Add helpful ImportError messages for optional dependencies

When optional dependencies are missing, raise ImportError with
installation
instructions pointing to the relevant extras group (e.g. `[messaging]`,
`[cli]`, `[mcp]`, etc.) instead of letting the import fail silently.

tools/mcp_tool.py

@@ -1501,7 +1501,13 @@ def _snapshot_child_pids() -> set:
         pass
 
     # Fallback: psutil
-    import psutil
+    try:
+        import psutil
+    except ImportError:
+        raise ImportError(
+            "psutil is required for MCP child process tracking. "
+            "Install with: pip install hermes-agent[mcp]"
+        ) from None
     try:
         return {c.pid for c in psutil.Process(my_pid).children()}
     except psutil.Error:

tools/neutts_synth.py

@@ -71,7 +71,13 @@ def main():
 
     ref_text = ref_text_path.read_text(encoding="utf-8").strip()
 
-    from neutts import NeuTTS
+    try:
+        from neutts import NeuTTS
+    except ImportError:
+        raise ImportError(
+            "neutts is required for local TTS synthesis. "
+            "Install with: pip install hermes-agent[tts-local]"
+        ) from None
 
     tts = NeuTTS(
         backbone_repo=args.model,
@@ -86,7 +92,13 @@ def main():
     out_path = Path(args.out)
     out_path.parent.mkdir(parents=True, exist_ok=True)
 
-    import soundfile as sf
+    try:
+        import soundfile as sf
+    except ImportError:
+        raise ImportError(
+            "soundfile is required for audio output. "
+            "Install with: pip install hermes-agent[tts-local]"
+        ) from None
     sf.write(str(out_path), wav, 24000)
 
     print(f"OK: {out_path}", file=sys.stderr)

tools/process_registry.py

@@ -335,10 +335,17 @@ class ProcessRegistry:
         )
 
         if use_pty:
-            if _IS_WINDOWS:
-                from winpty import PtyProcess as _PtyProcessCls
-            else:
-                from ptyprocess import PtyProcess as _PtyProcessCls
+            try:
+                if _IS_WINDOWS:
+                    from winpty import PtyProcess as _PtyProcessCls
+                else:
+                    from ptyprocess import PtyProcess as _PtyProcessCls
+            except ImportError:
+                pkg = "winpty" if _IS_WINDOWS else "ptyprocess"
+                raise ImportError(
+                    f"{pkg} is required for PTY mode. "
+                    "Install with: pip install hermes-agent[pty]"
+                ) from None
             try:
                 user_shell = _find_shell()
                 pty_env = _sanitize_subprocess_env(os.environ, env_vars)

tools/vision_tools.py

@@ -318,7 +318,13 @@ def _resize_image_for_vision(image_path: Path, mime_type: Optional[str] = None,
     else:
         data_url = None  # defer full encode; try Pillow resize first
 
-    from PIL import Image
+    try:
+        from PIL import Image
+    except ImportError:
+        raise ImportError(
+            "Pillow is required for image resizing. "
+            "Install with: pip install hermes-agent[cli]"
+        ) from None
     import io as _io
 
     logger.info("Image file is %.1f MB (estimated base64 %.1f MB, limit %.1f MB), auto-resizing...",