diff --git a/baselines/dom.generated.d.ts b/baselines/dom.generated.d.ts
index 49869687a..035022af6 100644
--- a/baselines/dom.generated.d.ts
+++ b/baselines/dom.generated.d.ts
@@ -29909,7 +29909,7 @@ interface RTCRtpScriptTransform {
 
 declare var RTCRtpScriptTransform: {
     prototype: RTCRtpScriptTransform;
-    new(worker: Worker, options?: any, transfer?: any[]): RTCRtpScriptTransform;
+    new(workerOrWorkerAndParameters: Worker, options?: any, transfer?: any[]): RTCRtpScriptTransform;
 };
 
 /**
diff --git a/baselines/ts5.5/dom.generated.d.ts b/baselines/ts5.5/dom.generated.d.ts
index c2605d732..ab19d96d4 100644
--- a/baselines/ts5.5/dom.generated.d.ts
+++ b/baselines/ts5.5/dom.generated.d.ts
@@ -29885,7 +29885,7 @@ interface RTCRtpScriptTransform {
 
 declare var RTCRtpScriptTransform: {
     prototype: RTCRtpScriptTransform;
-    new(worker: Worker, options?: any, transfer?: any[]): RTCRtpScriptTransform;
+    new(workerOrWorkerAndParameters: Worker, options?: any, transfer?: any[]): RTCRtpScriptTransform;
 };
 
 /**
diff --git a/baselines/ts5.6/dom.generated.d.ts b/baselines/ts5.6/dom.generated.d.ts
index 080755c34..03a868e42 100644
--- a/baselines/ts5.6/dom.generated.d.ts
+++ b/baselines/ts5.6/dom.generated.d.ts
@@ -29906,7 +29906,7 @@ interface RTCRtpScriptTransform {
 
 declare var RTCRtpScriptTransform: {
     prototype: RTCRtpScriptTransform;
-    new(worker: Worker, options?: any, transfer?: any[]): RTCRtpScriptTransform;
+    new(workerOrWorkerAndParameters: Worker, options?: any, transfer?: any[]): RTCRtpScriptTransform;
 };
 
 /**
diff --git a/baselines/ts5.9/dom.generated.d.ts b/baselines/ts5.9/dom.generated.d.ts
index e7d397376..67f588264 100644
--- a/baselines/ts5.9/dom.generated.d.ts
+++ b/baselines/ts5.9/dom.generated.d.ts
@@ -29906,7 +29906,7 @@ interface RTCRtpScriptTransform {
 
 declare var RTCRtpScriptTransform: {
     prototype: RTCRtpScriptTransform;
-    new(worker: Worker, options?: any, transfer?: any[]): RTCRtpScriptTransform;
+    new(workerOrWorkerAndParameters: Worker, options?: any, transfer?: any[]): RTCRtpScriptTransform;
 };
 
 /**
diff --git a/inputfiles/patches/webrtc-encoded-transform.kdl b/inputfiles/patches/webrtc-encoded-transform.kdl
index 6c3bc9746..5d3c2548d 100644
--- a/inputfiles/patches/webrtc-encoded-transform.kdl
+++ b/inputfiles/patches/webrtc-encoded-transform.kdl
@@ -10,6 +10,15 @@ interface RTCEncodedVideoFrame {
   property timestamp type="long long" readonly=#true mdnUrl="https://developer.mozilla.org/docs/Web/API/RTCEncodedVideoFrame/timestamp"
 }
 
+interface RTCRtpScriptTransform {
+  constructor signatureIndex=0 {
+    // WorkerOrWorkerAndParameters has no implementation as of 2026-04
+    param workerOrWorkerAndParameters name="worker" {
+      type Worker
+    }
+  }
+}
+
 removals {
   dictionary RTCEncodedAudioFrameMetadata {
     member audioLevel // No implementation as of 2025-05
diff --git a/package-lock.json b/package-lock.json
index 6484c8808..b0796199b 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1098,9 +1098,9 @@
       "license": "MIT"
     },
     "node_modules/@webref/idl": {
-      "version": "3.75.0",
-      "resolved": "https://registry.npmjs.org/@webref/idl/-/idl-3.75.0.tgz",
-      "integrity": "sha512-elNqHSpNHTzaS368irlla8Dbp7neH7FhV0Cz3E9d/7GKTELdvGobA3i6tsg91w1CGy80kBmBpOCJM/3Z8KZUhw==",
+      "version": "3.75.1",
+      "resolved": "https://registry.npmjs.org/@webref/idl/-/idl-3.75.1.tgz",
+      "integrity": "sha512-Wgd7hBxY6+Ji/JrYrvMevxWXEw0UDoZSDyZDNs2kneDW7LjTiih4cMK0UR+LmB1JfMs5dsqN137TfKVGv3RMRA==",
       "dev": true,
       "license": "MIT",
       "peerDependencies": {
diff --git a/src/build/patches.ts b/src/build/patches.ts
index 86a5df165..86a4a3af6 100644
--- a/src/build/patches.ts
+++ b/src/build/patches.ts
@@ -222,7 +222,7 @@ function handleMixinAndInterfaces(
   node: Node,
   type: "mixin" | "interface",
 ): DeepPartial<Interface> {
-  const name = string(node.properties?.name || node.values[0]);
+  const name = string(node.properties.name || node.values[0]);
 
   const event: Event[] = [];
   const property: Record<string, DeepPartial<Property>> = {};