Add support for Cerebras ai model api

- It does not support strict mode for json schema, tool use
- It likes text content to be plain string, not nested in a dictionary
- Verified to work with gpt oss models on cerebras

src/khoj/processor/conversation/openai/gpt.py

@@ -8,6 +8,7 @@ from khoj.processor.conversation.openai.utils import (
     clean_response_schema,
     completion_with_backoff,
     get_structured_output_support,
+    is_cerebras_api,
     responses_chat_completion_with_backoff,
     responses_completion_with_backoff,
     supports_responses_api,
@@ -40,8 +41,11 @@ def send_message_to_model(
 
     model_kwargs: Dict[str, Any] = {}
     json_support = get_structured_output_support(model, api_base_url)
+    strict = not is_cerebras_api(api_base_url)
     if tools and json_support == StructuredOutputSupport.TOOL:
-        model_kwargs["tools"] = to_openai_tools(tools, use_responses_api=supports_responses_api(model, api_base_url))
+        model_kwargs["tools"] = to_openai_tools(
+            tools, use_responses_api=supports_responses_api(model, api_base_url), strict=strict
+        )
     elif response_schema and json_support >= StructuredOutputSupport.SCHEMA:
         # Drop unsupported fields from schema passed to OpenAI APi
         cleaned_response_schema = clean_response_schema(response_schema)
@@ -49,7 +53,7 @@ def send_message_to_model(
             model_kwargs["text"] = {
                 "format": {
                     "type": "json_schema",
-                    "strict": True,
+                    "strict": strict,
                     "name": response_schema.__name__,
                     "schema": cleaned_response_schema,
                 }
@@ -60,7 +64,7 @@ def send_message_to_model(
                 "json_schema": {
                     "schema": cleaned_response_schema,
                     "name": response_schema.__name__,
-                    "strict": True,
+                    "strict": strict,
                 },
             }
     elif response_type == "json_object" and json_support == StructuredOutputSupport.OBJECT:

src/khoj/processor/conversation/openai/utils.py

@@ -795,7 +795,7 @@ def format_message_for_api(raw_messages: List[ChatMessage], model_name: str, api
                 if (
                     part.get("type") == "text"
                     and message.role == "assistant"
-                    and api_base_url.startswith("https://api.deepinfra.com/v1")
+                    and (api_base_url.startswith("https://api.deepinfra.com/v1") or is_cerebras_api(api_base_url))
                 ):
                     assistant_texts += [part["text"]]
                     message.content.pop(idx)
@@ -876,6 +876,13 @@ def is_twitter_reasoning_model(model_name: str, api_base_url: str = None) -> boo
     )
 
 
+def is_cerebras_api(api_base_url: str = None) -> bool:
+    """
+    Check if the model is served over the Cerebras API
+    """
+    return api_base_url is not None and api_base_url.startswith("https://api.cerebras.ai/v1")
+
+
 def is_groq_api(api_base_url: str = None) -> bool:
     """
     Check if the model is served over the Groq API
@@ -1212,7 +1219,7 @@ def add_qwen_no_think_tag(formatted_messages: List[dict]) -> None:
                         break
 
 
-def to_openai_tools(tools: List[ToolDefinition], use_responses_api: bool) -> List[Dict] | None:
+def to_openai_tools(tools: List[ToolDefinition], use_responses_api: bool, strict: bool) -> List[Dict] | None:
     "Transform tool definitions from standard format to OpenAI format."
     if use_responses_api:
         openai_tools = [
@@ -1221,7 +1228,7 @@ def to_openai_tools(tools: List[ToolDefinition], use_responses_api: bool) -> Lis
                 "name": tool.name,
                 "description": tool.description,
                 "parameters": clean_response_schema(tool.schema),
-                "strict": True,
+                "strict": strict,
             }
             for tool in tools
         ]
@@ -1233,7 +1240,7 @@ def to_openai_tools(tools: List[ToolDefinition], use_responses_api: bool) -> Lis
                     "name": tool.name,
                     "description": tool.description,
                     "parameters": clean_response_schema(tool.schema),
-                    "strict": True,
+                    "strict": strict,
                 },
             }
             for tool in tools