---
title: "The API gateway"
description: "The API gateway: the 2 calls this system serves, each a route of the API and a tool of the MCP server, at contract 0476e35e6e275db5."
section: systems
address: /systems/10-the-api-gateway
contract: 0476e35e6e275db5
---

# The API gateway

The API gateway: the 2 calls this system serves, each a route of the API and a tool of the MCP server, at contract 0476e35e6e275db5.

[figure: The API gateway: 2 calls of the contract, by family.]

# The API gateway

The 2 calls below are the whole of this system on the wire: each is one route of the API and one tool of the MCP server, with one typed input, one card as its answer and one refusal shape. Every answer carries its foot: what was read, the population and the control.

## The calls



| tool | route | takes | gives |
|---|---|---|---|
| [si.read.failed_calls](/reference/tools/si-read-failed_calls) | [POST /v1/read/failed_calls](/reference/read/failed_calls) | a tenant | every signed call that did not land, with why, and a way to send it again |
| [si.act.webhook](/reference/tools/si-act-webhook) | [POST /v1/act/webhook](/reference/act/webhook) | the address, what to be told about, and a secret to sign with | the row |



## The bars this system enforces

Every bar is a row of the parameter register: an administrator changes it, and the platform reads it by name at the place of enforcement the row records.

| parameter | family | dimension | enforced at |
|---|---|---|---|
| the service level of a read, for each verb | machinery | a time for each verb | the API gateway, measured at the first build stage and then fixed |
| the bound on tries of a signed call | machinery | a count | the durable work that makes the call |
| how long signed calls that failed are kept | machinery | a time | the store of failed calls |
| the MCP adapter's longest wait for the app server | machinery | a time | the adapter's socket, which opens again on its own after the app server restarts and tries for this long before it refuses a call (stipulated at ninety seconds until the setting row is written) |