fix: address Gemini Code Assist review feedback

- Fix critical **kwargs issue in get_dns_aid_tools() wrappers: _publish
  and _unpublish now have explicit parameter signatures so FunctionTool
  can introspect them for LLM tool schemas
- Add proper type hints: AgentRecord instead of Any, list['FunctionTool']
  return type
- Move imports to module level in A2A bridge
- Extract A2A_AGENT_CARD_PATH constant (no magic strings)

Author: IngmarVG-IB

src/google/adk/tools/dns_aid_a2a_bridge.py

@@ -9,8 +9,13 @@
 
 from typing import Any
 
+from dns_aid.core.models import AgentRecord, Protocol
 
-async def a2a_agent_from_record(agent_record: Any) -> dict[str, Any]:
+# Well-known path for A2A agent cards per the A2A specification.
+A2A_AGENT_CARD_PATH = "/.well-known/agent-card.json"
+
+
+async def a2a_agent_from_record(agent_record: AgentRecord) -> dict[str, Any]:
     """Convert a DNS-AID AgentRecord with A2A protocol to an ADK-compatible reference.
 
     Args:
@@ -22,8 +27,6 @@ async def a2a_agent_from_record(agent_record: Any) -> dict[str, Any]:
     Raises:
         ValueError: If the agent record is not using A2A protocol.
     """
-    from dns_aid.core.models import Protocol
-
     if agent_record.protocol != Protocol.A2A:
         raise ValueError(
             f"Agent {agent_record.name} uses protocol {agent_record.protocol}, not A2A"
@@ -36,5 +39,5 @@ async def a2a_agent_from_record(agent_record: Any) -> dict[str, Any]:
         "capabilities": agent_record.capabilities or [],
         "description": agent_record.description,
         "protocol": "a2a",
-        "a2a_card_url": f"{base_url}/.well-known/agent-card.json",
+        "a2a_card_url": f"{base_url}{A2A_AGENT_CARD_PATH}",
     }

src/google/adk/tools/dns_aid_tool.py

@@ -117,7 +117,7 @@ async def unpublish_agent(
     )
 
 
-def get_dns_aid_tools(backend_name: Optional[str] = None) -> list:
+def get_dns_aid_tools(backend_name: Optional[str] = None) -> list["FunctionTool"]:
     """Return DNS-AID tools wrapped as Google ADK FunctionTool objects.
 
     Args:
@@ -127,12 +127,43 @@ def get_dns_aid_tools(backend_name: Optional[str] = None) -> list:
 
     tools = [FunctionTool(discover_agents)]
     if backend_name:
-        # Create closures that bind the backend_name
-        async def _publish(**kwargs):  # type: ignore[no-untyped-def]
-            return await publish_agent(backend_name=backend_name, **kwargs)
-
-        async def _unpublish(**kwargs):  # type: ignore[no-untyped-def]
-            return await unpublish_agent(backend_name=backend_name, **kwargs)
+        # Create closures that bind the backend_name with explicit signatures
+        # so FunctionTool can introspect parameters for the LLM tool schema.
+        async def _publish(
+            agent_name: str,
+            domain: str,
+            protocol: str = "mcp",
+            endpoint: str = "",
+            port: int = 443,
+            capabilities: Optional[list[str]] = None,
+            version: str = "1.0.0",
+            description: Optional[str] = None,
+            ttl: int = 3600,
+        ) -> str:
+            return await publish_agent(
+                backend_name=backend_name,
+                agent_name=agent_name,
+                domain=domain,
+                protocol=protocol,
+                endpoint=endpoint,
+                port=port,
+                capabilities=capabilities,
+                version=version,
+                description=description,
+                ttl=ttl,
+            )
+
+        async def _unpublish(
+            agent_name: str,
+            domain: str,
+            protocol: str = "mcp",
+        ) -> str:
+            return await unpublish_agent(
+                backend_name=backend_name,
+                agent_name=agent_name,
+                domain=domain,
+                protocol=protocol,
+            )
 
         _publish.__name__ = "publish_agent"
         _publish.__doc__ = publish_agent.__doc__