Merge pull request modelcontextprotocol#415 from evalstate/fix/tool-resource-guidance

Update guidance for use of Embedded Resources in CallToolResult

Author: bhosmer-ant

docs/specification/draft/server/resources.mdx

@@ -326,6 +326,11 @@ otherwise have a standard MIME type.
 
 Git version control integration.
 
+### Custom URI Schemes
+
+Custom URI schemes **MUST** be in accordance with [RFC3986](https://datatracker.ietf.org/doc/html/rfc3986),
+taking the above guidance in to account.
+
 ## Error Handling
 
 Servers **SHOULD** return standard JSON-RPC errors for common failure cases:

docs/specification/draft/server/tools.mdx

@@ -252,8 +252,8 @@ or data. In this case, the tool will return a URI that can be subscribed to or f
 
 #### Embedded Resources
 
-A tool **MAY** return embedded [Resource contents](/specification/draft/server/resources), to provide additional context
-or data, along with a URI that can be subscribed to or fetched again by the client later:
+[Resources](resources) **MAY** be embedded to provide additional context
+or data using a suitable [URI scheme](./resources#common-uri-schemes). Servers that use embedded resources **SHOULD** implement the `resources` capability:
 
 ```json
 {