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A

Agent A complete Voice AI configuration that can make and receive phone calls. An agent bundles together a prompt, a voice pipeline (transcriber + LLM + synthesizer), telephony settings, and optional tools. ASR (Automatic Speech Recognition) See Transcriber. Agent ID A UUID that uniquely identifies an agent in Bolna. Required when making calls or managing the agent via API. Example: 5bc97541-e320-4d95-a3a5-242cfe45621d.

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B

Batch A campaign that places calls to a list of recipients uploaded as a CSV file. Batches are created, scheduled, and tracked via the /batches API endpoints. Batch ID A string identifier for a batch. Example: 3c90c3cc0d444b5088888dd25736052a. Buffer size The number of text characters the synthesizer accumulates before sending the first audio chunk. Smaller buffers start audio sooner; larger buffers produce smoother speech.

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C

Call-disconnected An intermediate execution status — NOT the final state. Fires when the phone line drops, but post-call processing (transcript assembly, cost calculation, extraction) has not yet completed. Always wait for completed. Completed The terminal execution status indicating all post-call processing is done. At this point conversation_duration, total_cost, recording_url, and extracted_data are populated. Concurrency The number of simultaneous active calls your account can run. Visible in GET /user/me as concurrency.max. Contact support to increase. Context details Per-call metadata attached at call time, including recipient_data (the CSV row columns for batch calls) and any custom fields.

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D

DTMF (Dual-Tone Multi-Frequency) Touch-tone signals generated when a caller presses phone keys (0–9, *, #). Used in IVR agents for menu navigation.

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E

Endpointing The process of detecting when a caller has finished speaking. Configured in milliseconds on the transcriber. Too low causes interruptions; too high adds dead air. Execution A single call event — one phone call placed or received. Identified by an execution_id. Contains the full call record: status, transcript, cost, recording URL, extracted data. Execution ID A UUID identifying a single call execution. Used to poll status or retrieve results. Example: b7140255-af33-4608-8e97-04dd944b8e48. Extracted data Structured data automatically pulled from the conversation transcript by post-call extraction (if configured). Returns a JSON object keyed by category and field name.

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G

Graph agent An agent architecture where the conversation is structured as a directed graph of nodes, each with its own prompt and routing rules. Contrast with conversation agent. Guardrail A calling restriction that prevents calls from being placed under certain conditions — time of day, do-not-call lists, daily limits.

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H

Hangup prompt A phrase or condition configured on an agent that triggers the agent to end the call when detected in conversation. Example: when the agent says “Goodbye” or “Have a great day.”

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I

Inbound call A call received by a Bolna agent on a phone number linked to the agent. The caller initiates. IVR (Interactive Voice Response) An agent type that routes callers based on key presses rather than AI conversation. See IVR Inbound Calls.

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K

Knowledge base A collection of documents (PDFs, URLs, text) that an agent can search during conversations using RAG (Retrieval-Augmented Generation). Configured in the LLM tab.

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L

Latency The delay between when a caller finishes speaking and when the agent starts responding. Measured as Time to First Audio (TTFA) in milliseconds. See Latency. LLM (Large Language Model) The AI model that processes the conversation transcript and generates the agent’s responses. Examples: GPT-4.1, Claude, Gemini.

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O

Outbound call A call placed by Bolna to a recipient. Initiated via POST /call or as part of a batch.

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P

Pipeline The ordered chain of processing components for a task: [["transcriber", "llm", "synthesizer"]]. Must be an array of arrays. Prompt The system instruction given to the LLM that defines the agent’s persona, task, and behavior. Written in natural language.

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R

RAG (Retrieval-Augmented Generation) A technique where the LLM is given relevant excerpts from a knowledge base before generating a response, allowing it to answer questions from your documents. Recording URL A URL to the audio recording of the call. Available in telephony_data.recording_url after the execution reaches completed.

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S

Scheduled_at The ISO 8601 timestamp at which a batch should start calling. Must use a numeric UTC offset (e.g. +00:00) — the Z suffix is rejected. Must be at least 2 minutes in the future; Bolna rounds up to the next 10-minute mark. Synthesizer The text-to-speech provider that converts the LLM’s response into spoken audio. Examples: ElevenLabs, Cartesia, Azure TTS.

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T

Task The unit of work inside an agent. A conversation task handles the real-time conversation; an extraction task runs post-call to pull structured data from the transcript. Telephony provider The phone network provider that handles call connections, phone number assignment, and audio transport. Examples: Plivo, Twilio, Exotel. Time to First Audio (TTFA) The latency metric reported per call in latency_data.time_to_first_audio (milliseconds). Measures from end of caller’s utterance to start of agent’s audio response. Toolchain The configuration block that defines the pipeline and execution mode for an agent task. Contains execution (e.g. "sequential") and pipelines (array of arrays). Transcriber The speech-to-text provider that converts caller audio into text in real-time. Examples: Deepgram, Azure Speech, Sarvam. Transcript The full text of the conversation, with speaker labels (assistant: / user:). Available in the execution record after completed.

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W

Wallet The credit balance used to pay for calls. Each call deducts from the wallet based on duration, provider costs, and platform fee. A balance-low execution status means the wallet was empty when the call was attempted. Webhook An HTTP POST that Bolna sends to your server at each execution status change. Delivers the same payload as GET /executions/{id}. Source IP: 13.203.39.153.