protect() is the shortest TypeScript path for executable tool objects. It wraps execute, func, or invoke, calls Veto Cloud before the tool runs, and throws before execution when a call is denied or needs approval.

Set VETO_API_KEY, or pass apiKey directly:

export VETO_API_KEY=veto_...

import { protect } from "veto-sdk";

const tools = await protect([
  {
    name: "issue_refund",
    description: "Issue a customer refund",
    execute: async ({ amount_usd }: { amount_usd: number }) => {
      return { refunded: amount_usd };
    },
  },
]);

Explicit Client

Use Veto.init() when you want to reuse one client for Guard, Charter, tool registration, and approvals:

import { Veto } from "veto-sdk";

const veto = await Veto.init({
  baseUrl: process.env.VETO_API_URL ?? "https://api.veto.so",
  apiKey: process.env.VETO_API_KEY!,
});

const tools = veto.wrap([
  {
    name: "prod_db_query",
    execute: async ({ sql }: { sql: string }) => runQuery(sql),
  },
]);

Denials

Denied and approval-required calls throw ToolCallDeniedError before your tool executes.

import { ToolCallDeniedError } from "veto-sdk";

try {
  await tools[0].execute({ amount_usd: 900 });
} catch (error) {
  if (error instanceof ToolCallDeniedError) {
    console.error(error.toolName, error.decision, error.message);
  }
}

Approval Waiting

By default, require_approval does not execute the tool. To wait for an approval decision, opt in:

const tools = await protect(existingTools, {
  apiKey: process.env.VETO_API_KEY!,
  approvalMode: "wait",
  approvalTimeoutMs: 10 * 60 * 1000,
});

Notes

protect() accepts one executable tool or an array.
Supported executable methods are execute, func, and invoke.
Schema-only tool definitions are not enough for execution-time enforcement. Use provider adapters for schemas, or use the Vercel AI SDK middleware for model-level interception.
Missing API keys fail explicitly. The SDK does not silently fall back to unguarded allow-all execution.

Protect Tools

Explicit Client

Denials

Approval Waiting

Notes

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