fix: MCP output types, requirement target extraction (#1435)

The `isinstance(target, Sequence)` check introduced in commit 3b90dae
incorrectly treats a single string target as a sequence of characters,
splitting it into individual chars. Fix that.

Signed-off-by: Nikola Forró <nforro@redhat.com>

Author: nforro

python/beeai_framework/adapters/mcp/serve/server.py

@@ -173,7 +173,7 @@ async def run(**kwargs: Any) -> MCPCallToolResult:
 
         return MCPCallToolResult(
             content=[MCPTextContent(type="text", text=output.get_text_content())],
-            structuredContent=to_json_serializable(output)
+            structuredContent=(res if isinstance(res := to_json_serializable(output), dict) else {"result": res})
             if isinstance(output, CustomJsonDump)  # (eg: JSONToolOutput/SearchToolOutput)
             else None,
             _meta={"is_empty": output.is_empty()},

python/beeai_framework/agents/requirement/requirements/_utils.py

@@ -16,7 +16,13 @@
 def _extract_targets(
     target: MultiTargetType | None,
 ) -> set[str | type | AnyTool]:
-    targets = list(target) if isinstance(target, Sequence) else [target] if target is not None else []
+    targets = (
+        list(target)
+        if isinstance(target, Sequence) and not isinstance(target, str)
+        else [target]
+        if target is not None
+        else []
+    )
     return set(targets)