# Webhook Tool Filler Messages Now Available for Telnyx AI Assistants

> Source: <https://telnyx.com/release-notes/webhook-tool-filler-messages>
> Published: 2026-07-06 00:00:00+00:00

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AI Assistants can now speak scripted utterances at the start of a webhook tool call and during long-running requests. Callers stay engaged while the assistant waits on an external API, database lookup, or third-party model, instead of sitting in silence.

Silence is where voice AI calls die. A webhook tool call that takes 8 to 12 seconds for a database lookup or third-party API leaves the caller staring at dead air, and on a phone call that reads as broken, not loading. Most voice platforms either go silent and lose the caller, or ask the LLM to improvise filler, which rambles, drifts off-brand, and can't be tuned.

This lets you script the wait-state UX the same way you script the conversation flow. "Let me look that up for you" at the start, "still working on this" at 5 seconds, "almost there" at 15 seconds. Deterministic, tiered, and per-tool. The same control you have over the conversation now extends to the gaps the conversation depends on.

Each filler message has a `type`

of `request_start`

(spoken immediately when the tool call begins) or `request_response_delayed`

(spoken after `timing_ms`

milliseconds if the response has not yet arrived). The `timing_ms`

field accepts 100 to 120000 ms and is only required for delayed messages. Once the response arrives, any remaining delayed messages are skipped.

```
{
  "filler_messages": [
    { "type": "request_start", "content": "Let me look that up for you." },
    { "type": "request_response_delayed", "content": "Still working on this.", "timing_ms": 5000 },
    { "type": "request_response_delayed", "content": "Almost there.", "timing_ms": 15000 }
  ]
}
```

**Learn more** in the [AI Assistants docs](https://developers.telnyx.com/docs/inference/ai-assistants) or the [Telnyx docs](https://developers.telnyx.com).