docs: add context limit and strategy to LLM model configs API

- Add `context_limit` as required field for LLM model configurations
- Add `context_strategy` as optional field with three trimming strategies
- Update API documentation with detailed examples for GPT-4o and Claude 3.5 Sonnet
- Clarify that context limit is specified in K tokens (thousands of tokens)
- Update example payloads to reflect current model versions and new fields

gns3server/api/routes/controller/llm_model_configs.py

@@ -182,6 +182,9 @@ async def create_user_llm_model_config(
     Create a new LLM model configuration for a user.
 
     Required privilege: User.Modify
+
+    IMPORTANT: context_limit is REQUIRED. Unit is K tokens (e.g., 128 = 128K = 128,000 tokens).
+    Please check your model provider's documentation for the current context window size.
     """
 
     # Verify user exists
@@ -189,6 +192,14 @@ async def create_user_llm_model_config(
     if not user:
         raise ControllerNotFoundError(f"User '{user_id}' not found")
 
+    # Validate context_limit is provided
+    if not hasattr(config_create, 'context_limit') or config_create.context_limit is None:
+        raise ControllerBadRequestError(
+            "context_limit is required (unit: K tokens, e.g., 128 = 128K = 128,000 tokens). "
+            "Please check your model provider's documentation for the current context window size "
+            "and specify it in the configuration."
+        )
+
     try:
         # Extract config fields (excluding table-level fields)
         config_fields = config_create.model_dump(exclude={"name", "model_type", "is_default"})
@@ -493,6 +504,9 @@ async def create_group_llm_model_config(
     Create a new LLM model configuration for a user group.
 
     Required privilege: Group.Modify
+
+    IMPORTANT: context_limit is REQUIRED. Unit is K tokens (e.g., 128 = 128K = 128,000 tokens).
+    Please check your model provider's documentation for the current context window size.
     """
 
     # Verify group exists
@@ -500,6 +514,14 @@ async def create_group_llm_model_config(
     if not group:
         raise ControllerNotFoundError(f"User group '{group_id}' not found")
 
+    # Validate context_limit is provided
+    if not hasattr(config_create, 'context_limit') or config_create.context_limit is None:
+        raise ControllerBadRequestError(
+            "context_limit is required (unit: K tokens, e.g., 128 = 128K = 128,000 tokens). "
+            "Please check your model provider's documentation for the current context window size "
+            "and specify it in the configuration."
+        )
+
     try:
         # Extract config fields (excluding table-level fields)
         config_fields = config_create.model_dump(exclude={"name", "model_type", "is_default"})