Merge pull request modelcontextprotocol#889 from modelcontextprotocol/fix/struct-guidance

Simplify backward compatibility wording for Structured Outputs

Author: bhosmer-ant

docs/specification/2025-06-18/server/tools.mdx

@@ -273,8 +273,7 @@ or data using a suitable [URI scheme](./resources#common-uri-schemes). Servers t
 
 **Structured** content is returned as a JSON object in the `structuredContent` field of a result.
 
-For backwards compatibility, a tool that returns structured content SHOULD also return functionally equivalent unstructured content.
-(For example, serialized JSON can be returned in a `TextContent` block.)
+For backwards compatibility, a tool that returns structured content SHOULD also return the serialized JSON in a TextContent block.
 
 #### Output Schema
 

docs/specification/draft/server/tools.mdx

@@ -273,8 +273,7 @@ or data using a suitable [URI scheme](./resources#common-uri-schemes). Servers t
 
 **Structured** content is returned as a JSON object in the `structuredContent` field of a result.
 
-For backwards compatibility, a tool that returns structured content SHOULD also return functionally equivalent unstructured content.
-(For example, serialized JSON can be returned in a `TextContent` block.)
+For backwards compatibility, a tool that returns structured content SHOULD also return the serialized JSON in a TextContent block.
 
 #### Output Schema