diff --git a/apis/validator/block.v4.yaml b/apis/validator/block.v4.yaml
index f53f4241..ef7290d2 100644
--- a/apis/validator/block.v4.yaml
+++ b/apis/validator/block.v4.yaml
@@ -11,6 +11,14 @@ get:
     so there is no longer a concept of blinded or unblinded blocks. Builders release the
     payload later. This endpoint is specific to the post-Gloas forks and is not backwards compatible
     with previous forks.
+
+    When self-building (local execution payload), the response will include the full block contents
+    including the beacon block, execution payload envelope, blobs, and KZG proofs.
+    When using an external builder bid, only the `BeaconBlock` is returned as the beacon node
+    does not have access to the builder's execution payload.
+
+    The `Eth-Execution-Payload-Included` header and `execution_payload_included` response field
+    indicate which response type was returned.
   parameters:
     - name: slot
       in: path
@@ -32,6 +40,29 @@ get:
         $ref: '../../beacon-node-oapi.yaml#/components/schemas/Graffiti'
     - name: skip_randao_verification
       $ref: '../../beacon-node-oapi.yaml#/components/parameters/SkipRandaoVerification'
+    - name: include_payload
+      in: query
+      required: false
+      description: |
+        Controls whether the execution payload envelope and blobs are included in the response
+        when self-building (using local execution payload).
+
+        When `true` (default), the response includes the full block contents: beacon block,
+        execution payload envelope, blobs, and KZG proofs. This enables stateless operation
+        where the validator client can use multiple beacon nodes (multi-BN setups, DVs, failover).
+
+        When `false`, only the beacon block is returned and the beacon node caches the execution
+        payload envelope and blobs internally. The validator client must then fetch them separately
+        via `GET /eth/v1/validator/execution_payload_envelope/{slot}/{builder_index}`. This saves
+        bandwidth but requires the validator client to publish via the same beacon node that
+        produced the block (stateful operation).
+
+        This parameter only affects self-building scenarios. When using an external builder's bid,
+        only the beacon block is returned regardless of this parameter (the beacon node does not
+        have access to the builder's execution payload).
+      schema:
+        type: boolean
+        default: true
     - name: builder_boost_factor
       in: query
       required: false
@@ -72,12 +103,14 @@ get:
           $ref: '../../beacon-node-oapi.yaml#/components/headers/Eth-Consensus-Version'
         Eth-Consensus-Block-Value:
           $ref: '../../beacon-node-oapi.yaml#/components/headers/Eth-Consensus-Block-Value'
+        Eth-Execution-Payload-Included:
+          $ref: '../../beacon-node-oapi.yaml#/components/headers/Eth-Execution-Payload-Included'
       content:
         application/json:
           schema:
             title: "ProduceBlockV4Response"
             type: object
-            required: [version, consensus_block_value, data]
+            required: [version, consensus_block_value, execution_payload_included, data]
             properties:
               version:
                 type: string
@@ -87,11 +120,21 @@ get:
                 type: string
                 example: "12345"
                 description: "Consensus rewards for this block in Wei"
+              execution_payload_included:
+                type: boolean
+                description: |
+                  Indicates whether the execution payload envelope is included in the response.
+                  When `true`, the `data` field contains the full
+                  execution payload envelope, blobs, and KZG proofs. When `false`, the `data`
+                  field contains only a `BeaconBlock`.
+                example: false
               data:
-                $ref: "../../beacon-node-oapi.yaml#/components/schemas/Gloas.BeaconBlock"
+                anyOf:
+                  - $ref: "../../beacon-node-oapi.yaml#/components/schemas/Gloas.BeaconBlock"
+                  - $ref: "../../beacon-node-oapi.yaml#/components/schemas/Gloas.BlockContents"
         application/octet-stream:
           schema:
-            description: "SSZ serialized `BeaconBlock` bytes. Use Accept header to choose this response type, version string is sent in header `Eth-Consensus-Version`."
+            description: "SSZ serialized `BeaconBlock` or `BlockContents` bytes. Use Accept header to choose this response type, version string is sent in header `Eth-Consensus-Version` and payload inclusion indicated by `Eth-Execution-Payload-Included` header."
     "400":
       description: "Invalid block production request"
       content:
diff --git a/beacon-node-oapi.yaml b/beacon-node-oapi.yaml
index dc612d42..aa3b3b0a 100644
--- a/beacon-node-oapi.yaml
+++ b/beacon-node-oapi.yaml
@@ -451,6 +451,8 @@ components:
       $ref: "./types/gloas/block.yaml#/Gloas/BeaconBlock"
     Gloas.SignedBeaconBlock:
       $ref: "./types/gloas/block.yaml#/Gloas/SignedBeaconBlock"
+    Gloas.BlockContents:
+      $ref: "./types/gloas/block_contents.yaml#/Gloas/BlockContents"
     Gloas.ExecutionPayloadBid:
       $ref: "./types/gloas/execution_payload_bid.yaml#/Gloas/ExecutionPayloadBid"
     Gloas.SignedExecutionPayloadBid:
@@ -538,3 +540,9 @@ components:
       required: true
       schema:
         $ref: './types/primitive.yaml#/Wei'
+    Eth-Execution-Payload-Included:
+      description: |
+        Indicates whether the execution payload envelope, blobs, and KZG proofs are included in the response. Required in response so client can deserialize returned data.
+      required: true
+      schema:
+        type: boolean
diff --git a/types/gloas/block_contents.yaml b/types/gloas/block_contents.yaml
new file mode 100644
index 00000000..84206540
--- /dev/null
+++ b/types/gloas/block_contents.yaml
@@ -0,0 +1,17 @@
+Gloas:
+  BlockContents:
+    type: object
+    description: |
+      Block contents for self-building, including the execution payload envelope
+      and blobs. This enables stateless failover to another beacon node for publishing,
+      as all required data is returned in a single response.
+    required: [block, execution_payload_envelope, kzg_proofs, blobs]
+    properties:
+      block:
+        $ref: "./block.yaml#/Gloas/BeaconBlock"
+      execution_payload_envelope:
+        $ref: "./execution_payload_envelope.yaml#/Gloas/ExecutionPayloadEnvelope"
+      kzg_proofs:
+        $ref: "../fulu/block_contents.yaml#/Fulu/KZGProofs"
+      blobs:
+        $ref: "../deneb/block_contents.yaml#/Deneb/Blobs"