> ## Documentation Index > Fetch the complete documentation index at: https://docs.getmillwork.dev/llms.txt > Use this file to discover all available pages before exploring further. # Terminology > Look up the one Millwork word for each part of a run, what it means, and what it is not. Millwork uses one word for each part of a run across the docs, the API examples, and the dashboard. This page defines each word, names the API field where it differs, and says what the word does not mean. A **run** is one task you send to Millwork; the API calls it an `execution`. A live run is submitted to call a model. Every live run has a **platform fee**, charged when Millwork accepts the run; read [Model access and billing](/concepts/access) for the full rule. ## What you save and what Millwork picks | Term | Meaning | What it is not | | -------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------- | | **Arm** | A saved option Millwork may run your task on: a model, an agent endpoint, or a skill. The docs say saved model; the API calls every saved option an `arm`. | Saving an arm does not force Millwork to pick it. An arm is not the route chosen for a run. | | **Catalog model** | A model your organization can save now, listed by `GET /v1/model-catalog`. | A catalog entry is not a promise that the provider has capacity at this moment. | | **Route** | The path recorded for a run: which saved model was chosen and any fallback options. | A route is not a second name for an arm. A test run makes no model call. Provider-reported model details are separate and may be absent. | | **Output check** | A check applied to the run's output. The API calls it a verifier (`verifier_id`). If you do not name one, a basic check confirms only that output is present. | An output check does not decide whether the answer is right for your product. | | **Provider account** | Your account with the company, cloud, or gateway that serves a model. Its connection to Millwork decides who bills the model usage. | Millwork never returns or reveals your provider key. | ## A run and its records | Term | Meaning | What it is not | | --------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------ | | **Run** | One task you send to Millwork and follow to a final status. The API calls it an `execution`, with an `execution_id`. | A run is not proof that a model answered. A test run is also a run. | | **Test run** | A run that exercises your integration without calling a model. The API calls it Echo (`mode: "echo"`). It has no platform fee and no model cost, and it counts toward your quota like any run. | A test run is not proof that a model can answer your task. It returns no model output. | | **Request key** | The value you send in the `Idempotency-Key` header. A retry with the same key and the same body returns the same run instead of starting a second one. | A request key is not a run id. A retry with the same key and a different body is refused; read [Errors and retries](/guides/errors-and-retries). | | **Result** | The model output of a completed live run, from `GET /v1/executions/{executionId}/result`. It can expire. | Test, failed, cancelled, and expired runs have no result. | | **Receipt** | The record of a run's outcome, route, model usage, checks, and any follow-up action. Runs on catalog models also record model and provider details when available. | A receipt never contains the prompt or the output. Its model-usage totals exclude the platform fee. | ## Money and accounts | Term | Meaning | What it is not | | ---------------- | ------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------- | | **Platform fee** | Millwork's charge for a live run, charged when Millwork accepts the run. | The platform fee is not model usage. Cancelling a run does not return it. Millwork returns it only when it fails a run before any model attempt starts. | | **Organization** | Your company or team in Millwork: its members, API keys, saved models, and runs. The CLI and API call an organization a tenant. | An organization is not a person. API keys belong to the organization, not to a member. | Use [How Solver works](/overview/how-solver-works) for the full sequence. Use [Results and receipts](/concepts/results-and-receipts) for storage and expiry guidance.