ai: OpenAI and Codex forced tool calls (#6588)

* feat(ai): support forced OpenAI Codex tool calls

* feat(ai): support OpenAI Responses tool choice

packages/ai/src/api/openai-codex-responses.ts

@@ -85,6 +85,7 @@ export interface OpenAICodexResponsesOptions extends StreamOptions {
 	reasoningSummary?: "auto" | "concise" | "detailed" | "off" | "on" | null;
 	serviceTier?: ResponseCreateParamsStreaming["service_tier"];
 	textVerbosity?: "low" | "medium" | "high";
+	toolChoice?: "auto" | "none" | "required";
 }
 
 type CodexResponseStatus = "completed" | "incomplete" | "failed" | "cancelled" | "queued" | "in_progress";
@@ -97,7 +98,7 @@ interface RequestBody {
 	previous_response_id?: string;
 	input?: ResponseInput;
 	tools?: OpenAITool[];
-	tool_choice?: "auto";
+	tool_choice?: OpenAICodexResponsesOptions["toolChoice"];
 	parallel_tool_calls?: boolean;
 	temperature?: number;
 	reasoning?: { effort?: string; summary?: string };
@@ -497,7 +498,7 @@ function buildRequestBody(
 		text: { verbosity: options?.textVerbosity || "low" },
 		include: ["reasoning.encrypted_content"],
 		prompt_cache_key: clampOpenAIPromptCacheKey(options?.sessionId),
-		tool_choice: "auto",
+		tool_choice: options?.toolChoice ?? "auto",
 		parallel_tool_calls: true,
 	};
 

packages/ai/src/api/openai-responses.ts

@@ -83,6 +83,7 @@ export interface OpenAIResponsesOptions extends StreamOptions {
 	reasoningEffort?: "minimal" | "low" | "medium" | "high" | "xhigh" | "max";
 	reasoningSummary?: "auto" | "detailed" | "concise" | null;
 	serviceTier?: ResponseCreateParamsStreaming["service_tier"];
+	toolChoice?: ResponseCreateParamsStreaming["tool_choice"];
 }
 
 /**
@@ -254,6 +255,10 @@ function buildParams(model: Model<"openai-responses">, context: Context, options
 		params.tools = convertResponsesTools(toolPlacement.immediate);
 	}
 
+	if (options?.toolChoice !== undefined) {
+		params.tool_choice = options.toolChoice;
+	}
+
 	if (model.reasoning) {
 		if (options?.reasoningEffort || options?.reasoningSummary) {
 			const effort = options?.reasoningEffort