diff --git a/pkg/container/SPEC.md b/pkg/container/SPEC.md
index 9f92720..7cd6d5d 100644
--- a/pkg/container/SPEC.md
+++ b/pkg/container/SPEC.md
@@ -27,7 +27,9 @@ The UCAN spec itself is transport agnostic. This specification describes how to
 
 UCAN tokens, regardless of their kind ([Delegation], [Invocation], [Revocation], [Promise]) MUST be first signed and serialized into DAG-CBOR bytes according to their respective specification. As the token's CID is not part of the serialized container, any CID returned by this operation is to be ignored.
 
-All the tokens' bytes MUST be assembled in a [CBOR] array, which is then inserted as the value under the `ctn-v1` string key, in a CBOR map. The ordering of tokens in the array MUST NOT matter. Also, this array SHOULD NOT have duplicate entries.
+All the tokens' bytes MUST be assembled in a [CBOR] array. The ordering of tokens in the array MUST NOT matter. This array SHOULD NOT have duplicate entries.
+
+That array is then inserted as the value under the `ctn-v1` string key, in a CBOR map. There MUST NOT be other keys.
 
 For clarity, the CBOR shape is given below: