Create Agent

Create Bolna Agent

Use the current API

• Endpoint: POST https://api.bolna.ai/v2/agent
• Auth: Authorization: Bearer $BOLNA_API_KEY
• Body root: agent_config and agent_prompts
• Response: agent_id and status: created
• Do not use deprecated /agent v1 endpoints for new agents.

Minimum creation flow

1. Confirm the user has BOLNA_API_KEY set.
2. Gather: agent name, use case, language, welcome message, system prompt, LLM provider/model, voice/TTS provider, transcriber/STT provider, telephony provider, webhook URL if needed.
3. Build one conversation task unless the user explicitly asks for extraction, summarization, or advanced flows.
4. Put dynamic variables in prompts with braces, for example {customer_name}.
5. Add matching values later through user_data when making calls.
6. Include conservative call controls: silence hangup, interruption words, max duration, voicemail behavior, inbound limits.
7. POST the payload, then save the returned agent_id.

Request shape

{
  "agent_config": {
    "agent_name": "Support Agent",
    "agent_welcome_message": "Hi {customer_name}, this is Tara from Acme.",
    "webhook_url": null,
    "agent_type": "other",
    "tasks": [
      {
        "task_type": "conversation",
        "tools_config": {
          "llm_agent": {},
          "synthesizer": {},
          "transcriber": {},
          "input": {},
          "output": {},
          "api_tools": null
        },
        "toolchain": {
          "execution": "parallel",
          "pipelines": [["transcriber", "llm", "synthesizer"]]
        },
        "task_config": {}
      }
    ],
    "ingest_source_config": null,
    "calling_guardrails": {
      "call_start_hour": 9,
      "call_end_hour": 18
    }
  },
  "agent_prompts": {
    "task_1": {
      "system_prompt": "You are a concise, helpful voice agent..."
    }
  }
}

Required task blocks

• llm_agent: use simple_llm_agent for normal prompting or knowledgebase_agent when attaching RAG. Use agent_flow_type: streaming for live calls.
• synthesizer: TTS provider, voice, model, streaming, buffer size, audio format.
• transcriber: STT provider, model, language, streaming, sampling rate, encoding, endpointing.
• input and output: telephony provider and audio format.
• toolchain: usually one pipeline: transcriber -> llm -> synthesizer.
• task_config: human conversation controls such as silence timeout, interruption threshold, backchanneling, voicemail, call max duration, whitelist, and unknown caller behavior.

Knowledge bases

1. Create or list knowledge bases with the create-knowledgebase skill.
2. Wait until status is processed.
3. Use the returned vector_id in the agent LLM vector store config.
4. Use a knowledgebase agent only when the voice agent must answer from documents, FAQs, URLs, policies, or product docs.

Function tools

Use setup-tools when the agent must transfer calls, call external HTTP APIs, fetch or book calendar slots, or write to CRM systems. Keep function schemas narrow, with clear descriptions and JSON parameters.

Details to read before complex agents

Read references/agent-config-fields.md for full field guidance, provider choices, dynamic variables, RAG wiring, and gotchas.

Script

python3 create-agent/scripts/create_minimal_agent.py \
  --name "Demo Support Agent" \
  --welcome "Hi {customer_name}, how can I help?" \
  --prompt "You are a helpful support agent. Keep answers brief."

Hindi / Indian-language agent

For an agent serving Indian callers in Hindi:

{
  "agent_config": {
    "agent_name": "Hindi Support Agent",
    "agent_welcome_message": "नमस्ते {customer_name}, मैं Acme से तारा बोल रही हूँ।",
    "tasks": [{
      "task_type": "conversation",
      "tools_config": {
        "llm_agent": {
          "agent_type": "simple_llm_agent",
          "agent_flow_type": "streaming",
          "llm_config": {
            "provider": "openai", "family": "openai", "model": "gpt-4.1-mini",
            "max_tokens": 200, "temperature": 0.2
          }
        },
        "synthesizer": {
          "provider": "sarvam",
          "provider_config": { "voice": "meera", "model": "bulbul-v2" },
          "stream": true, "audio_format": "wav"
        },
        "transcriber": {
          "provider": "deepgram", "model": "nova-3",
          "language": "multi-hi", "stream": true,
          "encoding": "linear16", "sampling_rate": 16000, "endpointing": 700
        },
        "input":  { "provider": "plivo", "format": "wav" },
        "output": { "provider": "plivo", "format": "wav" }
      },
      "toolchain": { "execution": "parallel", "pipelines": [["transcriber","llm","synthesizer"]] }
    }]
  },
  "agent_prompts": { "task_1": { "system_prompt": "आप तारा हैं, Acme की Voice AI सहायक। एक बार में 2 से अधिक वाक्य न बोलें। ग्राहक की भाषा में जवाब दें।" } }
}

Key choices:

• Deepgram multi-hi STT handles Hindi-English code-switching (Hinglish) cleanly.
• Sarvam TTS for native Hindi pronunciation.
• Plivo telephony for Indian 160-series numbers (160 = transactional). Use Vobiz for 140-series promotional.
• Native Devanagari in the system prompt — never phonetic English.
• endpointing: 700 accommodates the longer pauses common in Hindi calls.

See ../prompt-writing/references/multilingual.md for the full multilingual playbook.

Multilingual agents (one agent, many languages on one call)

When you want one agent to take a call that may switch between languages mid-conversation — not one agent per language — enable multilingual_config. Bolna routes each user turn through the right STT/TTS based on which language is being spoken.

{
  "tools_config": {
    "llm_agent": { /* shared LLM across languages */ },
    "synthesizer": { /* default TTS — used when no per-language override fires */ },
    "transcriber": { /* default STT */ },
    "multilingual_config": {
      "enabled": true,
      "active_language": "hi",                          // language the call OPENS in
      "switch_tool_description": "Respond in the language the user is currently speaking. Default to Hindi.",
      "languages": {
        "hi": {
          "agent_name": "Vidya",                        // optional, advanced
          "system_prompt": "आप विद्या हैं... <full Hindi prompt>",
          "synthesizer": {
            "provider": "sarvam",
            "buffer_size": 220,
            "provider_config": { "model": "bulbul:v3", "voice": "Ashutosh", "voice_id": "ashutosh" }
          },
          "transcriber": { "provider": "elevenlabs", "model": "scribe_v2_realtime", "language": "hi" },
          "handoff_message": "एक मिनट, मैं {agent_name} से connect करती हूँ जो {language} बोलती हैं।"
        },
        "en": {
          "agent_name": "Vidya (English)",
          "system_prompt": "You are Vidya, a calm, warm voice agent... <full English prompt>",
          "synthesizer": {
            "provider": "cartesia",
            "buffer_size": 40,
            "provider_config": { "model": "sonic-3.5", "voice": "Callie - Encourager", "voice_id": "00a77add-48d5-4ef6-8157-71e5437b282d" }
          },
          "transcriber": { "provider": "deepgram", "model": "nova-3", "language": "en" },
          "handoff_message": "One moment, connecting you with {agent_name} who speaks {language}."
        }
      }
    }
  }
}

Non-obvious rules:

For the full worked example (Snabbit-style, three languages, per-language STT/TTS), see references/multilingual-config.md.

Second task: post-call extraction (summarization)

The tasks[] array can carry a second task that runs after the call ends, against the transcript. This is the underlying mechanism behind create-disposition.

{
  "tasks": [
    { "task_type": "conversation", /* the live call */ },
    {
      "task_type": "summarization",
      "toolchain": { "execution": "parallel", "pipelines": [["llm"]] },
      "tools_config": {
        "llm_agent": {
          "agent_type": "simple_llm_agent",
          "llm_config": {
            "provider": "openai",
            "model": "gpt-4o-mini",
            "max_tokens": 100,
            "temperature": 0.1,
            "request_json": true     // emit structured JSON instead of free text
          }
        }
      },
      "task_config": { "call_terminate": 90 }
    }
  ]
}

request_json: true is the flag that produces structured extracted_data for the webhook / GET /executions/{id}. Dispositions (create-disposition) and legacy gpt_assistants.custom_questions both ride on this task.

All the task_config knobs

The task_config block has ~25 fields covering latency, interruption, voicemail, silence handling, inbound limits, and noise suppression. Most defaults are sensible. Tune deliberately.

Full reference: references/task-config-fields.md.

Knowledge-base agent (RAG)

When the agent must answer from documents (FAQs, policies, product docs):

{
  "tools_config": {
    "llm_agent": {
      "agent_type": "knowledgebase_agent",
      "agent_flow_type": "streaming",
      "llm_config": { "provider": "openai", "model": "gpt-4o", "max_tokens": 200, "temperature": 0.3 },
      "vector_store": {
        "provider": "lancedb",
        "provider_config": {
          "vector_ids": ["<rag_id_1>", "<rag_id_2>"],
          "similarity_top_k": 8
        }
      }
    }
  }
}

• Create the knowledge base first via create-knowledgebase and wait for status == "processed".
• Use vector_ids[] (array) to attach multiple knowledge bases to one agent.
• gpt-4o is recommended for KB agents — better at synthesising across retrieved chunks than gpt-4.1-mini.

Semantic routes (FAQ short-circuits)

For high-volume FAQs and policy refusals, llm_agent.routes short-circuits common questions with a pre-defined answer — zero LLM cost, near-zero latency:

{
  "llm_agent": {
    "agent_type": "simple_llm_agent",
    "agent_flow_type": "streaming",
    "llm_config": { "provider": "openai", "model": "gpt-4.1-mini", "max_tokens": 200 },
    "routes": [
      {
        "name": "refund_policy",
        "utterances": ["what's your refund policy", "can I get a refund", "how do returns work"],
        "response": "We offer full refunds within 30 days of purchase. I can email you the policy document — want that?",
        "similarity_threshold": 0.85
      },
      {
        "name": "business_hours",
        "utterances": ["what are your hours", "when are you open", "operating hours"],
        "response": "We're open 9 AM to 7 PM IST, Monday through Saturday.",
        "similarity_threshold": 0.85
      }
    ]
  }
}

Routes fire before the LLM runs. Use for FAQs, hard refusals (pricing, competitor questions), and stable policy answers. Don't use for anything that needs to be dynamic per caller.

See also

• references/agent-config-fields.md — full field reference.
• references/multilingual-config.md — one agent, many languages, full worked example.
• references/task-config-fields.md — every task_config knob with default and use case.
• make-call — how to actually dial after creation.
• bolna-graph-agents — switch from a single prompt to a node-based flow.
• setup-tools — add transfer_call, custom HTTP, Cal.com booking.
• create-knowledgebase — generate the vector_id used by knowledgebase agents.
• ../references/providers-matrix.md — picking LLM × STT × TTS × telephony combos.
• ../prompt-writing — how to write the system_prompt.