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

# LLM cascading

> Configure managed model fallback policy, backup order, and timeout, then inspect the saved configuration.

Cascading configuration defines the requested backup models when a primary model cannot provide an acceptable response in time. Saving that policy is separate from demonstrating failover in a live conversation.

## Select the policy

The dashboard's **Backup LLM configuration** provides Default, Custom, and Disabled choices. These map to `conversation_config.agent.prompt.backup_llm_config`:

| Preference | Configuration intent |
| - | - |
| `default` | Resolve the platform-managed backup order from the workspace-selectable catalog. |
| `override` | Supply an explicit ordered list of supported catalog model IDs. |
| `disabled` | Request no backup model. |

`cascade_timeout_seconds` defaults to 4 seconds and accepts 2–15 seconds. Review model compatibility, latency requirements, and provider costs before changing the order or timeout.

## Review and save

Use [platform-managed backup discovery](/api-reference/agents-platform/get-the-platform-managed-llm-backup-order) and the [LLM catalog](/api-reference/agents-platform/list-available-llms). Preserve the selected primary model and unrelated prompt settings. For supported managed text-only publication, the primary and backups must resolve against the same catalog release.

Read the saved branch or draft back. Empty or incompatible custom backup selections, or an unavailable default policy, can prevent publication. Custom LLM selection requires disabled backups and cannot currently be published.

## Frequently asked questions

<AccordionGroup>
  <Accordion title="Does the timeout guarantee a response within that duration?" id="faq-cascade-timeout">No. It records fallback intent. End-to-end latency and actual failover require a released runtime and measured tests.</Accordion>
  <Accordion title="Can I use custom endpoints as managed backups?" id="faq-cascade-custom-model">The reviewed custom-LLM selection requires disabled backups. Do not substitute custom endpoint definitions for supported catalog IDs.</Accordion>
</AccordionGroup>


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