> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ringup.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Introduction

> Five REST tools for platforms that own their whole conversation flow.

Most integrations never touch these endpoints directly: the pre-built payment step calls
them for you. They are documented for platforms that own their entire conversation loop and
want to register Ringup's tools on their own LLM.

## Base URL

```text theme={null}
https://ringup.dev/api/tools
```

All five tools are `POST` endpoints with JSON bodies.

## Identity rides headers, not arguments

The caller and the merchant are resolved server-side from three headers your platform
templates in at call time. The model never types either identity, so neither can be
mistyped, hallucinated, or prompt-injected. See
[Caller and merchant identity](/concepts/identity).

| Header              | Value                                                    | Purpose                                             |
| ------------------- | -------------------------------------------------------- | --------------------------------------------------- |
| `X-Caller-Number`   | The caller's number, E.164 (platform caller-ID variable) | Who is calling                                      |
| `X-Ringup-Merchant` | The dialed number, E.164, or your explicit merchant id   | Which business they called                          |
| `X-Call-Id`         | The platform's call id                                   | Charge idempotency: retries can never double-charge |

<Warning>
  Web and dashboard test calls carry no real caller ID, so the caller-ID template resolves to
  nothing. Pin a test caller explicitly for those; real inbound phone calls resolve
  everything natively.
</Warning>

## Idempotency

Charges are deduplicated server-side against the call id and amount. A platform retry, a
model retry, or a duplicated tool call returns the original payment result instead of
charging twice. This is a server guarantee, not a client convention.

## Test mode

The shared sandbox answers these endpoints for every account with ready-made fixtures
(merchants with different policies, a caller with a saved Visa). See
[Testing](/concepts/testing).