fix: replace silent exception swallowing with debug logging across tools

Add logger.debug() calls to 27 bare 'except: pass' blocks across 7 core
files, giving visibility into errors that were previously silently
swallowed. This makes it much easier to diagnose user-reported issues
from debug logs.

Files changed:
- tools/terminal_tool.py: 5 catches (stat, termios, fd close, cleanup)
- tools/delegate_tool.py: 7 catches + added logger (spinner, callbacks)
- tools/browser_tool.py: 5 catches (screenshot/recording cleanup, daemon kill)
- tools/code_execution_tool.py: 2 remaining catches (socket, server close)
- gateway/session.py: 2 catches (platform enum parse, temp file cleanup)
- agent/display.py: 2 catches + added logger (JSON parse in failure detect)
- agent/prompt_builder.py: 1 catch (skill description read)

Deliberately kept bare pass for:
- ImportError checks for optional dependencies (terminal_tool.py)
- SystemExit/KeyboardInterrupt handlers
- Spinner _write catch (would spam on every frame when stdout closed)
- process_registry PID-alive check (canonical os.kill(pid,0) pattern)

Extends the pattern from PR #686 (@aydnOktay).

agent/display.py

@@ -5,6 +5,7 @@ Used by AIAgent._execute_tool_calls for CLI feedback.
 """
 
 import json
+import logging
 import os
 import sys
 import threading
@@ -14,6 +15,8 @@ import time
 _RED = "\033[31m"
 _RESET = "\033[0m"
 
+logger = logging.getLogger(__name__)
+
 
 # =========================================================================
 # Skin-aware helpers (lazy import to avoid circular deps)
@@ -362,7 +365,7 @@ def _detect_tool_failure(tool_name: str, result: str | None) -> tuple[bool, str]
             if exit_code is not None and exit_code != 0:
                 return True, f" [exit {exit_code}]"
         except (json.JSONDecodeError, TypeError, AttributeError):
-            pass
+            logger.debug("Could not parse terminal result as JSON for exit code check")
         return False, ""
 
     # Memory-specific: distinguish "full" from real errors
@@ -372,7 +375,7 @@ def _detect_tool_failure(tool_name: str, result: str | None) -> tuple[bool, str]
             if data.get("success") is False and "exceed the limit" in data.get("error", ""):
                 return True, " [full]"
         except (json.JSONDecodeError, TypeError, AttributeError):
-            pass
+            logger.debug("Could not parse memory result as JSON for capacity check")
 
     # Generic heuristic for non-terminal tools
     lower = result[:500].lower()

agent/prompt_builder.py

@@ -159,8 +159,8 @@ def _read_skill_description(skill_file: Path, max_chars: int = 60) -> str:
             if len(desc) > max_chars:
                 desc = desc[:max_chars - 3] + "..."
             return desc
-    except Exception:
-        pass
+    except Exception as e:
+        logger.debug("Failed to read skill description from %s: %s", skill_file, e)
     return ""
 
 

gateway/session.py

@@ -272,8 +272,8 @@ class SessionEntry:
         if data.get("platform"):
             try:
                 platform = Platform(data["platform"])
-            except ValueError:
-                pass
+            except ValueError as e:
+                logger.debug("Unknown platform value %r: %s", data["platform"], e)
         
         return cls(
             session_key=data["session_key"],
@@ -370,8 +370,8 @@ class SessionStore:
         except BaseException:
             try:
                 os.unlink(tmp_path)
-            except OSError:
-                pass
+            except OSError as e:
+                logger.debug("Could not remove temp file %s: %s", tmp_path, e)
             raise
     
     def _generate_session_key(self, source: SessionSource) -> str:

tools/browser_tool.py

@@ -1615,10 +1615,10 @@ def _cleanup_old_screenshots(screenshots_dir, max_age_hours=24):
             try:
                 if f.stat().st_mtime < cutoff:
                     f.unlink()
-            except Exception:
-                pass
-    except Exception:
-        pass  # Non-critical — don't fail the screenshot operation
+            except Exception as e:
+                logger.debug("Failed to clean old screenshot %s: %s", f, e)
+    except Exception as e:
+        logger.debug("Screenshot cleanup error (non-critical): %s", e)
 
 
 def _cleanup_old_recordings(max_age_hours=72):
@@ -1634,10 +1634,10 @@ def _cleanup_old_recordings(max_age_hours=72):
             try:
                 if f.stat().st_mtime < cutoff:
                     f.unlink()
-            except Exception:
-                pass
-    except Exception:
-        pass
+            except Exception as e:
+                logger.debug("Failed to clean old recording %s: %s", f, e)
+    except Exception as e:
+        logger.debug("Recording cleanup error (non-critical): %s", e)
 
 
 # ============================================================================
@@ -1749,7 +1749,7 @@ def cleanup_browser(task_id: Optional[str] = None) -> None:
                         os.kill(daemon_pid, signal.SIGTERM)
                         logger.debug("Killed daemon pid %s for %s", daemon_pid, session_name)
                     except (ProcessLookupError, ValueError, PermissionError, OSError):
-                        pass
+                        logger.debug("Could not kill daemon pid for %s (already dead or inaccessible)", session_name)
                 shutil.rmtree(socket_dir, ignore_errors=True)
         
         logger.debug("Removed task %s from active sessions", task_id)

tools/code_execution_tool.py

@@ -335,8 +335,8 @@ def _rpc_server_loop(
         if conn:
             try:
                 conn.close()
-            except OSError:
-                pass
+            except OSError as e:
+                logger.debug("RPC conn close error: %s", e)
 
 
 # ---------------------------------------------------------------------------
@@ -550,8 +550,8 @@ def execute_code(
         # Cleanup temp dir and socket
         try:
             server_sock.close()
-        except Exception:
-            pass
+        except Exception as e:
+            logger.debug("Server socket close error: %s", e)
         try:
             import shutil
             shutil.rmtree(tmpdir, ignore_errors=True)

tools/delegate_tool.py

@@ -20,6 +20,7 @@ import contextlib
 import io
 import json
 import logging
+logger = logging.getLogger(__name__)
 import os
 import sys
 import time
@@ -107,8 +108,8 @@ def _build_child_progress_callback(task_index: int, parent_agent, task_count: in
                 short = (preview[:55] + "...") if preview and len(preview) > 55 else (preview or "")
                 try:
                     spinner.print_above(f" {prefix}├─ 💭 \"{short}\"")
-                except Exception:
-                    pass
+                except Exception as e:
+                    logger.debug("Spinner print_above failed: %s", e)
             # Don't relay thinking to gateway (too noisy for chat)
             return
 
@@ -129,8 +130,8 @@ def _build_child_progress_callback(task_index: int, parent_agent, task_count: in
                 line += f"  \"{short}\""
             try:
                 spinner.print_above(line)
-            except Exception:
-                pass
+            except Exception as e:
+                logger.debug("Spinner print_above failed: %s", e)
 
         if parent_cb:
             _batch.append(tool_name)
@@ -138,8 +139,8 @@ def _build_child_progress_callback(task_index: int, parent_agent, task_count: in
                 summary = ", ".join(_batch)
                 try:
                     parent_cb("subagent_progress", f"🔀 {prefix}{summary}")
-                except Exception:
-                    pass
+                except Exception as e:
+                    logger.debug("Parent callback failed: %s", e)
                 _batch.clear()
 
     def _flush():
@@ -148,8 +149,8 @@ def _build_child_progress_callback(task_index: int, parent_agent, task_count: in
             summary = ", ".join(_batch)
             try:
                 parent_cb("subagent_progress", f"🔀 {prefix}{summary}")
-            except Exception:
-                pass
+            except Exception as e:
+                logger.debug("Parent callback flush failed: %s", e)
             _batch.clear()
 
     _callback._flush = _flush
@@ -241,8 +242,8 @@ def _run_single_child(
         if child_progress_cb and hasattr(child_progress_cb, '_flush'):
             try:
                 child_progress_cb._flush()
-            except Exception:
-                pass
+            except Exception as e:
+                logger.debug("Progress callback flush failed: %s", e)
 
         duration = round(time.monotonic() - child_start, 2)
 
@@ -287,8 +288,8 @@ def _run_single_child(
         if hasattr(parent_agent, '_active_children'):
             try:
                 parent_agent._active_children.remove(child)
-            except (ValueError, UnboundLocalError):
-                pass
+            except (ValueError, UnboundLocalError) as e:
+                logger.debug("Could not remove child from active_children: %s", e)
 
 
 def delegate_task(
@@ -425,8 +426,8 @@ def delegate_task(
                 if spinner_ref and remaining > 0:
                     try:
                         spinner_ref.update_text(f"🔀 {remaining} task{'s' if remaining != 1 else ''} remaining")
-                    except Exception:
-                        pass
+                    except Exception as e:
+                        logger.debug("Spinner update_text failed: %s", e)
 
         # Restore stdout/stderr in case redirect_stdout race left them as devnull
         sys.stdout = _saved_stdout

tools/terminal_tool.py

@@ -84,8 +84,8 @@ def _check_disk_usage_warning():
                 if f.is_file():
                     try:
                         total_bytes += f.stat().st_size
-                    except OSError:
-                        pass
+                    except OSError as e:
+                        logger.debug("Could not stat file %s: %s", f, e)
         
         total_gb = total_bytes / (1024 ** 3)
         
@@ -231,13 +231,13 @@ def _prompt_for_sudo_password(timeout_seconds: int = 45) -> str:
                 try:
                     import termios as _termios
                     _termios.tcsetattr(tty_fd, _termios.TCSAFLUSH, old_attrs)
-                except Exception:
-                    pass
+                except Exception as e:
+                    logger.debug("Failed to restore terminal attributes: %s", e)
             if tty_fd is not None:
                 try:
                     os.close(tty_fd)
-                except Exception:
-                    pass
+                except Exception as e:
+                    logger.debug("Failed to close tty fd: %s", e)
             result["done"] = True
     
     try:
@@ -690,8 +690,8 @@ def get_active_environments_info() -> Dict[str, Any]:
             try:
                 size = sum(f.stat().st_size for f in Path(path).rglob('*') if f.is_file())
                 total_size += size
-            except OSError:
-                pass
+            except OSError as e:
+                logger.debug("Could not stat path %s: %s", path, e)
     
     info["total_disk_usage_mb"] = round(total_size / (1024 * 1024), 2)
     return info
@@ -718,8 +718,8 @@ def cleanup_all_environments():
         try:
             shutil.rmtree(path, ignore_errors=True)
             logger.info("Removed orphaned: %s", path)
-        except OSError:
-            pass
+        except OSError as e:
+            logger.debug("Failed to remove orphaned path %s: %s", path, e)
     
     if cleaned > 0:
         logger.info("Cleaned %d environments", cleaned)