {
+          "description": "`measureInputUsage()` instance method",
+          "spec_url": "https://webmachinelearning.github.io/writing-assistance-apis/#dom-summarizer-measureinputusage",
+          "support": {
+            "chrome": {
+              "version_added": "138"
+            },
+            "chrome_android": "mirror",
+            "deno": {
+              "version_added": false
+            },
+            "edge": "mirror",
+            "firefox": {
+              "version_added": false
+            },
+            "firefox_android": "mirror",
+            "ie": {
+              "version_added": false
+            },
+            "nodejs": {
+              "version_added": false
+            },
+            "oculus": "mirror",
+            "opera": "mirror",
+            "opera_android": "mirror",
+            "safari": {
+              "version_added": false
+            },
+            "safari_ios": "mirror",
+            "samsunginternet_android": "mirror",
+            "webview_android": "mirror",
+            "webview_ios": "mirror"
+          },
+          "status": {
+            "experimental": true,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      },
+      "outputLanguage": {
+        "__compat": {
+          "description": "`outputLanguage` property",
+          "spec_url": "https://webmachinelearning.github.io/writing-assistance-apis/#dom-summarizer-outputlanguage",
+          "support": {
+            "chrome": {
+              "version_added": "138"
+            },
+            "chrome_android": "mirror",
+            "deno": {
+              "version_added": false
+            },
+            "edge": "mirror",
+            "firefox": {
+              "version_added": false
+            },
+            "firefox_android": "mirror",
+            "ie": {
+              "version_added": false
+            },
+            "nodejs": {
+              "version_added": false
+            },
+            "oculus": "mirror",
+            "opera": "mirror",
+            "opera_android": "mirror",
+            "safari": {
+              "version_added": false
+            },
+            "safari_ios": "mirror",
+            "samsunginternet_android": "mirror",
+            "webview_android": "mirror",
+            "webview_ios": "mirror"
+          },
+          "status": {
+            "experimental": true,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      },
+      "sharedContext": {
+        "__compat": {
+          "description": "`sharedContext` property",
+          "spec_url": "https://webmachinelearning.github.io/writing-assistance-apis/#dom-summarizer-sharedcontext",
+          "support": {
+            "chrome": {
+              "version_added": "138"
+            },
+            "chrome_android": "mirror",
+            "deno": {
+              "version_added": false
+            },
+            "edge": "mirror",
+            "firefox": {
+              "version_added": false
+            },
+            "firefox_android": "mirror",
+            "ie": {
+              "version_added": false
+            },
+            "nodejs": {
+              "version_added": false
+            },
+            "oculus": "mirror",
+            "opera": "mirror",
+            "opera_android": "mirror",
+            "safari": {
+              "version_added": false
+            },
+            "safari_ios": "mirror",
+            "samsunginternet_android": "mirror",
+            "webview_android": "mirror",
+            "webview_ios": "mirror"
+          },
+          "status": {
+            "experimental": true,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      },
+      "summarize": {
+        "__compat": {
+          "description": "`summarize()` instance method",
+          "spec_url": "https://webmachinelearning.github.io/writing-assistance-apis/#dom-summarizer-summarize",
+          "support": {
+            "chrome": {
+              "version_added": "138"
+            },
+            "chrome_android": "mirror",
+            "deno": {
+              "version_added": false
+            },
+            "edge": "mirror",
+            "firefox": {
+              "version_added": false
+            },
+            "firefox_android": "mirror",
+            "ie": {
+              "version_added": false
+            },
+            "nodejs": {
+              "version_added": false
+            },
+            "oculus": "mirror",
+            "opera": "mirror",
+            "opera_android": "mirror",
+            "safari": {
+              "version_added": false
+            },
+            "safari_ios": "mirror",
+            "samsunginternet_android": "mirror",
+            "webview_android": "mirror",
+            "webview_ios": "mirror"
+          },
+          "status": {
+            "experimental": true,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      },
+      "summarizeStreaming": {
+        "__compat": {
+          "description": "`summarizeStreaming()` instance method",
+          "spec_url": "https://webmachinelearning.github.io/writing-assistance-apis/#dom-summarizer-summarizestreaming",
+          "support": {
+            "chrome": {
+              "version_added": "138"
+            },
+            "chrome_android": "mirror",
+            "deno": {
+              "version_added": false
+            },
+            "edge": "mirror",
+            "firefox": {
+              "version_added": false
+            },
+            "firefox_android": "mirror",
+            "ie": {
+              "version_added": false
+            },
+            "nodejs": {
+              "version_added": false
+            },
+            "oculus": "mirror",
+            "opera": "mirror",
+            "opera_android": "mirror",
+            "safari": {
+              "version_added": false
+            },
+            "safari_ios": "mirror",
+            "samsunginternet_android": "mirror",
+            "webview_android": "mirror",
+            "webview_ios": "mirror"
+          },
+          "status": {
+            "experimental": true,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      },
+      "type": {
+        "__compat": {
+          "description": "`type` property",
+          "spec_url": "https://webmachinelearning.github.io/writing-assistance-apis/#dom-summarizer-type",
+          "support": {
+            "chrome": {
+              "version_added": "138"
+            },
+            "chrome_android": "mirror",
+            "deno": {
+              "version_added": false
+            },
+            "edge": "mirror",
+            "firefox": {
+              "version_added": false
+            },
+            "firefox_android": "mirror",
+            "ie": {
+              "version_added": false
+            },
+            "nodejs": {
+              "version_added": false
+            },
+            "oculus": "mirror",
+            "opera": "mirror",
+            "opera_android": "mirror",
+            "safari": {
+              "version_added": false
+            },
+            "safari_ios": "mirror",
+            "samsunginternet_android": "mirror",
+            "webview_android": "mirror",
+            "webview_ios": "mirror"
+          },
+          "status": {
+            "experimental": true,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      }
+    }
+  }
+}
diff --git a/http/headers/Permissions-Policy.json b/http/headers/Permissions-Policy.json
index 4a433508dbeb8c..0103c328c2cd95 100644
--- a/http/headers/Permissions-Policy.json
+++ b/http/headers/Permissions-Policy.json
@@ -1310,6 +1310,40 @@
             }
           }
         },
+        "summarizer": {
+          "__compat": {
+            "spec_url": "https://webmachinelearning.github.io/writing-assistance-apis/#summarizer-permissions-policy",
+            "support": {
+              "chrome": {
+                "version_added": "138"
+              },
+              "chrome_android": "mirror",
+              "edge": "mirror",
+              "firefox": {
+                "version_added": false
+              },
+              "firefox_android": "mirror",
+              "ie": {
+                "version_added": false
+              },
+              "oculus": "mirror",
+              "opera": "mirror",
+              "opera_android": "mirror",
+              "safari": {
+                "version_added": false
+              },
+              "safari_ios": "mirror",
+              "samsunginternet_android": "mirror",
+              "webview_android": "mirror",
+              "webview_ios": "mirror"
+            },
+            "status": {
+              "experimental": true,
+              "standard_track": true,
+              "deprecated": false
+            }
+          }
+        },
         "usb": {
           "__compat": {
             "mdn_url": "https://developer.mozilla.org/docs/Web/HTTP/Reference/Headers/Permissions-Policy/usb",