diff --git a/bot_bottle/cli/commands/supervise.py b/bot_bottle/cli/commands/supervise.py
index cbb349f4..cd2c5b7d 100644
--- a/bot_bottle/cli/commands/supervise.py
+++ b/bot_bottle/cli/commands/supervise.py
@@ -368,7 +368,7 @@ def _main_loop(stdscr: "curses._CursesWindow") -> None:  # type: ignore  # pragm
         elif key in (curses.KEY_UP, ord("k")):
             selected = max(selected - 1, 0)
         elif key in (curses.KEY_ENTER, 10, 13):
-            _detail_view(stdscr, qp, green_attr=green_attr)
+            status_line = _detail_view(stdscr, qp, green_attr=green_attr)
         elif key == ord("a"):
             try:
                 status_line = _approve_from_tui(stdscr, qp)
@@ -456,7 +456,7 @@ def _detail_view(
     qp: QueuedProposal,
     *,
     green_attr: int = 0,
-) -> None:  # pragma: no cover
+) -> str:  # pragma: no cover
     """Render the full proposal. Scrollable. Press q to return."""
     lines = _detail_lines(qp, green_attr=green_attr)
     offset = 0
@@ -473,7 +473,7 @@ def _detail_view(
         stdscr.refresh()
         key = stdscr.getch()
         if key in (ord("q"), 27):
-            return
+            return ""
         if key in (curses.KEY_DOWN, ord("j")):
             offset = min(offset + 1, max(0, len(lines) - 1))
         elif key in (curses.KEY_UP, ord("k")):
@@ -484,28 +484,28 @@ def _detail_view(
             offset = max(0, len(lines) - 1)
         elif key == ord("a"):
             try:
-                _approve_from_tui(stdscr, qp)
-            except ApplyError:
-                pass
-            return
+                return _approve_from_tui(stdscr, qp)
+            except ApplyError as exc:
+                return f"apply failed: {exc}"
         elif key == ord("m"):
             if qp.proposal.tool in _REPORT_ONLY_TOOLS:
-                return
+                return f"modify unavailable for {qp.proposal.tool}"
             edited = _modify(stdscr, qp)
-            if edited is not None:
-                try:
-                    _approve_from_tui(
-                        stdscr, qp, final_file=edited,
-                        notes="operator modified before approving",
-                    )
-                except ApplyError:
-                    pass
-            return
+            if edited is None:
+                return "modify aborted (no change)"
+            try:
+                return _approve_from_tui(
+                    stdscr, qp, final_file=edited,
+                    notes="operator modified before approving",
+                )
+            except ApplyError as exc:
+                return f"apply failed: {exc}"
         elif key == ord("r"):
             reason = _prompt(stdscr, "reject reason: ")
             if reason:
                 reject(qp, reason=reason)
-            return
+                return f"rejected {qp.proposal.tool} for [{qp.label}]"
+            return "reject aborted (empty reason)"
 
 
 def _modify(stdscr: "curses._CursesWindow", qp: QueuedProposal) -> str | None:  # type: ignore  # pragma: no cover
diff --git a/bot_bottle/cli/tui.py b/bot_bottle/cli/tui.py
index 03cca8e3..e522d5c0 100644
--- a/bot_bottle/cli/tui.py
+++ b/bot_bottle/cli/tui.py
@@ -16,6 +16,8 @@ import os
 import sys
 from typing import Any, Optional
 
+from ..log import debug
+
 
 def filter_multiselect(
     items: list[str],
@@ -42,7 +44,11 @@ def filter_multiselect(
 
     try:
         tty_fd = open(tty_path, "r+b", buffering=0)
-    except OSError:
+    except OSError as exc:
+        debug(
+            "multi-select unavailable; treating it as cancellation",
+            context={"error_type": type(exc).__name__, "tty": tty_path},
+        )
         return None
 
     try:
@@ -73,7 +79,11 @@ def filter_select(
 
     try:
         tty_fd = open(tty_path, "r+b", buffering=0)
-    except OSError:
+    except OSError as exc:
+        debug(
+            "filter-select unavailable; treating it as cancellation",
+            context={"error_type": type(exc).__name__, "tty": tty_path},
+        )
         return None
 
     try:
@@ -129,7 +139,11 @@ def _run_picker(items: list[str], *, title: str, tty_fd: int) -> Optional[str]:
             curses.nocbreak()
             curses.echo()
             curses.endwin()
-    except Exception:  # noqa: W0718 — curses can raise many error types
+    except Exception as exc:  # noqa: W0718 — curses can raise many error types
+        debug(
+            "filter-select display failed; treating it as cancellation",
+            context={"error_type": type(exc).__name__},
+        )
         return None
     finally:
         sys.__stdin__ = orig_stdin    # type: ignore[assignment]
@@ -292,7 +306,11 @@ def _run_multiselect(
             curses.nocbreak()
             curses.echo()
             curses.endwin()
-    except Exception:  # noqa: W0718
+    except Exception as exc:  # noqa: W0718
+        debug(
+            "multi-select display failed; treating it as cancellation",
+            context={"error_type": type(exc).__name__},
+        )
         return None
     finally:
         sys.__stdin__ = orig_stdin    # type: ignore[assignment]
@@ -558,13 +576,21 @@ def name_color_modal(
     """
     try:
         tty_fd = open(tty_path, "r+b", buffering=0)  # pylint: disable=consider-using-with
-    except OSError:
+    except OSError as exc:
+        debug(
+            "name/color picker unavailable; using defaults",
+            context={"error_type": type(exc).__name__, "tty": tty_path},
+        )
         return default_label, ""
 
     try:
         fd_dup = os.dup(tty_fd.fileno())
         return _run_name_color(default_label, tty_fd=fd_dup, disclaimer=disclaimer)
-    except Exception:  # noqa: BLE001  # pylint: disable=broad-exception-caught
+    except Exception as exc:  # noqa: BLE001  # pylint: disable=broad-exception-caught
+        debug(
+            "name/color picker failed; using defaults",
+            context={"error_type": type(exc).__name__},
+        )
         return default_label, ""
     finally:
         tty_fd.close()
diff --git a/bot_bottle/gateway/egress/context.py b/bot_bottle/gateway/egress/context.py
index 630a0be3..48e7c515 100644
--- a/bot_bottle/gateway/egress/context.py
+++ b/bot_bottle/gateway/egress/context.py
@@ -4,6 +4,7 @@ from __future__ import annotations
 
 import typing
 
+from ...log import debug
 from .types import Config
 
 
@@ -52,7 +53,11 @@ def resolve_client_config(
 ) -> Config:
     try:
         policy = resolver.resolve(client_ip, identity_token)
-    except Exception:  # noqa: BLE001 - a policy lookup failure must deny
+    except Exception as exc:  # noqa: BLE001 - a policy lookup failure must deny
+        debug(
+            "egress policy resolution failed; applying deny-all",
+            context={"error_type": type(exc).__name__},
+        )
         return Config(routes=(), deny_reason=DENY_RESOLVER_ERROR)
     return _config_from_policy(policy)
 
@@ -63,6 +68,10 @@ def resolve_client_context(
     try:
         policy, bottle_id, tokens = resolver.resolve_policy_and_bottle_id(
             client_ip, identity_token)
-    except Exception:  # noqa: BLE001 - a policy lookup failure must deny
+    except Exception as exc:  # noqa: BLE001 - a policy lookup failure must deny
+        debug(
+            "egress context resolution failed; applying deny-all",
+            context={"error_type": type(exc).__name__},
+        )
         return Config(routes=(), deny_reason=DENY_RESOLVER_ERROR), "", {}
     return _config_from_policy(policy), (bottle_id or ""), tokens
diff --git a/bot_bottle/orchestrator/client.py b/bot_bottle/orchestrator/client.py
index 9d51a5a5..ce032364 100644
--- a/bot_bottle/orchestrator/client.py
+++ b/bot_bottle/orchestrator/client.py
@@ -18,6 +18,7 @@ import urllib.request
 from collections.abc import Iterable
 from dataclasses import dataclass
 
+from ..log import debug
 from ..orchestrator_auth import ROLE_CLI
 from ..trust_domain import CONTROL_PLANE
 from .server import ORCHESTRATOR_AUTH_HEADER
@@ -53,6 +54,23 @@ class RegisteredBottle:
     env_var_secret: str = ""
 
 
+@dataclass(frozen=True)
+class BackendProbeFailure:
+    """Safe diagnostic for an optional backend discovery probe."""
+
+    backend: str
+    error_type: str
+
+
+def _probe_failure(backend: str, exc: BaseException) -> BackendProbeFailure:
+    failure = BackendProbeFailure(backend, type(exc).__name__)
+    debug(
+        "orchestrator discovery probe unavailable",
+        context={"backend": failure.backend, "error_type": failure.error_type},
+    )
+    return failure
+
+
 class OrchestratorClient:
     """Trusted host-side client for the orchestrator control plane.
 
@@ -245,32 +263,41 @@ def discover_orchestrator_url(*, timeout: float = 2.0) -> str:
     orchestrator TAP. Returns the first that answers `/health`; raises if none
     do (no orchestrator up — launch a bottle first)."""
     candidates: list[str] = []
+    failures: list[BackendProbeFailure] = []
     try:  # docker: loopback-published control plane
         from .lifecycle import DEFAULT_PORT as _DOCKER_PORT
         candidates.append(f"http://127.0.0.1:{_DOCKER_PORT}")
-    except Exception:  # noqa: BLE001 — backend optional
+    except Exception as exc:  # noqa: BLE001 — backend optional
+        failures.append(_probe_failure("docker", exc))
         candidates.append("http://127.0.0.1:8099")
     try:  # firecracker: infra VM control plane on the orchestrator TAP
         from ..backend.firecracker import netpool
         from ..backend.firecracker.infra_vm import ORCHESTRATOR_PORT
         candidates.append(
             f"http://{netpool.orch_slot().guest_ip}:{ORCHESTRATOR_PORT}")
-    except Exception:  # noqa: BLE001 — backend optional / not firecracker
-        pass
+    except Exception as exc:  # noqa: BLE001 — backend optional / not firecracker
+        failures.append(_probe_failure("firecracker", exc))
     try:  # macOS: orchestrator container on its host-only address
         from ..backend.macos_container.infra import probe_orchestrator_url
         url = probe_orchestrator_url()
         if url:
             candidates.append(url)
-    except Exception:  # noqa: BLE001 — backend optional / not macOS
-        pass
+    except Exception as exc:  # noqa: BLE001 — backend optional / not macOS
+        failures.append(_probe_failure("macos-container", exc))
     for url in candidates:
         if OrchestratorClient(url, timeout=timeout).health():
             return url
+    detail = ""
+    if failures:
+        detail = "; optional probes unavailable: " + ", ".join(
+            f"{failure.backend} ({failure.error_type})" for failure in failures
+        )
     raise OrchestratorClientError(
         "no running orchestrator control plane found (tried "
         + ", ".join(candidates)
-        + "); launch a bottle first"
+        + ")"
+        + detail
+        + "; launch a bottle first"
     )
 
 
diff --git a/bot_bottle/orchestrator/reprovision.py b/bot_bottle/orchestrator/reprovision.py
index e55ebea0..31d6b172 100644
--- a/bot_bottle/orchestrator/reprovision.py
+++ b/bot_bottle/orchestrator/reprovision.py
@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+from ..log import debug
 from .client import OrchestratorClient, OrchestratorClientError
 
 
@@ -27,7 +28,14 @@ def reprovision_bottles(
         try:
             if client.reprovision_gateway(bottle_id, secret):
                 restored += 1
-        except OrchestratorClientError:
+        except OrchestratorClientError as exc:
+            debug(
+                "gateway secret reprovision failed; continuing with other bottles",
+                context={
+                    "bottle_id": bottle_id,
+                    "error_type": type(exc).__name__,
+                },
+            )
             continue
     return restored
 
diff --git a/bot_bottle/orchestrator/server.py b/bot_bottle/orchestrator/server.py
index cd36b55a..bead932b 100644
--- a/bot_bottle/orchestrator/server.py
+++ b/bot_bottle/orchestrator/server.py
@@ -379,9 +379,15 @@ class Handler(http.server.BaseHTTPRequestHandler):
             status, payload = dispatch(
                 server.orchestrator, method, self.path, body, role=role)
         except Exception as e:  # noqa: BLE001 — the control plane must stay up
-            sys.stderr.write(f"orchestrator: {method} {self.path} failed: {e!r}\n")
+            # Do not echo exception messages to the caller or logs: broker and
+            # persistence exceptions can contain request data. The operation,
+            # route, and exception type are enough to correlate a traceback.
+            sys.stderr.write(
+                f"orchestrator: {method} {self.path} failed "
+                f"[error_type={type(e).__name__}]\n"
+            )
             sys.stderr.flush()
-            status, payload = 500, {"error": f"internal error: {e}"}
+            status, payload = 500, {"error": "internal error"}
         data = json.dumps(payload).encode()
         self.send_response(status)
         self.send_header("Content-Type", "application/json")
diff --git a/tests/unit/test_architecture_guardrails.py b/tests/unit/test_architecture_guardrails.py
index 6efb0397..d937d188 100644
--- a/tests/unit/test_architecture_guardrails.py
+++ b/tests/unit/test_architecture_guardrails.py
@@ -34,6 +34,20 @@ class TestCliBackendBoundaries(unittest.TestCase):
 
 
 class TestRuntimeModuleSizes(unittest.TestCase):
+    def test_no_runtime_module_grows_beyond_global_ceiling(self) -> None:
+        """A coarse ceiling catches new monoliths; focused caps stay tighter."""
+        ceiling = 850
+        oversized = [
+            f"{path.relative_to(ROOT)} ({len(path.read_text().splitlines())})"
+            for path in (ROOT / "bot_bottle").rglob("*.py")
+            if len(path.read_text().splitlines()) > ceiling
+        ]
+        self.assertEqual(
+            [], oversized,
+            f"runtime modules must stay at or below {ceiling} lines: "
+            + ", ".join(oversized),
+        )
+
     def test_egress_modules_stay_focused(self) -> None:
         caps = {
             "addon_core.py": 100,
diff --git a/tests/unit/test_backend_secret_reprovision.py b/tests/unit/test_backend_secret_reprovision.py
index 3c25092c..7d74e197 100644
--- a/tests/unit/test_backend_secret_reprovision.py
+++ b/tests/unit/test_backend_secret_reprovision.py
@@ -48,12 +48,13 @@ class TestSharedReprovision(unittest.TestCase):
         client.reprovision_gateway.side_effect = [
             OrchestratorClientError("bad key"), True,
         ]
-        self.assertEqual(
-            1,
-            reprovision_bottles(
+        with patch("bot_bottle.orchestrator.reprovision.debug") as debug:
+            count = reprovision_bottles(
                 client, {"10.0.0.1": "key-1", "10.0.0.2": "key-2"},
-            ),
-        )
+            )
+        self.assertEqual(1, count)
+        self.assertEqual("b1", debug.call_args.kwargs["context"]["bottle_id"])
+        self.assertNotIn("bad key", repr(debug.call_args))
 
 
 class TestMacosReprovision(unittest.TestCase):
diff --git a/tests/unit/test_cli_tui.py b/tests/unit/test_cli_tui.py
index 605e9502..7a9d5dc4 100644
--- a/tests/unit/test_cli_tui.py
+++ b/tests/unit/test_cli_tui.py
@@ -9,6 +9,7 @@ from __future__ import annotations
 
 import unittest
 from typing import Any, Optional
+from unittest.mock import patch
 
 from bot_bottle.cli.tui import _filter_items, _multiselect_loop, filter_multiselect, filter_select
 
@@ -49,8 +50,10 @@ class TestFilterSelectEmptyItems(unittest.TestCase):
 
     def test_returns_none_when_tty_unavailable(self):
         # /nonexistent is guaranteed to not open.
-        result = filter_select(["a", "b"], tty_path="/nonexistent/tty")
+        with patch("bot_bottle.cli.tui.debug") as debug:
+            result = filter_select(["a", "b"], tty_path="/nonexistent/tty")
         self.assertIsNone(result)
+        self.assertEqual("FileNotFoundError", debug.call_args.kwargs["context"]["error_type"])
 
 
 class TestFilterMultiselectEmptyItems(unittest.TestCase):
@@ -60,8 +63,10 @@ class TestFilterMultiselectEmptyItems(unittest.TestCase):
         self.assertEqual([], result)
 
     def test_returns_none_when_tty_unavailable(self):
-        result = filter_multiselect(["a", "b"], tty_path="/nonexistent/tty")
+        with patch("bot_bottle.cli.tui.debug") as debug:
+            result = filter_multiselect(["a", "b"], tty_path="/nonexistent/tty")
         self.assertIsNone(result)
+        self.assertEqual("FileNotFoundError", debug.call_args.kwargs["context"]["error_type"])
 
 
 class TestMultiselectLoopReordering(unittest.TestCase):
diff --git a/tests/unit/test_egress_multitenant.py b/tests/unit/test_egress_multitenant.py
index 2aa5c869..1ab4dbd2 100644
--- a/tests/unit/test_egress_multitenant.py
+++ b/tests/unit/test_egress_multitenant.py
@@ -3,15 +3,16 @@
 from __future__ import annotations
 
 import unittest
+from unittest.mock import patch
 
-from bot_bottle.gateway.egress.addon_core import (
+from bot_bottle.gateway.egress.context import (
     DENY_RESOLVER_ERROR,
     DENY_UNATTRIBUTED,
     DENY_UNPARSEABLE,
-    decide,
     resolve_client_config,
     resolve_client_context,
 )
+from bot_bottle.gateway.egress.matching import decide
 from bot_bottle.gateway.policy_resolver import PolicyResolveError
 
 
@@ -44,7 +45,13 @@ class TestResolveClientConfig(unittest.TestCase):
 
     def test_resolver_error_denies_all(self) -> None:
         # Orchestrator unreachable/errored must never widen egress.
-        self.assertEqual((), resolve_client_config(_FakeResolver(raises=True), "10.243.0.1").routes)
+        with patch("bot_bottle.gateway.egress.context.debug") as debug:
+            config = resolve_client_config(_FakeResolver(raises=True), "10.243.0.1")
+        self.assertEqual((), config.routes)
+        self.assertEqual(
+            "PolicyResolveError", debug.call_args.kwargs["context"]["error_type"],
+        )
+        self.assertNotIn("orchestrator down", repr(debug.call_args))
 
     def test_unparseable_policy_denies_all(self) -> None:
         cfg = resolve_client_config(_FakeResolver(result="routes: notalist\n"), "10.243.0.1")
diff --git a/tests/unit/test_orchestrator_client.py b/tests/unit/test_orchestrator_client.py
index aa04a3e4..5ee3a84c 100644
--- a/tests/unit/test_orchestrator_client.py
+++ b/tests/unit/test_orchestrator_client.py
@@ -12,7 +12,9 @@ from bot_bottle.orchestrator.client import (
     OrchestratorClient,
     OrchestratorClientError,
     RegisteredBottle,
+    BackendProbeFailure,
     _host_auth_token,
+    _probe_failure,
 )
 
 _URLOPEN = "bot_bottle.orchestrator.client.urllib.request.urlopen"
@@ -33,6 +35,15 @@ class TestHostAuthToken(unittest.TestCase):
             self.assertEqual("", _host_auth_token())
 
 
+class TestBackendProbeFailure(unittest.TestCase):
+    def test_records_safe_typed_diagnostic(self) -> None:
+        with patch("bot_bottle.orchestrator.client.debug") as debug:
+            result = _probe_failure("firecracker", RuntimeError("secret detail"))
+        self.assertEqual(BackendProbeFailure("firecracker", "RuntimeError"), result)
+        rendered = repr(debug.call_args)
+        self.assertNotIn("secret detail", rendered)
+
+
 def _resp(status: int, payload: object) -> MagicMock:
     m = MagicMock()
     inner = m.__enter__.return_value
diff --git a/tests/unit/test_orchestrator_server.py b/tests/unit/test_orchestrator_server.py
index a43aa312..e2ecadb4 100644
--- a/tests/unit/test_orchestrator_server.py
+++ b/tests/unit/test_orchestrator_server.py
@@ -7,6 +7,7 @@ server tests), plus one real-socket round-trip to prove the handler wiring.
 from __future__ import annotations
 
 import base64
+import io
 import json
 import secrets
 import sqlite3
@@ -17,7 +18,7 @@ import urllib.error
 import urllib.request
 from contextlib import closing
 from pathlib import Path
-from unittest.mock import patch
+from unittest.mock import MagicMock, patch
 
 from bot_bottle.orchestrator_auth import ROLE_CLI, ROLE_GATEWAY, mint
 from bot_bottle.orchestrator.broker import StubBroker
@@ -283,6 +284,25 @@ class TestServerRoundTrip(unittest.TestCase):
         ))
         self.assertEqual(reg["bottle_id"], attr["bottle_id"])
 
+    def test_internal_failure_is_contextual_but_redacted(self) -> None:
+        orch = MagicMock()
+        orch.registry.all.side_effect = RuntimeError("SENSITIVE request value")
+        with patch("sys.stderr", io.StringIO()) as stderr:
+            server = make_server(orch, "127.0.0.1", 0)
+            self.addCleanup(server.server_close)
+            thread = threading.Thread(target=server.serve_forever, daemon=True)
+            thread.start()
+            self.addCleanup(server.shutdown)
+            host, port = server.server_address[0], server.server_address[1]
+            with self.assertRaises(urllib.error.HTTPError) as raised:
+                urllib.request.urlopen(f"http://{host}:{port}/bottles", timeout=5)
+            payload = json.loads(raised.exception.read())
+            output = stderr.getvalue()
+        self.assertEqual({"error": "internal error"}, payload)
+        self.assertIn("GET /bottles", output)
+        self.assertIn("RuntimeError", output)
+        self.assertNotIn("SENSITIVE", output)
+
 
 class TestOrchestratorAuth(unittest.TestCase):
     """Role-scoped control-plane tokens (issue #400 / #469 review): every route