# Versions and compatibility.

Read the current contract and keep client assumptions explicit.

Updated: 2026-09-21.
## REST

Customer operations use `/v1`. The compact [agent OpenAPI document](/openapi.json) is the entry point for public and authenticated tool operations. The API’s [complete contract](https://api.agentik.cc/openapi.json) remains available for existing integrations. Operation IDs identify documented operations; the tool catalog remains a separate, changing resource.

## MCP

Clients negotiate their MCP protocol version during initialisation. Inspect the tools advertised by the connected server: a public connection and an authenticated connection expose different capabilities. Read the advertised input and output schemas instead of assuming a fixed catalog.

## Changes

Review the [changelog](/changelog). Tool availability, provider schemas and pricing can change; inspect the selected tool immediately before execution. Existing compatibility names in the API do not represent a second product. No retirement date or support-duration guarantee is implied by this page.

---

[HTML page](/docs/versions) · [Agent index](/llms.txt)