> ## 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.

# Language detection

> Prepare the language-detection tool and its early-conversation policy while keeping ASR, response language, and live switching separate.

Language detection describes a requested decision to change the conversation language. Prepare the supported languages and corresponding messages before adding a switching policy.

<Note>
  This is system-tool authoring guidance. It does not establish live language detection or switching. The dashboard's separate Language and ASR selectors are unsaved previews, and voice publication remains unavailable.
</Note>

## Review the policy

The tool is stored at `conversation_config.agent.prompt.built_in_tools.language_detection`. Its `params` contains:

| Field | Authored meaning |
| - | - |
| `system_tool_type` | Must be `language_detection`. |
| `only_at_conversation_start` | Boolean; defaults to `false`. |

When `only_at_conversation_start` is enabled, the requested policy is: if no language switch occurs during the first two user turns, keep the current language afterward. If a switch occurs during those turns, later switching remains permitted. This describes intended behavior, not a verified runtime result.

## Prepare the configuration

<Steps>
  <Step title="Choose the language set">
    Follow [Language](/agents-platform/configure/voice-and-language/language) to prepare the base response language, recognition settings, and any language presets. A detection tool does not add language support to a model or voice.
  </Step>

  <Step title="Open the tool settings">
    On the agent's **Tools > System tools** panel, enable **Language Detection** and open its settings. Review the **Only at conversation start** switch and the description of when detection is appropriate.
  </Step>

  <Step title="Save and inspect">
    Select **Save** to update the working copy. Preserve the reviewed tool in a complete [server draft](/agents-platform/deploy/versioning) for API read-back. Check its policy separately from `conversation_config.agent.language` and `response_language_policy`.
  </Step>

  <Step title="Prepare ambiguous examples">
    Include a greeting in one language followed by a full request in another, a quoted foreign phrase, and a user explicitly requesting a language change. Record the intended response for later testing.
  </Step>
</Steps>

## Frequently asked questions

<AccordionGroup>
  <Accordion title="Is this the same as ASR recognition mode?" id="faq-language-tool-asr">
    No. Input recognition belongs to ASR configuration. This tool describes a requested conversation-language action; the base response policy and language presets are also separate settings.
  </Accordion>

  <Accordion title="Does enabling it translate my prompt?" id="faq-language-tool-translation">
    No automatic prompt translation is established by the tool. Review the authored wording and language-specific messages yourself.
  </Accordion>
</AccordionGroup>


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