safe4

Tests an AI agent's purchase against the task it was given.

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What it can do

    What data it sees

    Do you need an account

    No: the server works without sign-in

    Tests an AI agent's purchase against the task it was given. Paid per call in USDC via x402.

    How to connect

    How to connect safe4 to Claude

    The server address to paste into Claude settings:

    https://api.safe4.ai/mcp/

    1. Open Claude (claude.ai or the desktop app).
    2. Go to Settings → Connectors.
    3. Click Add custom connector.
    4. Paste the server address copied below into Remote MCP server URL and click Add.
    5. In a chat, click + → Connectors and switch the new connector on.

    Custom connectors are available on Free, Pro, Max, Team and Enterprise plans (Free is limited to one). On Team and Enterprise an organization Owner adds the connector first under Organization settings → Connectors.

    Authorization

    After you click Add, a sign-in window for the service opens. Sign in with your own account and approve access. Claude never sees your password.

    How to connect safe4 to ChatGPT

    The server address to paste into ChatGPT settings:

    https://api.safe4.ai/mcp/

    1. Open ChatGPT in a browser (chatgpt.com). A Plus, Pro, Business, Enterprise or Edu plan is required.
    2. Turn on developer mode once: Settings → Apps → Advanced settings → Developer mode.
    3. Open Settings → Connectors and click Create.
    4. Fill in the form: Name (anything), Description (one line about what the service does), MCP server URL (copy it below).
    5. Under Authentication choose OAuth if the service requires sign-in, otherwise None. Click Create.
    6. In a new chat open + → Apps/Connectors and enable the connector.

    OpenAI has renamed this section before (Connectors → Apps/Plugins). If the label differs, search settings for "developer mode". On Business/Enterprise workspaces an admin must allow custom connectors first.

    Authorization

    On first use ChatGPT opens the service's sign-in window. Sign in and approve access.

    How to connect safe4 to Cursor

    The server address to paste into Cursor settings:

    https://api.safe4.ai/mcp/

    Fastest: click Open in Cursor below and confirm the prompt.

    Manually:

    1. In Cursor open Settings → Cursor Settings → MCP and click Add new global MCP server.
    2. Paste the JSON copied below into ~/.cursor/mcp.json (per project: .cursor/mcp.json in the repo root).
    3. Save the file. The server appears in the MCP list; authorize it there if asked.

    Authorization

    If the service needs sign-in, an authorize button appears next to the server in the MCP list.

    Server tool list (2)

    Raw names from tools/list. Only developers need these.

    safe4_pricePrice and accepted payment networks for one Safe4 decision. Free to call. Returns the same x402 terms the HTTP endpoint advertises, so an agent can see the cost before committing to a paid call.
    safe4_authorizeDecide whether a proposed agent payment should proceed. Settled per call in USDC over x402. Called without ``payment`` it returns the price list rather than a decision; call it again with the signed payload to receive one. The task and the two allow-lists are the principal's constraints, not the agent's: they are what the purchase is tested against, so an agent that writes its own ``task`` is grading its own homework. Safe4 records every field it was given in the audit entry and marks the task context as request-supplied, so a substituted constraint is visible afterwards. Args: task: The task the agent was given, as stated by its principal. purchase: What is being bought. purchase_purpose: Why this purchase serves the task. amount: Decimal amount as a string, for example "25.00". currency: Currency of the proposed payment, for example "USDC". counterparty: Who would receive the payment. service_category: Category of the thing being bought. allowed_service_categories: Categories the principal permits. allowed_counterparties: Optional payees the principal permits. When supplied, payment to anyone else is denied. task_id: Optional caller-side task identifier, echoed into the audit. payment: An x402 payment payload for this call. Omit to receive the price list instead of a decision.