Bland AI API + MCP vs Hume EVI (Empathic Voice Interface)

Bland AI API + MCP

One per-minute rate covering STT, LLM, TTS and telephony, $0.14 on Start and $0.12 on Build. No OpenAPI document.

Hume EVI (Empathic Voice Interface)

Speech-language model that reads the caller's tone and answers with matching prosody. One account-wide key, sent in the WebSocket and Twilio webhook URLs.

Bland AI API + MCP

1. Call wait_for_call (it waits up to 45 seconds) instead of polling get_call_log
2. Send destructive MCP tools a second time with the confirmation argument
3. Space calls to the same number at least 10 seconds apart or expect a 429
4. Budget $0.015 for every outbound attempt, including ones that never connect
5. Run validate_pathway before saving a pathway graph

Hume EVI (Empathic Voice Interface)

1. Create a config with a voice first, EVI 3 has no default
2. Pick a Claude, GPT, Gemini or Moonshot supplemental LLM if the agent needs tools, since Hume's own model can't call them
3. Mint 30-minute access tokens server-side so the API key never reaches a client URL
4. Turn on 'Do not retain data' and 'Do not use for training' at app.hume.ai before sensitive calls
5. Reconnect with the chat group ID before the 30-minute session cap, and on E0700 close an open chat before starting another