Ignore streaming AI SDK tool availability

Author: Alex-yang00

src/api/transform/__tests__/ai-sdk.spec.ts

@@ -484,6 +484,25 @@ describe("AI SDK conversion utilities", () => {
 			})
 		})
 
+		it("uses args when tool-call input is an empty object", () => {
+			const part = {
+				type: "tool-call" as const,
+				toolCallId: "call_1",
+				toolName: "attempt_completion",
+				input: {},
+				args: { result: "done" },
+			}
+			const chunks = [...processAiSdkStreamPart(part as any)]
+
+			expect(chunks).toHaveLength(1)
+			expect(chunks[0]).toEqual({
+				type: "tool_call",
+				id: "call_1",
+				name: "attempt_completion",
+				arguments: '{"result":"done"}',
+			})
+		})
+
 		it("processes complete tool-call chunks with arguments", () => {
 			const part = {
 				type: "tool-call" as const,
@@ -536,6 +555,43 @@ describe("AI SDK conversion utilities", () => {
 			expect(seenStreamingToolCallIds.has("call_1")).toBe(false)
 		})
 
+		it("ignores tool-input-available for calls that are still streaming input", () => {
+			const seenStreamingToolCallIds = new Set<string>()
+			const chunks = [
+				...processAiSdkStreamPart(
+					{ type: "tool-input-start" as const, id: "call_1", toolName: "attempt_completion" },
+					seenStreamingToolCallIds,
+				),
+				...processAiSdkStreamPart(
+					{
+						type: "tool-input-available" as const,
+						toolCallId: "call_1",
+						toolName: "attempt_completion",
+						input: {},
+					},
+					seenStreamingToolCallIds,
+				),
+				...processAiSdkStreamPart(
+					{
+						type: "tool-call" as const,
+						toolCallId: "call_1",
+						toolName: "attempt_completion",
+						input: { result: "done" },
+					},
+					seenStreamingToolCallIds,
+				),
+			]
+
+			expect(chunks).toEqual([
+				{
+					type: "tool_call",
+					id: "call_1",
+					name: "attempt_completion",
+					arguments: '{"result":"done"}',
+				},
+			])
+		})
+
 		it("processes source chunks with URL", () => {
 			const part = {
 				type: "source" as const,

src/api/transform/ai-sdk.ts

@@ -191,7 +191,7 @@ type ExtendedStreamPart =
 
 function stringifyToolInput(part: Extract<TextStreamPart<any>, { type: "tool-call" }>) {
 	const input =
-		"input" in part && part.input !== undefined
+		"input" in part && part.input !== undefined && !isEmptyObject(part.input)
 			? part.input
 			: "args" in part
 				? (part as { args: unknown }).args
@@ -202,6 +202,10 @@ function stringifyToolInput(part: Extract<TextStreamPart<any>, { type: "tool-cal
 	return typeof input === "string" ? input : JSON.stringify(input)
 }
 
+function isEmptyObject(value: unknown) {
+	return typeof value === "object" && value !== null && !Array.isArray(value) && Object.keys(value).length === 0
+}
+
 type ToolInputPart = {
 	id?: string
 	toolCallId?: string
@@ -249,6 +253,10 @@ export function* processAiSdkStreamPart(
 			break
 
 		case "tool-input-available":
+			if (seenStreamingToolCallIds?.has(getToolCallId(part))) {
+				break
+			}
+
 			yield {
 				type: "tool_call",
 				id: getToolCallId(part),