> ## Documentation Index
> Fetch the complete documentation index at: https://docs.callers.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Glossary

> Short definitions of the terms used across Callers, from A2A connections to webhooks.

Definitions of the terms you'll see in the Callers dashboard, docs, and API.

## A

| Term | Definition |
| - | - |
| **A2A connection** | A link to an external AI agent over the Agent-to-Agent (A2A) protocol. Your Callers agent can pass the conversation to it and use its answers during a call. See [A2A connections](https://docs.callers.ai/documentation/integrations/a2a-connections.md). |
| **Action** | A step that connects the agent to another system: an App Center action, a custom HTTP request, or custom code. Actions run before, during, or after a conversation. See [Actions](https://docs.callers.ai/documentation/build-your-agent/agent-actions.md). |
| **Agent** | One AI worker with one job, such as confirming appointments or answering a support line. An agent holds its script, voice, channels, schedule, contacts, and results. Called "campaign" before September 2026, and still `campaign` in parts of the API. See [Create an agent](https://docs.callers.ai/documentation/build-your-agent/starting-a-new-agent.md). |
| **Agent group** | A folder on the **Agents** page for organizing agents. |
| **AI suggestions** | Recommendations Callers generates from your agent's results, such as steps with high drop-off or high interruption rates, or questions the agent missed. |
| **App Center** | The catalog of integrations (CRMs, calendars, spreadsheets, messaging, telephony) you connect once and use in actions and triggers. See [App Center](https://docs.callers.ai/documentation/integrations/app-center.md). |
| **Availability** | The hours and time zone in which an agent may call, plus its retry and concurrency rules. See [Scheduling and retries](https://docs.callers.ai/documentation/contacts/scheduling-and-retries.md). |

## B–C

| Term | Definition |
| - | - |
| **Background sound** | Ambient audio, such as office noise, played under the agent's voice on SIP calls. See [Voices and sounds](https://docs.callers.ai/documentation/voice/voices-and-sounds.md). |
| **Block** | A stage of the conversation on the script canvas, such as "Greeting" or "Qualify". Also called a node. Blocks contain **steps** and can branch into **subflows**. |
| **Call Data** | Information about the current call, such as the contact's phone number or the number the agent called from, that you can insert into steps and actions. |
| **Channel** | How an agent reaches people: **Voice** (phone and web calls), **Text** (SMS and WhatsApp), or **Email**. |
| **Concurrency** | How many conversations an agent runs at the same time. Outgoing voice agents default to 10 parallel calls (**Max Outgoing Calls in Parallel**). |
| **Contact** | A person the agent talks to, with a name, one or more phone numbers or an email address, and data for **variables**. See [Uploading contacts](https://docs.callers.ai/documentation/using-callers/uploading-contacts.md). |
| **Contact memory** | Facts the AI remembers about a contact across conversations, used to personalize later calls. See [Contact memory](https://docs.callers.ai/documentation/contacts/contact-memory.md). |
| **Contact status** | Where a contact stands, such as **New**, **Pending Retry**, **Interested**, **Not interested**, **Call later**, or **Do not call**. See [Statuses and outcomes](https://docs.callers.ai/documentation/using-callers/call-statuses.md). |

## D–I

| Term | Definition |
| - | - |
| **Dialing strategy** | How an agent picks which of its numbers to call from: **Rotate Numbers**, **Prefer Local Numbers**, or **Auto Optimize**. See [Phone numbers and caller ID](https://docs.callers.ai/documentation/contacts/phone-numbers-and-caller-id.md). |
| **Do Not Call (DNC) list** | Numbers that must not be called. Callers keeps an account-level list and can check the US Federal DNC Registry and state lists. See [Do Not Call](https://docs.callers.ai/documentation/contacts/do-not-call.md). |
| **DTMF / keypad input** | Digits the contact types on their phone keypad, such as an account number. See [Keypad input](https://docs.callers.ai/documentation/voice/keypad-input.md). |
| **Draft** | The editable version of an agent. Changes in a draft don't affect live conversations until you **publish**. |
| **Guardrails** | Rules that check what the agent is about to say, such as "No medical advice", and end the conversation, transfer to a human, or regenerate the reply when a rule is triggered. See [Instructions and guardrails](https://docs.callers.ai/documentation/build-your-agent/instructions-and-guardrails.md). |
| **Human operator** | A person on your team who takes transferred calls in the browser from a queue. See [Human operators](https://docs.callers.ai/documentation/human-operators/overview.md). |
| **Insights Mode** | A view of the script that shows, for each step, how many conversations reached it, hung up there, or interrupted. See [Agent results and insights](https://docs.callers.ai/documentation/using-callers/agent-insights.md). |
| **Instructions** | Hidden guidance for the AI, set for the whole agent or inline in a step, that shapes behavior without being spoken. |

## K–P

| Term | Definition |
| - | - |
| **Key question** | A structured question answered from the transcript after each conversation, such as "Budget" (number) or "Interested in a demo?" (yes/no). See [Post-call analysis](https://docs.callers.ai/documentation/using-callers/key-questions.md). |
| **Knowledge base** | Documents, web pages, and text the agent can search to answer questions. See [Knowledge base](https://docs.callers.ai/documentation/using-callers/knowledge-base.md). |
| **Patience level** | How long the agent waits after the contact stops talking before it replies, from **Fast** to **Slow**. See [Conversation dynamics](https://docs.callers.ai/documentation/voice/conversation-dynamics.md). |
| **Post-call action** | An action that runs after a conversation, often depending on its outcome, such as updating a CRM record. |
| **Post-call analysis** | The AI's review of a finished conversation: a summary, answers to **key questions**, sentiment, and the **success criteria** result. |
| **Pre-call chat** | A text message sent before calling, asking whether the contact wants the call. See [Pre-call chat](https://docs.callers.ai/documentation/build-your-agent/pre-call-chat.md). |
| **Pre-conversation action** | An action that runs before a call, before every attempt or only the first, usually to fetch data into **variables**. |
| **Pronunciation dictionary** | A list of words with how they should sound, used to fix how the agent says names and terms. See [Pronunciation dictionary](https://docs.callers.ai/documentation/voice/pronunciation-dictionary.md). |
| **Publish** | Make a saved **draft** the live version of an agent. See [Versions and split traffic](https://docs.callers.ai/documentation/build-your-agent/versions-and-split-traffic.md). |

## R–S

| Term | Definition |
| - | - |
| **Retry** | Another attempt to reach a contact who didn't answer, scheduled according to the agent's retry rules. |
| **Scenario** | A response the agent can use at any point in the conversation when the contact says something that matches it, such as an objection or "call me later". See [Scenarios](https://docs.callers.ai/documentation/build-your-agent/agent-scenarios.md). |
| **Script** | The conversation flow of an agent, built from **blocks** and **steps** on a canvas. See [Script editor](https://docs.callers.ai/documentation/build-your-agent/agent-script.md). |
| **SIP** | The protocol used to connect your own carrier or PBX to Callers. See [SIP integration](https://docs.callers.ai/documentation/integrations/sip.md). |
| **Split traffic** | Running several published versions of an agent at once with a share of conversations each, to compare results. |
| **Step** | A single thing the agent does inside a block: say or ask something, transfer the call, send an SMS or email, book a meeting, run an action, wait, or end the call. See [Steps](https://docs.callers.ai/documentation/build-your-agent/customizing-steps.md). |
| **Studio Chat** | The AI assistant in the dashboard that builds and edits agents and answers questions about your results. See [Studio Chat](https://docs.callers.ai/documentation/build-your-agent/studio-chat.md). |
| **Subaccount** | A separate account under your main account, used by agencies for each client or by companies for each business unit. See [Managing subaccounts](https://docs.callers.ai/documentation/agencies/managing-subaccounts.md). |
| **Subflow** | A branch of the script that the conversation follows depending on what the contact says. |
| **Success criteria** | The rules that decide whether a conversation reached its goal and how other outcomes are classified. Formerly "interest criteria". See [Success criteria](https://docs.callers.ai/documentation/results/success-criteria.md). |

## T–W

| Term | Definition |
| - | - |
| **Test call** | A call to your own phone or browser to try an agent before it goes live. See [Testing your agent](https://docs.callers.ai/documentation/build-your-agent/testing-your-agent.md). |
| **Transcript variable** | A value the AI extracts from what the contact said, such as a date or a number, so it can be passed to an action. |
| **Trigger** | An event in a connected app that adds or archives a contact in an agent automatically. See [Triggers](https://docs.callers.ai/documentation/integrations/triggers.md). |
| **Variable** | A placeholder such as `{{name}}` in the script, filled for each contact from contact data, actions, or built-in values. See [Variables](https://docs.callers.ai/documentation/build-your-agent/agent-variables.md). |
| **Version** | A saved state of an agent's script and settings. Versions can be **draft** or published, and you can restore earlier ones. |
| **Voicemail detection** | Callers' check, during and after the call, for whether a voicemail system answered. See [Voicemail and screening](https://docs.callers.ai/documentation/voice/voicemail-and-screening.md). |
| **Warm transfer** | A transfer where the agent briefs the person receiving the call before connecting the contact. See [Call transfers](https://docs.callers.ai/documentation/voice/call-transfers.md). |
| **Webhook** | An HTTP request Callers sends to your URL when a conversation event happens, such as a call finishing. See [Webhooks](https://docs.callers.ai/documentation/webhook/webhook-overview.md). |
| **White label** | Presenting Callers to your clients under your own logo, name, and domain. See [White label](https://docs.callers.ai/documentation/agencies/white-label.md). |
| **Widget** | The embeddable component that lets website visitors talk or chat with your agent. See [Installing the widget](https://docs.callers.ai/documentation/widget-agents/installing-the-widget.md). |

## Related

> **[Core concepts](https://docs.callers.ai/documentation/get-started/core-concepts.md)**
>
> How agents, scripts, contacts, and results fit together.

> **[FAQ](https://docs.callers.ai/documentation/resources/faq.md)**
>
> Short answers to common questions.

> **[Quickstart](https://docs.callers.ai/documentation/get-started/quickstart.md)**
>
> Build and test your first agent.

> **[API introduction](https://docs.callers.ai/api-reference/introduction.md)**
>
> Field names and conventions in the REST API.


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