Watchpost for Claude Desktop

A safety net for the things Claude wants to buy.

Watchpost adds a local MCP tool that Claude Desktop can call before a purchase. It runs three checks and returns approve, review, or block. This is a cooperating-agent guardrail: it does not intercept a payment if Claude or another tool skips the Watchpost call.

Get WatchpostHow it works
One command
npx @watchpost/mcp install
The CLI opens a browser to confirm your account, writes the connection token into Claude Desktop's claude_desktop_config.json, and asks you to restart the app. You're done in under five minutes.
Real verdicts

What it looks like with Claude Desktop.

Approved14:02
amazon.comUSB-C cable, 6ft, braided
$15.99

Trusted merchant, listing is clean, well within your daily cap. Claude proceeds without asking you.

Review14:02
open-ai-credits.exampleAPI credits — $50, auto-renew
$50.00

Listing has recurring-billing language but Claude marked it one-off. You get a push to confirm.

Blocked13:58
too-good-deals.ioPremium subscription, best deal
$199.00

Trust score below your minimum and the listing has hidden Unicode pointed at the AI. Watchpost stops it without bothering you.

Setup with Claude Desktop

Five minutes, no surprises.

  1. 01
    Sign up

    Email and a password. No credit card to start. You'll land on a dashboard with sensible defaults already set.

  2. 02
    Set your rules

    Caps per purchase, day, and month. An ask-me threshold for anything above your usual range. Categories you don't buy.

  3. 03
    Run the installer

    On your Mac, Windows, or Linux machine: npx @watchpost/mcp install. The CLI confirms your account in the browser, writes the MCP entry into Claude Desktop's config, and asks you to restart Claude.

  4. 04
    Test the check

    Ask Claude to run Watchpost on a sample purchase before paying. The MCP tool returns approve, review, or block, and its instructions tell Claude to honor the result.

Frequently asked

Specific to Claude Desktop.

Does Claude have to be on a paid Anthropic plan?
Watchpost works wherever your current Claude Desktop plan and build allow local MCP servers. Anthropic can change product availability, so confirm MCP support in Claude Desktop's settings before installing.
What if Claude is using a tool like a browser or Stripe Link to actually pay?
Watchpost runs before the payment step. As long as Claude calls watchpost_check_purchase before it executes the payment tool, you're protected. The MCP install guides Claude to use Watchpost first.
Can I see what Claude tried to buy before I noticed the push?
Yes. The dashboard at watchpost.systems/transactions lists every verdict, with reasoning and outcome. Search by merchant, filter by decision, drill into any one.
What happens to the listing data Claude sends Watchpost?
The purchase details are stored with the verdict so you can review your transaction history and audit what the agent submitted. Listing text may be sent to Anthropic for the manipulation scan. See the privacy policy for the current processor and retention details.

Switch it on for Claude Desktop.

Free for 10 verdicts a month. Upgrade only when your agent gets busy.

Get WatchpostSee pricing