feat(llm-deepseek): configure max token defaults

packages/llm/llm-deepseek/src/serialize.ts

@@ -137,9 +137,14 @@ export function serializeMessages(messages: Message[]): WireMessage[] {
  * provider defaults apply.
  * @param options - the harness request (model, history, system, tools, sampling).
  * @param defaults - adapter-level thinking defaults; undefined fields put nothing on the wire.
+ * @param defaultMaxTokens - adapter output default used only when the request omits a cap.
  * @returns the chat-completions request body.
  */
-export function serializeRequest(options: GenerateOptions, defaults: RequestDefaults = {}): WireRequest {
+export function serializeRequest(
+  options: GenerateOptions,
+  defaults: RequestDefaults = {},
+  defaultMaxTokens?: number,
+): WireRequest {
   const messages: WireMessage[] = []
   if (options.system !== undefined) {
     messages.push({ role: 'system', content: options.system })
@@ -157,6 +162,7 @@ export function serializeRequest(options: GenerateOptions, defaults: RequestDefa
   // A short title budget must produce visible text; conversation and
   // compaction calls continue to inherit the adapter's thinking defaults.
   const resolvedThinking = resolveThinking(options, defaults)
+  const maxTokens = options.maxTokens ?? defaultMaxTokens
 
   return {
     model: options.model,
@@ -169,7 +175,7 @@ export function serializeRequest(options: GenerateOptions, defaults: RequestDefa
       : {},
     ...tools !== undefined && tools.length > 0 ? { tools } : {},
     ...options.temperature !== undefined ? { temperature: options.temperature } : {},
-    ...options.maxTokens !== undefined ? { max_tokens: options.maxTokens } : {},
+    ...maxTokens === undefined ? {} : { max_tokens: maxTokens },
     ...options.stop !== undefined ? { stop: options.stop } : {},
   }
 }