fix(coding-agent/tools): removed the enforced minimum length for the

- Removed the enforced minimum length for the `items` array in the tool schema to prevent unnecessary validation errors on operations that ignore the field.
- Added tests to verify schema acceptance of empty `items` arrays and confirmed that runtime errors are still correctly thrown for empty inputs during specific operations like `append`.

packages/coding-agent/src/tools/todo.ts

@@ -57,7 +57,10 @@ const todoSchema = type({
 	"list?": InitListEntry.array().describe("phased task list (init)"),
 	"task?": type("string").describe("task content"),
 	"phase?": type("string").describe("phase name"),
-	"items?": type("string").describe("task content").array().atLeastLength(1).describe("tasks to append"),
+	// No `atLeastLength(1)` here: `items` is only meaningful for `init`/`append`,
+	// and both enforce non-empty with op-specific errors. A stray `items: []` on
+	// an op that ignores it (e.g. `view`) must not be a hard schema rejection.
+	"items?": type("string").describe("task content").array().describe("tasks to append"),
 }).describe("apply a single todo operation");
 
 type TodoParams = TodoSchema;

packages/coding-agent/test/tools/todo.test.ts

@@ -15,6 +15,7 @@ import {
 	todoToolRenderer,
 } from "@oh-my-pi/pi-coding-agent/tools";
 import type { Component } from "@oh-my-pi/pi-tui";
+import { type } from "arktype";
 
 function createSession(initialPhases: TodoPhase[] = []): ToolSession {
 	let phases = initialPhases;
@@ -284,6 +285,29 @@ describe("TodoTool lenient init shapes", () => {
 	});
 });
 
+describe("TodoTool empty items tolerance", () => {
+	// Regression: a stray `items: []` on an op that ignores items (here `view`)
+	// must not be a hard schema rejection. The top-level `items` array dropped
+	// its `atLeastLength(1)` so callers don't get "items must be tasks to append"
+	// for an irrelevant empty array; length is enforced per-op at runtime.
+	it("accepts op:view with an empty items array at the schema boundary", () => {
+		const schema = new TodoTool(createSession()).parameters;
+		expect(schema({ op: "view", items: [] }) instanceof type.errors).toBe(false);
+	});
+
+	it("defers empty append items to an op-specific runtime error", async () => {
+		const tool = new TodoTool(createSession());
+		await tool.execute("call-1", { op: "init", list: [{ phase: "Work", items: ["First"] }] });
+
+		const result = await tool.execute("call-2", { op: "append", phase: "Work", items: [] });
+
+		expect(result.isError).toBe(true);
+		const summary = result.content.find(part => part.type === "text");
+		if (summary?.type !== "text") throw new Error("Expected text summary");
+		expect(summary.text).toContain("Missing items for append operation");
+	});
+});
+
 describe("selectStickyTodoWindow", () => {
 	const makeTasks = (statuses: TodoStatus[]): TodoItem[] =>
 		statuses.map((status, i) => ({ content: `task-${i + 1}`, status }));