feat(agent): improve tiktoken initialization and device registration

- Configure tiktoken cache directory to isolate encoding files
- Add logging and timing for tiktoken initialization process
- Make Huawei CE and Ruijie Telnet device registration idempotent
- Add duplicate registration prevention with global flags
- Add logging for device type registration status
- Update .gitignore to exclude tiktoken cache files

.gitignore

@@ -72,3 +72,6 @@ venv
 .claude/
 !.claude/development.md  # Exception: allow development docs
 # PROJECT_CONTEXT.md  # Commented out: allow tracking project context
+
+# Tiktoken cache files
+gns3server/agent/gns3_copilot/cache/tiktoken/

gns3server/agent/gns3_copilot/agent/context_manager.py

@@ -43,10 +43,17 @@ Requirements:
 
 import json
 import logging
+import os
 import warnings
+from pathlib import Path
 from typing import Any
 from typing import Callable
 
+# Configure tiktoken cache directory (must be set before importing tiktoken)
+_cache_dir = Path(__file__).parent.parent / "cache" / "tiktoken"
+_cache_dir.mkdir(parents=True, exist_ok=True)
+os.environ["TIKTOKEN_CACHE_DIR"] = str(_cache_dir)
+
 import tiktoken
 from langchain_core.messages import BaseMessage
 from langchain_core.messages import SystemMessage
@@ -59,8 +66,14 @@ logger = logging.getLogger(__name__)
 # ============================================================================
 
 # Initialize tiktoken encoding (required dependency)
+import time
+logger.info("Initializing tiktoken encoding (cl100k_base)...")
+logger.info(f"Cache directory: {_cache_dir}")
+logger.info("This may take a moment on first run (downloading ~1.6MB encoding file from openaipublic.blob.core.windows.net)")
+start_time = time.time()
 _tiktoken_encoding = tiktoken.get_encoding("cl100k_base")
-logger.info("Using tiktoken (cl100k_base) for accurate token counting")
+elapsed = time.time() - start_time
+logger.info(f"✓ tiktoken encoding loaded successfully (took {elapsed:.2f}s)")
 
 # ============================================================================
 # Constants

gns3server/agent/gns3_copilot/utils/custom_netmiko/huawei_ce.py

@@ -79,6 +79,8 @@ import time
 
 from netmiko.huawei.huawei import HuaweiBase
 
+logger = logging.getLogger(__name__)
+
 
 class GNS3HuaweiTelnetCE(HuaweiBase):
     """
@@ -373,6 +375,8 @@ class GNS3HuaweiTelnetCE(HuaweiBase):
 
 
 # Register the custom device type with Netmiko
+_registered = False  # Flag to prevent duplicate registration
+
 def register_custom_device_type() -> None:
     """
     Register the custom GNS3HuaweiTelnetCE device type with Netmiko.
@@ -388,9 +392,18 @@ def register_custom_device_type() -> None:
     or running any Netmiko tasks. Call it explicitly at the appropriate
     time.
 
+    Note: This function is idempotent - multiple calls will only register once.
+
     Returns:
         None
     """
+    global _registered
+
+    # Prevent duplicate registration
+    if _registered:
+        logger.debug("Huawei CE device type already registered, skipping")
+        return
+
     # Use importlib to avoid namespace conflicts
     # Import the module using importlib to ensure we get the module,
     # not a function
@@ -423,6 +436,11 @@ def register_custom_device_type() -> None:
     sd.platforms_str = "\n" + "\n".join(sd.platforms_base)
     sd.telnet_platforms_str = "\n" + "\n".join(sd.telnet_platforms)
 
+    # Mark as registered
+    _registered = True
+
+    logger.info("Successfully registered Huawei CE device type with Netmiko")
+
 
 # Auto-register on import
 # This ensures the device type is available when the module is imported

gns3server/agent/gns3_copilot/utils/custom_netmiko/ruijie_telnet.py

@@ -46,6 +46,8 @@ import time
 
 from netmiko.ruijie.ruijie_os import RuijieOSBase
 
+logger = logging.getLogger(__name__)
+
 
 class RuijieTelnetEnhanced(RuijieOSBase):
     """
@@ -249,13 +251,24 @@ class RuijieTelnetEnhanced(RuijieOSBase):
 
 
 # Register the custom device type with Netmiko
+_registered = False  # Flag to prevent duplicate registration
+
 def register_custom_device_type() -> None:
     """
     Register the custom RuijieTelnetEnhanced device type with Netmiko.
 
     This function adds 'gns3_ruijie_telnet' to Netmiko's CLASS_MAPPER
     and updates the platforms lists.
+
+    Note: This function is idempotent - multiple calls will only register once.
     """
+    global _registered
+
+    # Prevent duplicate registration
+    if _registered:
+        logger.debug("Ruijie Telnet device type already registered, skipping")
+        return
+
     sd = importlib.import_module("netmiko.ssh_dispatcher")
 
     # Register in both mappers
@@ -271,6 +284,11 @@ def register_custom_device_type() -> None:
     sd.platforms_str = "\n" + "\n".join(sd.platforms_base)
     sd.telnet_platforms_str = "\n" + "\n".join(sd.telnet_platforms)
 
+    # Mark as registered
+    _registered = True
+
+    logger.info("Successfully registered Ruijie Telnet device type with Netmiko")
+
 
 # Auto-register on import
 try:

gns3server/agent/gns3_copilot/utils/custom_netmiko/vpcs_telnet.py

@@ -368,6 +368,8 @@ class VPCSTelnet(BaseConnection):
 
 
 # Register the custom device type with Netmiko
+_registered = False  # Flag to prevent duplicate registration
+
 def register_custom_device_type() -> None:
     """
     Register the custom VPCS Telnet device type with Netmiko.
@@ -377,7 +379,16 @@ def register_custom_device_type() -> None:
 
     IMPORTANT: This function should be called BEFORE using the VPCS device
     type with Netmiko.
+
+    Note: This function is idempotent - multiple calls will only register once.
     """
+    global _registered
+
+    # Prevent duplicate registration
+    if _registered:
+        logger.debug("VPCS Telnet device type already registered, skipping")
+        return
+
     # Use importlib to avoid namespace conflicts
     sd = importlib.import_module("netmiko.ssh_dispatcher")
 
@@ -408,6 +419,9 @@ def register_custom_device_type() -> None:
     sd.platforms_str = "\n" + "\n".join(sd.platforms_base)
     sd.telnet_platforms_str = "\n" + "\n".join(sd.telnet_platforms)
 
+    # Mark as registered
+    _registered = True
+
     logger.info("Successfully registered VPCS Telnet device type with Netmiko")