fix: address CodeRabbit review comments on agents config layer

- Avoid input dict mutation in AgentsConfig.extract_agent_definitions by
  shallow-copying before pop
- Use agents.update(value) instead of agents = value to merge rather
  than overwrite collected agent definitions
- Add mcp_headers field to HttpApiAgentConfig so api-to-agents migration
  preserves MCP headers instead of silently dropping them
- Remove field filtering in migrate_api_to_agents since all APIConfig
  fields now have corresponding HttpApiAgentConfig fields
- Add field_validator on EvaluationData.agent to reject whitespace-only
  agent names

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: rioloc

src/lightspeed_evaluation/core/models/agents.py

@@ -61,6 +61,10 @@ class HttpApiAgentConfig(BaseModel):
         ge=0,
         description="Maximum number of retry attempts for 429 errors",
     )
+    mcp_headers: Optional[dict[str, Any]] = Field(
+        default=None,
+        description="MCP headers configuration for authentication",
+    )
 
     @field_validator("endpoint_type")
     @classmethod
@@ -112,13 +116,14 @@ def extract_agent_definitions(cls, data: Any) -> Any:
         if not isinstance(data, dict):
             return data
 
+        data = dict(data)
         agents: dict[str, Any] = {}
         default_data = data.pop("default", {})
         remaining: dict[str, Any] = {}
 
         for key, value in data.items():
             if key == "agents":
-                agents = value
+                agents.update(value)
             elif isinstance(value, dict) and "type" in value:
                 agents[key] = value
             else:

src/lightspeed_evaluation/core/models/data.py

@@ -423,6 +423,14 @@ def is_metric_invalid(self, metric: str) -> bool:
         """Returns True if the metric didn't pass the validation."""
         return metric in self._invalid_metrics
 
+    @field_validator("agent")
+    @classmethod
+    def validate_agent_not_whitespace(cls, v: Optional[str]) -> Optional[str]:
+        """Validate agent name is not whitespace-only."""
+        if v is not None and not v.strip():
+            raise ValueError("agent name cannot be empty or whitespace")
+        return v
+
     @field_validator("conversation_metrics")
     @classmethod
     def validate_conversation_metrics(

src/lightspeed_evaluation/core/models/system.py

@@ -39,7 +39,7 @@
     SUPPORTED_ENDPOINT_TYPES,
     SUPPORTED_GRAPH_TYPES,
 )
-from lightspeed_evaluation.core.models.agents import AgentsConfig, HttpApiAgentConfig
+from lightspeed_evaluation.core.models.agents import AgentsConfig
 from lightspeed_evaluation.core.storage.config import StorageBackendConfig
 from lightspeed_evaluation.core.system.exceptions import ConfigurationError
 
@@ -874,18 +874,12 @@ def migrate_api_to_agents(cls, data: Any) -> Any:
             return data
 
         api_data = data["api"]
-        valid_fields = set(HttpApiAgentConfig.model_fields.keys())
         if isinstance(api_data, dict):
             api_enabled = api_data.get("enabled", True)
-            agent_fields = {
-                k: v
-                for k, v in api_data.items()
-                if k != "enabled" and k in valid_fields
-            }
+            agent_fields = {k: v for k, v in api_data.items() if k != "enabled"}
         elif isinstance(api_data, BaseModel):
             api_enabled = getattr(api_data, "enabled", True)
-            dumped = api_data.model_dump(exclude={"enabled"})
-            agent_fields = {k: v for k, v in dumped.items() if k in valid_fields}
+            agent_fields = api_data.model_dump(exclude={"enabled"})
         else:
             return data
 

tests/unit/core/models/test_agents.py

@@ -67,6 +67,21 @@ def test_num_retries_must_be_non_negative(self) -> None:
         with pytest.raises(ValidationError):
             HttpApiAgentConfig(num_retries=-1)
 
+    def test_mcp_headers_accepted(self) -> None:
+        """Test mcp_headers field is accepted."""
+        config = HttpApiAgentConfig(
+            mcp_headers={"enabled": True, "servers": {"mcp1": {"env_var": "TOKEN"}}}
+        )
+        assert config.mcp_headers == {
+            "enabled": True,
+            "servers": {"mcp1": {"env_var": "TOKEN"}},
+        }
+
+    def test_mcp_headers_defaults_to_none(self) -> None:
+        """Test mcp_headers defaults to None."""
+        config = HttpApiAgentConfig()
+        assert config.mcp_headers is None
+
     def test_extra_forbid(self) -> None:
         """Test unknown fields are rejected."""
         with pytest.raises(ValidationError):
@@ -167,6 +182,17 @@ def test_unknown_top_level_key_rejected(self) -> None:
                 }
             )
 
+    def test_input_dict_not_mutated(self) -> None:
+        """Test that the input dict is not mutated by the model validator."""
+        input_data = {
+            "default": {"agent": "ols_api"},
+            "ols_api": {"type": "http_api"},
+        }
+        original_keys = set(input_data.keys())
+        AgentsConfig.model_validate(input_data)
+        assert set(input_data.keys()) == original_keys
+        assert "default" in input_data
+
 
 class TestAgentsConfigResolve:
     """Tests for AgentsConfig.resolve_agent_config method."""

tests/unit/core/models/test_data.py

@@ -687,3 +687,12 @@ def test_empty_agent_name_rejected(self) -> None:
                 agent="",
                 turns=[TurnData(turn_id="t1", query="Q")],
             )
+
+    def test_whitespace_agent_name_rejected(self) -> None:
+        """Whitespace-only agent name is rejected."""
+        with pytest.raises(ValidationError, match="agent name cannot be empty"):
+            EvaluationData(
+                conversation_group_id="cg1",
+                agent="   ",
+                turns=[TurnData(turn_id="t1", query="Q")],
+            )

tests/unit/core/models/test_system.py

@@ -775,3 +775,20 @@ def test_invalid_default_agent_reference_raises(self) -> None:
                     agents={"ols_api": HttpApiAgentConfig()},
                 )
             )
+
+    def test_mcp_headers_preserved_during_migration(self) -> None:
+        """mcp_headers from api: are preserved in the migrated agents config."""
+        config = SystemConfig.model_validate(
+            {
+                "api": {
+                    "enabled": True,
+                    "mcp_headers": {
+                        "enabled": True,
+                        "servers": {},
+                    },
+                },
+            }
+        )
+        assert config.agents is not None
+        agent = config.agents.agents["http_api"]
+        assert agent.mcp_headers == {"enabled": True, "servers": {}}