@@ -21370,10 +21370,12 @@ paths:
         modes.
       operationId: sendChatCompletionRequest
       parameters:
-        - description: Opt-in to surface routing metadata on the response under `openrouter_metadata`. Defaults to `disabled`.
+        - description: >-
+            Opt-in to surface routing metadata on the response under `openrouter_metadata`. Defaults to `disabled`. The
+            legacy header `X-OpenRouter-Experimental-Metadata` is also accepted for backward compatibility.
           example: enabled
           in: header
-          name: X-OpenRouter-Experimental-Metadata
+          name: X-OpenRouter-Metadata
           required: false
           schema:
             $ref: '#/components/schemas/MetadataLevel'
@@ -21509,9 +21511,8 @@ paths:
                 $ref: '#/components/schemas/ForbiddenResponse'
           description: >-
             Forbidden - Authentication successful but insufficient permissions, or a guardrail blocked the request. When
-            guardrails block and the `X-OpenRouter-Experimental-Metadata: enabled` header is present, the response
-            includes `openrouter_metadata` with full routing context and a `pipeline` array containing guardrail stage
-            details.
+            guardrails block and the `X-OpenRouter-Metadata: enabled` header is present, the response includes
+            `openrouter_metadata` with full routing context and a `pipeline` array containing guardrail stage details.
         '404':
           content:
             application/json:
@@ -25228,10 +25229,12 @@ paths:
         thinking.
       operationId: createMessages
       parameters:
-        - description: Opt-in to surface routing metadata on the response under `openrouter_metadata`. Defaults to `disabled`.
+        - description: >-
+            Opt-in to surface routing metadata on the response under `openrouter_metadata`. Defaults to `disabled`. The
+            legacy header `X-OpenRouter-Experimental-Metadata` is also accepted for backward compatibility.
           example: enabled
           in: header
-          name: X-OpenRouter-Experimental-Metadata
+          name: X-OpenRouter-Metadata
           required: false
           schema:
             $ref: '#/components/schemas/MetadataLevel'
@@ -25349,9 +25352,8 @@ paths:
                 $ref: '#/components/schemas/ForbiddenResponse'
           description: >-
             Forbidden - Authentication successful but insufficient permissions, or a guardrail blocked the request. When
-            guardrails block and the `X-OpenRouter-Experimental-Metadata: enabled` header is present, the response
-            includes `openrouter_metadata` with full routing context and a `pipeline` array containing guardrail stage
-            details.
+            guardrails block and the `X-OpenRouter-Metadata: enabled` header is present, the response includes
+            `openrouter_metadata` with full routing context and a `pipeline` array containing guardrail stage details.
         '404':
           content:
             application/json:
@@ -27601,10 +27603,12 @@ paths:
       description: Creates a streaming or non-streaming response using OpenResponses API format
       operationId: createResponses
       parameters:
-        - description: Opt-in to surface routing metadata on the response under `openrouter_metadata`. Defaults to `disabled`.
+        - description: >-
+            Opt-in to surface routing metadata on the response under `openrouter_metadata`. Defaults to `disabled`. The
+            legacy header `X-OpenRouter-Experimental-Metadata` is also accepted for backward compatibility.
           example: enabled
           in: header
-          name: X-OpenRouter-Experimental-Metadata
+          name: X-OpenRouter-Metadata
           required: false
           schema:
             $ref: '#/components/schemas/MetadataLevel'
@@ -27727,9 +27731,8 @@ paths:
                 $ref: '#/components/schemas/ForbiddenResponse'
           description: >-
             Forbidden - Authentication successful but insufficient permissions, or a guardrail blocked the request. When
-            guardrails block and the `X-OpenRouter-Experimental-Metadata: enabled` header is present, the response
-            includes `openrouter_metadata` with full routing context and a `pipeline` array containing guardrail stage
-            details.
+            guardrails block and the `X-OpenRouter-Metadata: enabled` header is present, the response includes
+            `openrouter_metadata` with full routing context and a `pipeline` array containing guardrail stage details.
         '404':
           content:
             application/json: