pi/packages/coding-agent/src/core/tools/write.ts

import type { AgentTool } from "@mariozechner/pi-agent-core";
import { Type } from "@sinclair/typebox";
import { mkdir as fsMkdir, writeFile as fsWriteFile } from "fs/promises";
import { dirname } from "path";
import { resolveToCwd } from "./path-utils.js";

const writeSchema = Type.Object({
	path: Type.String({ description: "Path to the file to write (relative or absolute)" }),
	content: Type.String({ description: "Content to write to the file" }),
});

/**
 * Pluggable operations for the write tool.
 * Override these to delegate file writing to remote systems (e.g., SSH).
 */
export interface WriteOperations {
	/** Write content to a file */
	writeFile: (absolutePath: string, content: string) => Promise<void>;
	/** Create directory (recursively) */
	mkdir: (dir: string) => Promise<void>;
}

const defaultWriteOperations: WriteOperations = {
	writeFile: (path, content) => fsWriteFile(path, content, "utf-8"),
	mkdir: (dir) => fsMkdir(dir, { recursive: true }).then(() => {}),
};

export interface WriteToolOptions {
	/** Custom operations for file writing. Default: local filesystem */
	operations?: WriteOperations;
}

export function createWriteTool(cwd: string, options?: WriteToolOptions): AgentTool<typeof writeSchema> {
	const ops = options?.operations ?? defaultWriteOperations;

	return {
		name: "write",
		label: "write",
		description:
			"Write content to a file. Creates the file if it doesn't exist, overwrites if it does. Automatically creates parent directories.",
		parameters: writeSchema,
		execute: async (
			_toolCallId: string,
			{ path, content }: { path: string; content: string },
			signal?: AbortSignal,
		) => {
			const absolutePath = resolveToCwd(path, cwd);
			const dir = dirname(absolutePath);

			return new Promise<{ content: Array<{ type: "text"; text: string }>; details: undefined }>(
				(resolve, reject) => {
					// Check if already aborted
					if (signal?.aborted) {
						reject(new Error("Operation aborted"));
						return;
					}

					let aborted = false;

					// Set up abort handler
					const onAbort = () => {
						aborted = true;
						reject(new Error("Operation aborted"));
					};

					if (signal) {
						signal.addEventListener("abort", onAbort, { once: true });
					}

					// Perform the write operation
					(async () => {
						try {
							// Create parent directories if needed
							await ops.mkdir(dir);

							// Check if aborted before writing
							if (aborted) {
								return;
							}

							// Write the file
							await ops.writeFile(absolutePath, content);

							// Check if aborted after writing
							if (aborted) {
								return;
							}

							// Clean up abort handler
							if (signal) {
								signal.removeEventListener("abort", onAbort);
							}

							resolve({
								content: [{ type: "text", text: `Successfully wrote ${content.length} bytes to ${path}` }],
								details: undefined,
							});
						} catch (error: any) {
							// Clean up abort handler
							if (signal) {
								signal.removeEventListener("abort", onAbort);
							}

							if (!aborted) {
								reject(error);
							}
						}
					})();
				},
			);
		},
	};
}

/** Default write tool using process.cwd() - for backwards compatibility */
export const writeTool = createWriteTool(process.cwd());