feat: add gemini tools (#120)

src/tools/impl/WriteTodosGemini.ts

@@ -0,0 +1,60 @@
+/**
+ * Gemini CLI write_todos tool - adapter for Letta Code's todo_write
+ * Uses Gemini's exact schema and description but adapts the params
+ */
+
+interface WriteTodosGeminiArgs {
+  todos: Array<{
+    description: string;
+    status: "pending" | "in_progress" | "completed" | "cancelled";
+  }>;
+}
+
+export async function write_todos(
+  args: WriteTodosGeminiArgs,
+): Promise<{ message: string; todos: typeof args.todos }> {
+  // Gemini uses "description" field, Letta Code uses "content" field
+  // Convert to Letta format and validate
+  if (!Array.isArray(args.todos)) {
+    throw new Error("todos must be an array");
+  }
+
+  for (const todo of args.todos) {
+    if (!todo.description || typeof todo.description !== "string") {
+      throw new Error("Each todo must have a description string");
+    }
+    if (
+      !todo.status ||
+      !["pending", "in_progress", "completed", "cancelled"].includes(
+        todo.status,
+      )
+    ) {
+      throw new Error(
+        "Each todo must have a valid status (pending, in_progress, completed, or cancelled)",
+      );
+    }
+  }
+
+  // Validate only one in_progress
+  const inProgressCount = args.todos.filter(
+    (t) => t.status === "in_progress",
+  ).length;
+  if (inProgressCount > 1) {
+    throw new Error("Only one task can be 'in_progress' at a time.");
+  }
+
+  const todoListString = args.todos
+    .map((todo, index) => `${index + 1}. [${todo.status}] ${todo.description}`)
+    .join("\n");
+
+  const message =
+    args.todos.length > 0
+      ? `Successfully updated the todo list. The current list is now:\n${todoListString}`
+      : "Successfully cleared the todo list.";
+
+  // Return with both message and todos for UI rendering
+  return {
+    message,
+    todos: args.todos,
+  };
+}