diff --git a/apis/builder_config.yaml b/apis/builder_config.yaml
index 6805352..39446ae 100644
--- a/apis/builder_config.yaml
+++ b/apis/builder_config.yaml
@@ -39,7 +39,7 @@ get:
                   builder_boost_factor: "100"
                   builders:
                   - url: "https://builder-a.example.com"
-                    auth_data: "0x68747470733a2f2f6275696c6465722d612e6578616d706c652e636f6d"
+                    auth_data: "0x6275696c6465722d612e6578616d706c652e636f6d"
                     builder_pubkeys: []
                     max_execution_payment: "0"
                     min_bid: "20000000"
diff --git a/types/builder_entry.yaml b/types/builder_entry.yaml
index 0705b98..7ed3342 100644
--- a/types/builder_entry.yaml
+++ b/types/builder_entry.yaml
@@ -85,15 +85,16 @@ BuilderEntry:
 
         The keymanager treats this value as opaque bytes: it only ever compares `auth_data` values
         for equality, and never parses or inspects them. When no value has been agreed with the
-        builder out of band, the caller SHOULD set `auth_data` to the UTF-8 bytes of the builder's
-        own advertised URL, exactly as advertised, hex encoded: it is deterministic, distinct per
-        builder, and requires no coordination between the signers of a distributed validator. That
-        is purely a convention about what tooling writes into the field.
+        builder out of band, the caller SHOULD set `auth_data` to the hex encoded
+        [default auth data](https://github.com/ethereum/builder-specs/blob/main/specs/gloas/validator.md#default-auth-data)
+        derived from the builder URL, its hostname: it is deterministic, distinct per builder, and
+        requires no coordination between the signers of a distributed validator. That is purely a
+        convention about what tooling writes into the field.
 
-        Omitting it leaves the validator client to set it to the UTF-8 bytes of the entry's
-        `url` verbatim, since the builder requires authentication on every bid request. A
-        zero-length `auth_data` is invalid.
-      example: "0x68747470733a2f2f6275696c6465722e6578616d706c652e636f6d"
+        Omitting it leaves the validator client to derive it from the entry's `url` the same way,
+        since the builder requires authentication on every bid request. A zero-length `auth_data`
+        is invalid.
+      example: "0x6275696c6465722e6578616d706c652e636f6d"
     builder_pubkeys:
       type: array
       maxItems: 64  # MAX_BUILDER_PUBKEYS
diff --git a/wordlist.txt b/wordlist.txt
index a0452a3..ac7b136 100644
--- a/wordlist.txt
+++ b/wordlist.txt
@@ -21,6 +21,5 @@ oapi
 Vero
 Gwei
 uri
-UTF
 BuilderRequestAuth
 produceBlockV