chore(vendor): import pi 1.3.0

Imported as a linear vendor commit so forge rebases do not replay the upstream root tree.

git-subtree-dir: third_party/pi

git-subtree-split: 71023aec1546d6d677a65669c5665c0927ce0dd0

third_party/pi/packages/ai/test/validation.test.ts

@@ -1,7 +1,7 @@
 import { Type } from "typebox";
 import { Compile } from "typebox/compile";
 import { describe, expect, it } from "vitest";
-import type { Tool, ToolCall } from "../src/types.ts";
+import type { JsonValue, Tool, ToolCall } from "../src/types.ts";
 import { validateToolArguments } from "../src/utils/validation.ts";
 
 function createToolCallWithPlainSchema(
@@ -27,7 +27,7 @@ function createToolCallWithPlainSchema(
 		type: "toolCall",
 		id: "tool-1",
 		name: "echo",
-		arguments: { value },
+		arguments: { value: value as JsonValue },
 	};
 
 	return { tool, toolCall };
@@ -207,4 +207,23 @@ describe("validateToolArguments", () => {
 			expect(() => validateToolArguments(tool, toolCall)).toThrow("Validation failed");
 		}
 	});
+	// #10897
+	it("reports malformed arguments JSON instead of validating empty arguments", () => {
+		const tool: Tool = {
+			name: "echo",
+			description: "Echo tool",
+			parameters: Type.Object({ value: Type.Optional(Type.String()) }),
+		};
+		const toolCall: ToolCall = {
+			type: "toolCall",
+			id: "tool-1",
+			name: "echo",
+			arguments: {},
+			argumentsError: "Unexpected token",
+		};
+
+		expect(() => validateToolArguments(tool, toolCall)).toThrow(
+			'Invalid arguments for tool "echo": Unexpected token',
+		);
+	});
 });