Voice agent settings reference
Every ThunderPhone voice agent setting explained: tiers, voices, languages, acknowledgements, tools, speak order, voicemail, consent announcements, silence handling, testing, and deployment.
Open Voice Agents, select an agent, and use its Config tab to control how it sounds, reasons, starts calls, uses tools, handles silence and voicemail, and reaches callers. Changes autosave to a draft; production traffic does not change until you select Deploy.
This page is the complete dashboard reference. For field names and request examples, use the Agents API reference.
Prompt and identity
The agent name identifies it throughout the dashboard, reports, call history, and client portals. The prompt is the agent's operating script: persona, business facts, required questions, escalation policy, and call actions.
The prompt editor reports estimated tokens and flags common problems such as an empty prompt, unresolved template placeholders, a missing escalation path, or a very long prompt. The first 5,000 estimated tokens are included; longer prompts use block-based surcharge pricing.
Model tier
| Tier | Base price | Best fit |
|---|---|---|
| Spark | 2¢/min | Cost-sensitive, straightforward calls. |
| Bolt | 5¢/min | Fast responses and balanced everyday workflows. |
| Storm | 9¢/min | Complex instructions, audio understanding, and reasoning. |
Storm exposes two optional controls:
- Acknowledgement — None stays silent while preparing the full reply; Tick plays a soft waiting sound; Verbal speaks a brief acknowledgement and adds 2¢/min. Verbal text can be generated from the main prompt or supplied manually through the API.
- Extra intelligence — adds deeper reasoning for complex calls and 3¢/min.
The builder continuously shows the agent's all-in cost per minute, including the tier, voice/language path, prompt length, verbal acknowledgement, extra intelligence, and supervision.
Voice, background, and languages
Select a voice and play its sample before deploying. The picker only offers voices compatible with every selected language and marks premium combinations with their surcharge. Your custom voices appear in the same picker once ready. See Voice library and custom voices.
Background track can be:
- None — no ambient audio.
- Call center — a call-center ambience, with an in-dashboard preview.
Set one primary language, then any number of additional languages. The agent automatically detects when a caller switches to a selected language and responds in it. Some voice/language combinations add 3¢/min; see the generated Supported languages catalog.
Connected capabilities
The Config tab has four independently attachable capability sections:
| Section | Use it for |
|---|---|
| Connected apps | Approved operations in Google Calendar, Google Sheets, Slack, HubSpot, Salesforce, or Cal.com. |
| API connections | Your own HTTP endpoints, described as callable functions. |
| Knowledge | Files or web content the agent can search during a call. |
| MCP servers | Cached tools discovered from remote Model Context Protocol servers. |
An attachment is part of the draft and becomes available to production calls after deployment. Configure the resources first under Connections or Knowledge, then attach them to the agent.
Phone and web endpoints
Under Phone numbers, attach an existing number, provision a demo number, or import a number through a VoIP connection. A number can use different agents for inbound and outbound directions.
Under Web widgets, attach a widget so visitors can speak to the agent from a site. Widget availability can also be enabled or disabled as part of agent configuration.
Advanced call behavior
Expand Advanced at the bottom of Config for the following controls.
Supervision
When enabled, a second AI monitor checks each agent turn against the instructions and can intervene silently. Supervision adds 8¢/min and is not available on Bolt.
Connection tone
Play a short tone immediately after the call connects and before either party speaks.
Tool sound
Choose the sound made by the prompt-callable sound tool:
- None — the tool is not offered.
- Chime, Ding, or Beep — each can be previewed in the builder.
Who speaks first
Configure inbound and outbound calls separately:
- Inbound: agent speaks first, or caller speaks first.
- Outbound: agent speaks first, or callee speaks first.
This setting is useful for outbound dialers that must wait for a person or phone menu before beginning the script.
Voicemail handling
Choose what happens when an outbound call reaches voicemail:
| Option | Behavior |
|---|---|
| Let the agent decide | The prompt and conversation context determine whether to speak or hang up. |
| Hang up silently | End without leaving a message. |
| Leave a message, then hang up | Speak the configured message and end the call. |
Voicemail messages can contain up to 2,000 characters and support
{agent_name} and {org_name}. See
Pricing for how call time is
metered.
Consent announcement
By default, a short announcement at the start of every call tells the caller that they are speaking with an AI assistant and that the call is recorded. You can edit the announcement text, up to 2,000 characters; it plays verbatim in the agent's language.
Disabling the announcement on an eligible agent requires an organization admin to affirm that the organization will provide any legally required notice and obtain any legally required consent. Re-enabling and later disabling it requires a new affirmation. Review the recording consent laws guide before changing this setting.
Silence check-ins
When enabled, the agent checks whether the caller is still present after a period of silence, repeats up to your limit, then hangs up:
- Seconds before check-in: 10–120 seconds.
- Maximum check-ins: 1–10.
The defaults are 15 seconds and 3 check-ins.
Builder tabs and lifecycle
| Tab or action | Purpose |
|---|---|
| Live / Talk | Speak with the current draft in your browser and inspect transcript and tool activity. |
| Calls | Review calls handled by this agent. |
| A/B | Create prompt or configuration variants and compare live outcomes. |
| Simulate | Run saved or ad-hoc AI-caller scenarios against the draft. |
| Validation | Replay frozen real-call turns against the draft before deployment. |
| History | Compare deployed revisions and restore one into the draft. |
| Discard | Revert every pending draft setting to the deployed version. |
| Deploy | Atomically promote the complete draft and create a revision. |
If another editor saves the same agent after you loaded it, ThunderPhone stops the conflicting save or deploy and asks you to refresh rather than overwriting their changes.
Manage agents from the list
The Voice Agents page also supports organization-level lifecycle actions:
- Duplicate an agent as a new starting point in the same organization.
- Transfer an agent to another organization you belong to. Copy keeps the source; Move removes it from the current organization and requires administrator access.
- Select one or more agents and export their displayed configuration as CSV or JSON.
- Delete one agent, or bulk-delete selected agents, after confirmation.
Copying or moving an agent across organizations does not silently grant the destination organization access to source-only connections. Review the copied agent's app, API, knowledge, MCP, phone-number, and widget attachments before deploying it there.