diff --git a/docs/api/authentication.md b/docs/api/authentication.md
index 69c7006b..0c588662 100644
--- a/docs/api/authentication.md
+++ b/docs/api/authentication.md
@@ -222,7 +222,7 @@ withdraw_balance(old_key)
 - Typo in API key
 - The credential is neither an `sk-...` key nor a `cashu...` token
 
-A well-formed `sk-...` key that this node has no record of is reported
+A credential starting with `sk-` that this node has no record of is reported
 separately as `key_not_found` (also 401) — see
 [Error Handling → Authentication Errors](errors.md#authentication-errors).
 
diff --git a/docs/api/errors.md b/docs/api/errors.md
index f87e802f..15dcd0b1 100644
--- a/docs/api/errors.md
+++ b/docs/api/errors.md
@@ -119,10 +119,10 @@ Returned when the `Authorization` value is neither an `sk-...` API key nor a
 preview and length (`Invalid API key format: preview=… length=…`) to distinguish
 a typo from a wrong-shaped header.
 
-#### API Key Not Found (well-formed but unknown to this node)
+#### API Key Not Found (`sk-` key unknown to this node)
 
-Returned when the credential is a well-formed `sk-...` key that this node has no
-record of — for example a key minted by a different Routstr node, or one removed
+Returned when the credential starts with `sk-` and this node has no record of
+it — for example a key minted by a different Routstr node, or one removed
 by key pruning. This is *not* a formatting problem.
 
 ```json
diff --git a/routstr/auth.py b/routstr/auth.py
index bb3f00f8..885b0ab9 100644
--- a/routstr/auth.py
+++ b/routstr/auth.py
@@ -293,12 +293,6 @@ async def _validate_bearer_key_locked(
                 "sk- API key not found in database",
                 extra={"key_preview": bearer_key[:10] + "..."},
             )
-            # The credential is a well-formed 'sk-...' API key: the format is
-            # valid and the failure is that the key does not exist on this node.
-            # Falling through to the generic handler below would report it as
-            # "Invalid API key format", sending callers after a formatting bug
-            # that does not exist. Report the real cause instead.
-            #
             # Keep the "Key not found." prefix verbatim: @routstr/sdk (<=0.4.6)
             # detects a dead key with a case-sensitive `body.includes("Key not
             # found")` probe, and uses it to purge the key from its store. The