refactor: single dependency probe in capability detection; real test coverage

detect_mode_availability accepts a pre-computed dep_status so the agent
probes once; interface and fallback paths now have content-level tests.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

intercept_agent.py

@@ -423,27 +423,31 @@ class ModeManager:
         # Detect interfaces via shared capability detection
         capabilities["interfaces"] = detect_interfaces()
 
+        # Probe dependencies once; reuse for both mode availability and tool_details.
+        dep_status: dict | None = None
+        if HAS_DEPENDENCIES_MODULE:
+            try:
+                dep_status = check_all_dependencies()
+            except Exception as e:
+                logger.warning(f"Tool detail collection failed: {e}")
+
         # Detect mode availability via shared capability detection
-        raw_modes = detect_mode_availability()
+        raw_modes = detect_mode_availability(dep_status)
         for mode, ready in raw_modes.items():
             # Apply this agent's per-mode config gating on top of tool readiness
             capabilities["modes"][mode] = ready if config.modes_enabled.get(mode, True) else False
 
         # Populate detailed tool info for modes tracked in dependencies.py
-        if HAS_DEPENDENCIES_MODULE:
-            try:
-                dep_status = check_all_dependencies()
-                for dep_mode, cap_mode in MODE_DEPENDENCY_MAP.items():
-                    if dep_mode in dep_status:
-                        mode_info = dep_status[dep_mode]
-                        capabilities["tool_details"][cap_mode] = {
-                            "name": mode_info["name"],
-                            "ready": mode_info["ready"],
-                            "missing_required": mode_info["missing_required"],
-                            "tools": mode_info["tools"],
-                        }
-            except Exception as e:
-                logger.warning(f"Tool detail collection failed: {e}")
+        if dep_status is not None:
+            for dep_mode, cap_mode in MODE_DEPENDENCY_MAP.items():
+                if dep_mode in dep_status:
+                    mode_info = dep_status[dep_mode]
+                    capabilities["tool_details"][cap_mode] = {
+                        "name": mode_info["name"],
+                        "ready": mode_info["ready"],
+                        "missing_required": mode_info["missing_required"],
+                        "tools": mode_info["tools"],
+                    }
 
         # Use Intercept's SDR detection
         sdr_factory = self._get_sdr_factory()

tests/test_capabilities.py

@@ -1,6 +1,6 @@
 """Tests for shared capability detection."""
 
-from unittest.mock import patch
+from unittest.mock import MagicMock, patch
 
 from utils.capabilities import detect_interfaces, detect_mode_availability
 
@@ -34,10 +34,90 @@ class TestModeAvailability:
             modes = detect_mode_availability()
         assert modes.get("sensor") is False
 
+    def test_pre_computed_dep_status_skips_probe(self):
+        """Passing dep_status must not trigger a second check_all_dependencies call."""
+        pre_computed = {
+            key: {"ready": True}
+            for key in (
+                "pager",
+                "sensor",
+                "aircraft",
+                "ais",
+                "acars",
+                "aprs",
+                "wifi",
+                "bluetooth",
+                "tscm",
+                "satellite",
+            )
+        }
+        with patch("utils.capabilities.check_all_dependencies") as mock_deps:
+            modes = detect_mode_availability(dep_status=pre_computed)
+        mock_deps.assert_not_called()
+        assert modes.get("sensor") is True
+        assert modes.get("adsb") is True
+
 
 class TestInterfaceDetection:
-    def test_returns_expected_shape(self, fake_process):
-        with patch("subprocess.Popen", return_value=fake_process()):
+    def test_darwin_wifi_parsing(self):
+        """The Darwin branch must parse a Wi-Fi device out of networksetup output."""
+        networksetup_output = (
+            "Hardware Port: Wi-Fi\n"
+            "Device: en0\n"
+            "Ethernet Address: aa:bb:cc:dd:ee:ff\n"
+            "\n"
+            "Hardware Port: Thunderbolt Bridge\n"
+            "Device: bridge0\n"
+        )
+
+        def fake_run(cmd, **kwargs):
+            result = MagicMock()
+            result.stdout = networksetup_output
+            result.stderr = ""
+            result.returncode = 0
+            return result
+
+        with (
+            patch("utils.capabilities.platform.system", return_value="Darwin"),
+            patch("subprocess.run", side_effect=fake_run),
+        ):
             interfaces = detect_interfaces()
-        assert set(interfaces) == {"wifi_interfaces", "bt_adapters", "sdr_devices"}
-        assert isinstance(interfaces["wifi_interfaces"], list)
+
+        names = [i["name"] for i in interfaces["wifi_interfaces"]]
+        assert "en0" in names
+        # Verify the full shape of the parsed entry
+        en0 = next(i for i in interfaces["wifi_interfaces"] if i["name"] == "en0")
+        assert "display_name" in en0
+        assert "type" in en0
+        assert "monitor_capable" in en0
+        # Thunderbolt Bridge must not appear — it has no Wi-Fi/AirPort keyword
+        assert "bridge0" not in names
+
+
+class TestFallback:
+    def test_fallback_uses_check_tool(self):
+        """When check_all_dependencies raises, fall back to per-tool checks."""
+        with (
+            patch(
+                "utils.capabilities.check_all_dependencies",
+                side_effect=RuntimeError("module unavailable"),
+            ),
+            patch("utils.capabilities.check_tool", return_value=False) as mock_check,
+        ):
+            modes = detect_mode_availability()
+        assert modes.get("sensor") is False
+        assert mock_check.called
+
+    def test_fallback_extra_mode_tools(self):
+        """EXTRA_MODE_TOOLS modes (dsc, rtlamr, listening_post) reflect check_tool's return."""
+        with (
+            patch(
+                "utils.capabilities.check_all_dependencies",
+                side_effect=RuntimeError("module unavailable"),
+            ),
+            patch("utils.capabilities.check_tool", return_value=False),
+        ):
+            modes = detect_mode_availability()
+        assert modes.get("dsc") is False
+        assert modes.get("rtlamr") is False
+        assert modes.get("listening_post") is False

utils/capabilities.py

@@ -60,15 +60,21 @@ FALLBACK_TOOL_CHECKS = {
 }
 
 
-def detect_mode_availability() -> dict[str, bool]:
+def detect_mode_availability(dep_status: dict | None = None) -> dict[str, bool]:
     """Detect mode availability from tool dependencies.
 
     Returns a ``{cap_mode: bool}`` map of raw tool readiness. Falls back to
     direct tool checks if :func:`check_all_dependencies` raises.
+
+    Args:
+        dep_status: Pre-computed result of :func:`check_all_dependencies`.  When
+            supplied the probe is skipped entirely, avoiding a second call when
+            the caller has already fetched it.
     """
     modes: dict[str, bool] = {}
     try:
-        dep_status = check_all_dependencies()
+        if dep_status is None:
+            dep_status = check_all_dependencies()
     except Exception as e:
         logger.warning(f"Dependency check failed, using fallback: {e}")
         return _detect_mode_availability_fallback()