hack: bluesky-social/pds handles rpc scopes a very specific way

crates/atproto-oauth/src/scopes.rs

···
                     } else {
                         "rpc:*".to_string()
                     }
+                } else if scope.lxm.len() == 1 && scope.aud.len() == 1 {
+                    // Single lxm and single aud (aud is not All, handled above)
+                    if let (Some(lxm), Some(aud)) =
+                        (scope.lxm.iter().next(), scope.aud.iter().next())
+                    {
+                        match (lxm, aud) {
+                            (RpcLexicon::Nsid(nsid), RpcAudience::Did(did)) => {
+                                format!("rpc:{}?aud={}", nsid, did)
+                            }
+                            (RpcLexicon::All, RpcAudience::Did(did)) => {
+                                format!("rpc:*?aud={}", did)
+                            }
+                            _ => "rpc:*".to_string(),
+                        }
+                    } else {
+                        "rpc:*".to_string()
+                    }
                 } else {
                     let mut params = Vec::new();
 
···
             ("repo:foo.bar", "repo:foo.bar"),
             ("repo:foo.bar?action=create", "repo:foo.bar?action=create"),
             ("rpc:*", "rpc:*"),
+            ("rpc:com.example.service", "rpc:com.example.service"),
+            (
+                "rpc:com.example.service?aud=did:example:123",
+                "rpc:com.example.service?aud=did:example:123",
+            ),
         ];
 
         for (input, expected) in tests {
···
 
         // Test with complex scopes including query parameters
         let scopes = vec![
-            Scope::parse("rpc:com.example.service?aud=did:example:123&lxm=com.example.method")
-                .unwrap(),
+            Scope::parse("rpc:com.example.service?aud=did:example:123").unwrap(),
             Scope::parse("repo:foo.bar?action=create&action=update").unwrap(),
             Scope::parse("blob:image/*?accept=image/png&accept=image/jpeg").unwrap(),
         ];
         let result = Scope::serialize_multiple(&scopes);
         // The result should be sorted alphabetically
-        // Note: RPC scope with query params is serialized as "rpc?aud=...&lxm=..."
+        // Single lxm + single aud is serialized as "rpc:[lxm]?aud=[aud]"
         assert!(result.starts_with("blob:"));
         assert!(result.contains(" repo:"));
-        assert!(result.contains("rpc?aud=did:example:123&lxm=com.example.service"));
+        assert!(result.contains("rpc:com.example.service?aud=did:example:123"));
 
         // Test with transition scopes
         let scopes = vec![