Coerce AgentPolicyConfig fields to string (fixes #169)

CHANGELOG.md

@@ -512,6 +512,11 @@ All notable changes to this project are documented here. The format is based on
   regression (`eef_delta_pose` + `rot6d` already reached the displacement
   clamp path before #143/#144). `euler_xyz` and `axis_angle` deltas have no
   such problem and remain guardrail-conformant.
+- **Agent policy configuration parameters now strictly reject non-strings**
+  in `LLMAgentPolicy` constructor, raising a guided `ConfigError` (#169). This
+  prevents unquoted CLI values (e.g., `-P model=42` or `-P api_key_env=false`)
+  from causing downstream errors or incorrect fallback logic, prompting the
+  user to pass quoted strings instead.
 - **An explicit invalid `--max-action-delta` now fails fast instead of silently
   running with weaker guardrails** (#154). Non-finite or non-positive values
   were previously caught by `_build_guardrails`'s degrade-per-component path

plugins/inspect-robots-agent/src/inspect_robots_agent/policy.py

@@ -333,6 +333,23 @@ def __init__(
         env: dict[str, str] | None = None,
         pre_check: PreCheck | None = None,
     ) -> None:
+        # Reject non-strings with a guided ConfigError to prevent unquoted CLI
+        # values (e.g. -P model=42) from causing downstream errors or silent bypasses.
+        for name, val in [
+            ("model", model),
+            ("base_url", base_url),
+            ("api_key_env", api_key_env),
+            ("speed", speed),
+        ]:
+            if isinstance(val, _Unset):
+                continue
+            if val is not None and not isinstance(val, str):
+                raise ConfigError(
+                    f"{name} must be a string, got {val!r}.\n"
+                    f"fix: the -P parser coerces unquoted values; pass "
+                    f"-P '{name}=\"value\"'"
+                )
+
         prior_learnings_path: str | None = None
         prior_learnings_text: str | None = None
         prior_learnings_sha256: str | None = None

plugins/inspect-robots-agent/tests/test_anthropic.py

@@ -1287,20 +1287,19 @@ def test_variant_strip_keeps_fine_tune_colons() -> None:
         )
 
 
-@pytest.mark.parametrize("api_key_env", [None, "", False, 0, 0.0])
+@pytest.mark.parametrize("api_key_env", [None, ""])
 def test_falsy_api_key_env_does_not_send_the_openrouter_key_to_a_gateway(
-    api_key_env: object,
+    api_key_env: str | None,
 ) -> None:
-    # '-P api_key_env=' parses to '', and 'false'/'0' to other falsy values,
-    # all of which resolve_provider treats as unset and answers with
-    # $OPENROUTER_API_KEY. An `is None` test would hand a third-party gateway
-    # the OpenRouter secret.
+    # '-P api_key_env=' parses to '', which resolve_provider treats as unset
+    # and answers with $OPENROUTER_API_KEY. An `is None` test would hand a
+    # third-party gateway the OpenRouter secret.
     seen, handler = _capture(_anthropic_response(_text("ok"), stop_reason="end_turn"))
     policy = LLMAgentPolicy(
         model="claude-opus-5",
         wire="messages",
         base_url="https://gw.example/v1",
-        api_key_env=api_key_env,  # type: ignore[arg-type]
+        api_key_env=api_key_env,
         transport=httpx.MockTransport(handler),
         env={"ANTHROPIC_API_KEY": "sk-ant", "OPENROUTER_API_KEY": "sk-or"},
     )

plugins/inspect-robots-agent/tests/test_policy_e2e.py

@@ -2791,3 +2791,40 @@ def test_chat_wire_usage_metadata_counts_calls_only(tmp_path: Path) -> None:
     )
 
     assert sink.records[0].metadata["llm_usage"] == {"llm_calls": 2}
+
+
+def test_non_string_params_rejected() -> None:
+    for param, val in [
+        ("model", 42),
+        ("model", 0),
+        ("base_url", True),
+        ("base_url", False),
+        ("api_key_env", True),
+        ("api_key_env", False),
+        ("speed", False),
+    ]:
+        kwargs: dict[str, Any] = {
+            "model": "test-model",
+            "base_url": "http://localhost:8000",
+            "api_key_env": "TEST_KEY",
+            "effort": "low",
+            "speed": None,
+            "wire": "chat",
+        }
+        kwargs[param] = val
+
+        # speed requires wire='anthropic'
+        if param == "speed":
+            kwargs["wire"] = "anthropic"
+
+        with pytest.raises(ConfigError) as exc_info:
+            LLMAgentPolicy(**kwargs)
+
+        assert f"{param} must be a string, got {val!r}." in str(exc_info.value)
+        expected_fix = f"fix: the -P parser coerces unquoted values; pass -P '{param}=\"value\"'"
+        assert expected_fix in str(exc_info.value)
+
+
+def test_policy_config_defaults() -> None:
+    policy = LLMAgentPolicy(model="anthropic/claude-3-5-sonnet", base_url="http://localhost:8000")
+    assert policy._pre_check is None

tests/test_rerun_sink.py

@@ -2,7 +2,6 @@
 
 from __future__ import annotations
 
-import importlib.util
 import inspect
 import re
 import socket
@@ -44,7 +43,12 @@
 from inspect_robots.task import Task
 from inspect_robots.types import Action, Observation, StepResult
 
-_RERUN_INSTALLED = importlib.util.find_spec("rerun") is not None
+try:
+    import rerun  # noqa: F401
+
+    _RERUN_INSTALLED = True
+except ImportError:
+    _RERUN_INSTALLED = False
 
 
 def _task() -> Task:
@@ -1842,7 +1846,10 @@ def test_real_rerun_accepts_the_blueprint(tmp_path: Path) -> None:
 
 def test_real_rerun_process_exits_when_tcp_peer_never_reads() -> None:
     """The real SDK atexit path is bounded after a connected peer stops reading."""
-    rr = pytest.importorskip("rerun")
+    if not _RERUN_INSTALLED:
+        pytest.skip("requires rerun-sdk")
+    import rerun as rr
+
     if not hasattr(rr, "connect_grpc"):
         pytest.skip("pre-gRPC rerun-sdk cannot run the connect-mode wedge scenario")
     server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)