Why Supafone#

Choose the speaking model without rebuilding the agent. Keep Supervisor alongside it.

Supafone brings Ultravox, OpenAI, Gemini, Grok and Smallest AI Hydra into one S2S routing hub. Agent Factory keeps your instructions, tools and call stages; Supervisor adds a separate reasoning model that can guide the conversation.

Use one Supafone API key, or bring your own speaking-model and Supervisor keys. The two choices are independent, so you can mix your own provider access with Supafone's managed services. Start with a supervised agent or connect your keys.

Change the speaking model without rebuilding the agent#

The S2S harness keeps a native agent's prompt, supported tools, custom stages, server-side model credentials, and browser or phone transport together. Agent Factory creates that agent, then the shared SupafoneS2S provider classes choose Ultravox, OpenAI, Gemini, Grok, or Smallest AI Hydra. The native catalog has six model choices; Ultravox retains its default managed runtime. Configured platform keys make BYOK optional. Model changes apply to new sessions, with a voice valid for the selected model.

See the shared interface and native model support and limits. Hydra has no live transcript stream and keeps its persona and voice fixed per provider session. All five families share the workflow and reasoning layers; external TTS, language profiles and carrier controls retain their own limits. See Shared runtime, Manager and teams.

Problems we repeatedly encountered#

Problem	Failure in production	Innovation in the package
Self-supervision	The speaking model misses cross-turn intent, emotion, workflow drift, and unsupported claims	Supafone Supervisor maintains a separate belief and directive loop off the audio hot path
Provider fragmentation	Every platform emits different transcript, tool, lifecycle, and control events	Canonical event algebra and 14 audited adapters create one runtime contract
Weak intervention controls	A generic prompt cannot safely alter an active call	Capability-aware compilation chooses native control, developer-owned context, host hook, observation, or no action
Tool hallucination	The agent says a booking, transfer, or delivery happened before the tool confirms it	Truth state separates verified outcomes from conversational language
Repeated agent engineering	Every customer brief becomes another prompt, router, stage graph, and webhook project	Agent Factory creates an inspectable plan plus managed delivery primitives
Manual testing	A few employee test calls miss the scenarios real callers produce	Objective-driven adversarial QA generates cases from the actual agent contract
No stable quality score	Generic LLM scores fluctuate without an operational target	SSR grading converts nominal verdicts into inspectable score distributions
Scattered operations	Calls, recordings, transcripts, and decisions live in separate vendor consoles	Durable activity APIs and telemetry expose one history to SDKs and product UIs
Multilingual discontinuity	Language changes duplicate transcripts, lose state, or use the wrong voice	Transcript-authority rules and opt-in language/voice profiles preserve one canonical call
Rebuilt customer infrastructure	Phone, WebRTC, SMS, campaigns, numbers, signing, and writebacks are implemented repeatedly	Unified SDK, REST, and MCP surfaces expose the surrounding operating system

The design response#

text

production call problem
  -> canonical event
  -> deterministic call state
  -> Supafone Supervisor belief and directive
  -> confidence, truth, and policy gate
  -> provider-aware compiler
  -> native action or safe no-op

The same call state also feeds replay, QA, telemetry, and optimization.

The architecture follows four rules:

The live call remains primary. Supervision never blocks the speaking

agent.

Facts and warmth remain separate. Empathy cannot override tool truth,

consent, or policy.

Capability is explicit. Supafone never pretends a provider supports a

control it does not expose.

Evidence drives improvement. Calls can be replayed, graded, compared,

and used to improve standing directives.

What developers stop rebuilding#

Agent and stage planning
Provider event normalization
Mid-call supervision
Truth and consent state
TTS, STT, and telephony selection
Phone and WebRTC delivery
Recordings and transcripts
Post-call classification
Adversarial QA and grading
Campaign, messaging, and artifact workflows
Operational logs and activity APIs

Continue with Framework coverage to see exactly how the runtime maps onto each supported platform, then use the SDK quickstart to create or supervise an agent.

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