Add support for npm packages and .env files to custom tools

[cte]

You can now have a custom tool that looks like:

import { fileURLToPath } from "url";
import path from "path";

import dotenv from "dotenv";
import { type ModelMessage, streamText } from "ai";
import { parametersSchema as z, defineCustomTool } from "@roo-code/types";

const dotenvPath = path.join(
  path.dirname(fileURLToPath(import.meta.url)),
  ".env"
);

dotenv.config({ path: dotenvPath });

const parameters = z.object({
  text: z.string().describe("The text to generate a fortune for"),
});

type Parameters = z.infer<typeof parameters>;

export default defineCustomTool({
  name: "fortune",
  description: "Generate a fortune for a given text",
  parameters,
  async execute({ text }: Parameters) {
    if (!process.env.AI_GATEWAY_API_KEY) {
      throw new Error(`AI_GATEWAY_API_KEY is not set in ${dotenvPath}`);
    }

    const messages: ModelMessage[] = [
      {
        role: "system",
        content: `You are a fortune teller. You will be given a question and you will need to generate a fortune for it.`,
      },
      { role: "user", content: text },
    ];

    const result = streamText({
      model: "anthropic/claude-sonnet-4.5",
      messages,
    });

    let content = "";

    for await (const delta of result.textStream) {
      content += delta;
      process.stdout.write(delta);
    }

    return content;
  },
});

Where your sensitive env vars (like AI_GATEWAY_API_KEY) are stored in a .env file in the same directory as the custom tool.

[roomote]

Rooviewer   See task on Roo Cloud

Review completed. Found 1 issue worth noting.

• .env files from different tools may overwrite each other in the shared cache directory

_{Mention @roomote in a comment to request specific changes to this pull request or fix all unresolved issues.}

[roomote]

When multiple tools have .env files, they will overwrite each other in the shared cache directory. If tools A and B each have different .env files with different secrets, loading tool B will overwrite tool A's .env, causing tool A to potentially read incorrect environment variables. Consider using tool-specific subdirectories (e.g., path.join(this.cacheDir, hash)) or documenting that users should use distinct env var names across tools.

_{Fix it with Roo Code or mention @roomote and request a fix.}

[cte]

This is a really good point. I'll follow up with a fix for this.

[cte]

Addresses part of #10323