# aityx docs

> A decision API for AI applications. Ask questions about your data and get typed answers—including calculated amounts and dates.

## Docs

- [Introduction](https://aityx.ai/docs): Get choices, calculated amounts and dates from one decision API.
- [Answer a cancellation request](https://aityx.ai/docs/quickstart): Run the homepage refund example with matching facts, then interpret a customer message.

## Concepts

- [System One and System Two](https://aityx.ai/docs/concepts/system-one-and-two): Execute matching facts with System One; interpret input or create models with System Two.
- [State](https://aityx.ai/docs/concepts/state): Supply one state for the case; choose matching-fact execution or AI interpretation.
- [Answer types and questions](https://aityx.ai/docs/concepts/questions): Native answers are inferred from decisions. Questions are used for Jev execution or model authoring.
- [Models](https://aityx.ai/docs/concepts/models): Send the native JSON definition with each case; answer names and types come from its decisions.
- [Receipts](https://aityx.ai/docs/concepts/receipts): Trace an answer to its facts, calculations and sources; keep the evidence with the case.
- [Determinism and confidence](https://aityx.ai/docs/concepts/determinism-and-confidence): Separate repeatable calculations from uncertainty in interpreted facts.

## Guides

- [Decisions with calculated answers](https://aityx.ai/docs/guides/use-cases): The six console examples: three native decisions and three Jev + aityx decisions.
- [Call it from JavaScript and Python](https://aityx.ai/docs/guides/call-from-code): Execute matching facts or interpret a message using the same native model.
- [Run an invoice decision](https://aityx.ai/docs/guides/invoice-example): Use a prepared invoice model, check the date cutoff, and inspect the amount and receipt. No generation on your first call.
- [Build a model from a prompt or a document](https://aityx.ai/docs/guides/build-from-a-prompt): Use System Two to create a native definition, then execute it with each case.
- [Define a model by hand](https://aityx.ai/docs/guides/define-by-hand): Write native JSON and execute it without a model-generation call.
- [Compare revised rules](https://aityx.ai/docs/guides/revise-and-replay): Keep both definitions and compare the same inputs before changing your application.
- [The console](https://aityx.ai/docs/guides/console): Build a decision, supply state, execute, and copy the current request as curl.

## Resources

- [Model format](https://aityx.ai/docs/resources/model-format): The compact JSON a model is written in. Types, inputs, decisions, tables, functions and the expression language.
- [Errors](https://aityx.ai/docs/resources/errors): Handle schema errors, missing evidence and completed Jev with a model failure.
- [Pricing and limits](https://aityx.ai/docs/resources/pricing-and-limits): Two rates, three routes, and one charge per completed request.

## Using Jev with aityx

- [Using Jev with aityx](https://aityx.ai/docs/coming-from-jev): Run Jev questions and native calculations in one System One request.

## Reference

- [aityx API](https://aityx.ai/docs/reference)

### Operations

- [Create or revise an aityx model](https://aityx.ai/docs/reference/operations/author-decision)
- [Execute matching facts or Jev questions](https://aityx.ai/docs/reference/operations/execute-decision)
- [Interpret supplied input, then execute a model](https://aityx.ai/docs/reference/operations/interpret-and-execute)

## Agent skills

- [aityx-docs](https://aityx.ai/docs/.well-known/agent-skills/aityx-docs/SKILL.md): Read the aityx docs instead of answering from memory. A decision API for AI applications. Ask questions about your data and get typed answers—including calculated amounts and dates. Use when a task involves aityx docs: how it works, how to set it up or configure it, or its API.

## Agent resources

- [llms-full.txt](https://aityx.ai/docs/llms-full.txt): The full Markdown of every page in one file.
- [Page Markdown](https://aityx.ai/docs/index.md): Append `.md` to any page URL to fetch that page as raw Markdown.
- [JSON API](https://aityx.ai/docs/api/docs/pages.json): Page index of the JSON docs API; each entry links the page's JSON and Markdown forms. Described by the OpenAPI document at https://aityx.ai/docs/openapi.json.
- [Agent skills](https://aityx.ai/docs/.well-known/agent-skills/index.json): Agent Skills discovery index of the skills this site publishes.
- [API catalog](https://aityx.ai/docs/.well-known/api-catalog): RFC 9727 linkset of the APIs documented here.
- [AI catalog](https://aityx.ai/docs/.well-known/ai-catalog.json): ARD manifest of the agent-facing resources on this site (MCP server, skills, APIs).
- [agent-readability.json](https://aityx.ai/docs/agent-readability.json): Manifest of every agent-facing artifact on this site.
- [Sitemap](https://aityx.ai/docs/sitemap.xml): Every indexable page URL with its last-modified date.