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,
@@ -502,7 +521,7 @@ describe("AI SDK conversion utilities", () => {
 			})
 		})
 
-		it("emits the complete tool-call chunk after streaming input chunks", () => {
+		it("emits complete tool-input-available after streaming input chunks", () => {
 			const seenStreamingToolCallIds = new Set<string>()
 			const chunks = [
 				...processAiSdkStreamPart(
@@ -516,7 +535,7 @@ describe("AI SDK conversion utilities", () => {
 				...processAiSdkStreamPart({ type: "tool-input-end" as const, id: "call_1" }, seenStreamingToolCallIds),
 				...processAiSdkStreamPart(
 					{
-						type: "tool-call" as const,
+						type: "tool-input-available" as const,
 						toolCallId: "call_1",
 						toolName: "attempt_completion",
 						input: { result: "done" },
@@ -534,6 +553,78 @@ describe("AI SDK conversion utilities", () => {
 				},
 			])
 			expect(seenStreamingToolCallIds.has("call_1")).toBe(false)
+			expect(seenStreamingToolCallIds.has("completed:call_1")).toBe(true)
+		})
+
+		it("ignores duplicate tool-call chunks after complete tool-input-available chunks", () => {
+			const seenStreamingToolCallIds = new Set<string>()
+			const chunks = [
+				...processAiSdkStreamPart(
+					{
+						type: "tool-input-available" as const,
+						toolCallId: "call_1",
+						toolName: "attempt_completion",
+						input: { result: "done" },
+					},
+					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"}',
+				},
+			])
+			expect(seenStreamingToolCallIds.has("completed: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", () => {

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 +202,14 @@ 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
+}
+
+function hasToolInput(part: Pick<ToolInputPart, "input">) {
+	return part.input !== undefined && !isEmptyObject(part.input)
+}
+
 type ToolInputPart = {
 	id?: string
 	toolCallId?: string
@@ -215,6 +223,10 @@ function getToolCallId(part: ToolInputPart) {
 	return part.toolCallId ?? part.id ?? ""
 }
 
+function completedToolCallMarker(toolCallId: string) {
+	return `completed:${toolCallId}`
+}
+
 /**
  * Process a single AI SDK stream part and yield the appropriate ApiStreamChunk(s).
  * This generator handles all TextStreamPart types and converts them to the
@@ -249,6 +261,12 @@ export function* processAiSdkStreamPart(
 			break
 
 		case "tool-input-available":
+			if (seenStreamingToolCallIds?.has(getToolCallId(part)) && !hasToolInput(part)) {
+				break
+			}
+
+			seenStreamingToolCallIds?.delete(getToolCallId(part))
+			seenStreamingToolCallIds?.add(completedToolCallMarker(getToolCallId(part)))
 			yield {
 				type: "tool_call",
 				id: getToolCallId(part),
@@ -258,6 +276,11 @@ export function* processAiSdkStreamPart(
 			break
 
 		case "tool-call":
+			if (seenStreamingToolCallIds?.has(completedToolCallMarker(part.toolCallId))) {
+				seenStreamingToolCallIds.delete(completedToolCallMarker(part.toolCallId))
+				break
+			}
+
 			seenStreamingToolCallIds?.delete(part.toolCallId)
 			// Complete tool call - emit for compatibility
 			yield {