fix: json import moved to top-level, doc token inprovement

Signed-off-by: Marek Dano <Marek.Dano@ibm.com>

Author: Marek Dano

docs/docs/using/agents/a2a.md

@@ -253,13 +253,14 @@ Before running the demo agent, ensure the following configuration:
 make dev
 
 # Terminal 2: Start the demo agent (auto-registers with ContextForge)
-# Option 1: Let the script generate the token
+# Option 1: Let the script generate the token internally
 PLATFORM_ADMIN_EMAIL=admin@example.com uv run python scripts/demo_a2a_agent.py
 
-# Option 2: Generate token manually (recommended for scripted access)
+# Option 2: Generate token manually for testing API calls (script still generates its own token)
 export TOKEN=$(python -m mcpgateway.utils.create_jwt_token \
   --username "admin@example.com" --exp 60)
 uv run python scripts/demo_a2a_agent.py
+# The $TOKEN variable is now available for the curl test commands below
 ```
 
 Note: The token generation uses your configured `JWT_SECRET_KEY` from `.env` (defaults to `my-test-key` for local development).

scripts/demo_a2a_agent.py

@@ -16,6 +16,7 @@
 """
 
 import atexit
+import json
 import os
 import random
 import signal
@@ -167,7 +168,6 @@ async def run_agent(request: Request) -> Response:
     body = await request.body()
     print(f"Raw request body: {body.decode('utf-8')}")
 
-    import json
     body_dict = json.loads(body)
 
     query_text = ""

scripts/demo_a2a_agent_auth.py

@@ -334,19 +334,19 @@ def run(self, query: str) -> str:
 class Parameters(BaseModel):
     """Parameters object containing the actual query."""
 
-    query: str = ""
-    message: str = ""
+    query: Optional[str] = None
+    message: Optional[str] = None
 
 
 class A2ARequest(BaseModel):
     """Request model for A2A protocol format (ContextForge custom agent format)."""
 
-    interaction_type: str = ""
+    interaction_type: Optional[str] = None
     parameters: Optional[Parameters] = None
-    protocol_version: str = ""
+    protocol_version: Optional[str] = None
     # Also support direct query/message for simple testing
-    query: str = ""
-    message: str = ""
+    query: Optional[str] = None
+    message: Optional[str] = None
 
 
 class MessagePart(BaseModel):