diff --git a/buds/01.md b/buds/01.md
index c10a883..1b17cc5 100644
--- a/buds/01.md
+++ b/buds/01.md
@@ -79,6 +79,9 @@ The `GET /<sha256>` endpoint MUST return the contents of the blob in the respons
 
 The endpoint MUST accept an optional file extension in the URL. ie. `.pdf`, `.png`, etc
 
+Regardless of the file extension, the server MUST return the MIME type of the blob in the `Content-Type`
+header. If the server does not know the MIME type of the blob, it MUST default to `application/octet-stream`
+
 If the endpoint returns a `301` or `302` redirect it MUST redirect to a URL containing the same sha256 hash as the requested blob.
 This ensures that if a user was to copy or reuse the redirect URL it would still contain the original sha256 hash
 
diff --git a/buds/04.md b/buds/04.md
index dde6fc4..4f323c9 100644
--- a/buds/04.md
+++ b/buds/04.md
@@ -25,9 +25,14 @@ The `/mirror` endpoint MUST download the blob from the specified URL and verify
 
 **Multiple `x` tags in the authorization event MUST NOT be interpreted as the user requesting to mirror multiple blobs.**
 
-The endpoint MUST return a [Blob Descriptor](#blob-descriptor) and a `2xx` status code if the mirroring was successful or a `4xx` status code and error messageif it was not
+The endpoint MUST return a [Blob Descriptor](#blob-descriptor) and a `2xx` status code if the mirroring was successful
+or a `4xx` status code and error message if it was not.
 
-Servers SHOULD use the `Content-Type` header returned from the requested URL to infer the mime type of the blob. If the `Content-Type` header is not returned they SHOULD attempt to use the file extension in the URL or fallback to `application/octet-stream`.
+Servers SHOULD use the `Content-Type` header returned from the requested URL to infer the mime type of the blob. If the
+`Content-Type` header is not present they SHOULD attempt to detect the `Content-Type` from the blob contents and file
+extension, falling back to `application/octet-stream` if they cannot determine the type.
+
+Servers MAY use the `Content-Length` header to determine the size of the blob.
 
 Servers MAY reject a mirror request for any reason and MUST respond with the appropriate HTTP `4xx` status code and an error message explaining the reason for the rejection.