feat(openai): added support for o1 reasoning models (#1618)

* fix(openai): systemRoleSupported model configuration for openai endpoints

* feat(openai): max_completion_tokens now used over max_tokens for chat_completeions endpoint.

* fix: lint

* feat(docs): add o1 example

* fix: make parameter default to false and fix type checks

---------

Co-authored-by: Nathan Sarrazin <[email protected]>

docs/source/configuration/models/providers/openai.md

@@ -53,6 +53,25 @@ MODELS=`[{
 }]`
 ```
 
+We also support models in the `o1` family. You need to add a few more options ot the config: Here is an example for `o1-mini`:
+
+```ini
+MODELS=`[
+  {
+      "name": "o1-mini",
+      "description": "ChatGPT o1-mini",
+      "systemRoleSupported": false,
+      "parameters": {
+        "max_new_tokens": 2048,
+      },
+      "endpoints" : [{
+        "type": "openai",
+        "useCompletionTokens": true,
+      }]
+  }
+]
+```
+
 You may also consume any model provider that provides compatible OpenAI API endpoint. For example, you may self-host [Portkey](https://github.com/Portkey-AI/gateway) gateway and experiment with Claude or GPTs offered by Azure OpenAI. Example for Claude from Anthropic:
 
 ```ini

src/lib/server/endpoints/openai/endpointOai.ts

@@ -111,6 +111,8 @@ export const endpointOAIParametersSchema = z.object({
 			}),
 		})
 		.default({}),
+	/* enable use of max_completion_tokens in place of max_tokens */
+	useCompletionTokens: z.boolean().default(false),
 });
 
 export async function endpointOai(
@@ -125,6 +127,7 @@ export async function endpointOai(
 		defaultQuery,
 		multimodal,
 		extraBody,
+		useCompletionTokens,
 	} = endpointOAIParametersSchema.parse(input);
 
 	let OpenAI;
@@ -199,6 +202,14 @@ export async function endpointOai(
 				messagesOpenAI[0].content = preprompt ?? "";
 			}
 
+			// if system role is not supported, convert first message to a user message.
+			if (!model.systemRoleSupported && messagesOpenAI?.[0]?.role === "system") {
+				messagesOpenAI[0] = {
+					...messagesOpenAI[0],
+					role: "user",
+				};
+			}
+
 			if (toolResults && toolResults.length > 0) {
 				const toolCallRequests: OpenAI.Chat.Completions.ChatCompletionAssistantMessageParam = {
 					role: "assistant",
@@ -241,7 +252,9 @@ export async function endpointOai(
 				model: model.id ?? model.name,
 				messages: messagesOpenAI,
 				stream: true,
-				max_tokens: parameters?.max_new_tokens,
+				...(useCompletionTokens
+					? { max_completion_tokens: parameters?.max_new_tokens }
+					: { max_tokens: parameters?.max_new_tokens }),
 				stop: parameters?.stop,
 				temperature: parameters?.temperature,
 				top_p: parameters?.top_p,