> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://poly-ai.ferndocs.com/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://poly-ai.ferndocs.com/_mcp/server.

# Agents API

> Build, configure, and deploy PolyAI agents programmatically. Manage agents, branches, knowledge bases, telephony, and deployments from your own systems.

The Agents API is a set of REST endpoints for building and shipping PolyAI agents without the UI. It covers the full agent lifecycle: create the agent, branch for parallel work, edit behavior and knowledge, provision telephony, publish through environments, and tweak runtime values after launch.

Use it when you want to automate agent setup from your own tooling — CRM workflows, CCaaS provisioning, internal platforms, or coding agents — instead of clicking through Agent Studio.

> **Note**
>
> Also known as the **builder APIs** or **Agent Studio APIs**. This reference covers the same surface area.

## How it differs from the Conversations API

The Agents API is the **build and deploy** layer. The [Conversations API](/api-reference/legacy/conversations-api-v-3-legacy/overview) is the **read and analyze** layer. They're separate services with separate base URLs, auth, and audiences.

|                 | Agents API                         | Conversations API                        |
| --------------- | ---------------------------------- | ---------------------------------------- |
| **Purpose**     | Build and deploy agents            | Read call data and transcripts           |
| **Direction**   | Write (create, update, deploy)     | Read (query, retrieve)                   |
| **Base URL**    | `api.{region}.poly.ai/v1/agents/…` | `api.{region}.platform.polyai.app/v3/…`  |
| **Auth**        | API key (workspace-scoped)         | API key (project-scoped)                 |
| **Who uses it** | Developers automating agent builds | Analysts, integrations pulling call data |

If you want to ship an agent change, use the Agents API. If you want to know what happened in a call, use the Conversations API. See [Getting started](/api-reference/api-reference/overview) for the full distinction across all API families.

## Resource model

The Agents API is organized around a small set of nested resources:

```
account
 ├── agent                  # top-level agent resource (created/listed under account)
 └── voice-library          # account-scoped voice catalog (register, list, sample)

agent
 ├── branch                 # isolated working copy
 │    ├── behavior          # system prompt and interaction rules
 │    ├── knowledge-base    # topics and RAG
 │    ├── attributes        # variant dimensions
 │    └── variants          # site-specific overrides
 ├── deployment             # published version per environment
 ├── telephony
 │    ├── connector         # voice-infra binding
 │    └── phone-number      # E.164 number routed to a connector
 └── real-time-config       # runtime values editable without publishing
```

Agents and voice library entries are scoped to an **account**. Everything inside an agent except deployments, telephony, and real-time configs is scoped to a **branch**. The default branch is `main`; create additional branches for parallel development and merge them back.

## Base URL

The Agents API uses the same regional base URL family as [Alerts](/api-reference/monitoring/alerts-api/overview) and [Webhooks](/api-reference/monitoring/webhooks-api/overview):

| Region | Base URL                     |
| ------ | ---------------------------- |
| US     | `https://api.us.poly.ai`     |
| EU     | `https://api.eu.poly.ai`     |
| UK     | `https://api.uk.poly.ai`     |
| Studio | `https://api.studio.poly.ai` |

Most Agents API paths are prefixed with `/v1/agents/{agentId}/…`. Account-scoped endpoints (listing/creating agents, voice library) are prefixed with `/v1/accounts/{accountId}/…`.

> **Warning**
>
> Do not use `https://api.poly.ai` without a region prefix — it returns an error. Always include the region.

## Authentication

All endpoints authenticate with an API key sent in the `x-api-key` header. Keys are scoped to a workspace.

```bash
curl https://api.us.poly.ai/v1/accounts/ACCOUNT_ID/agents \
  -H "x-api-key: YOUR_API_KEY"
```

> **Note**
>
> API keys for the Agents API are not yet available through self-service. Contact your PolyAI representative to request access.

## Quick start

### 1. Create an agent

```bash
curl -X POST https://api.us.poly.ai/v1/accounts/ACCOUNT_ID/agents \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Support Agent",
    "description": "Handles Tier 1 support for the US market"
  }'
```

The response includes an `agentId` and a default `main` branch.

### 2. Update the agent's behavior

```bash
curl -X PATCH https://api.us.poly.ai/v1/agents/AGENT_ID/branches/main/behavior \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "behavior": "You are a friendly, concise support agent..."
  }'
```

### 3. Add a knowledge base topic

```bash
curl -X POST https://api.us.poly.ai/v1/agents/AGENT_ID/branches/main/knowledge-base/topics \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Password reset",
    "content": "Users can reset their password by..."
  }'
```

### 4. Publish to sandbox

```bash
curl -X POST https://api.us.poly.ai/v1/agents/AGENT_ID/deployments/publish \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "environment": "sandbox" }'
```

### 5. Promote to pre-release, then live

```bash
curl -X POST https://api.us.poly.ai/v1/agents/AGENT_ID/deployments/DEPLOYMENT_ID/promote \
  -H "x-api-key: YOUR_API_KEY"
```

## Environments

Deployments run in one of three environments:

| Environment   | Purpose                                                   |
| ------------- | --------------------------------------------------------- |
| `sandbox`     | Safe space for testing without affecting production calls |
| `pre-release` | Staging for final validation before going live            |
| `live`        | Production — serves real customer traffic                 |

Use `publish` to push a draft into `sandbox`, then `promote` to move through `pre-release` and `live`. Use `rollback` to revert a deployment. See [Environments](/agent-studio/deployments/overview) for the full model.

## Branches

Branches are isolated working copies of an agent. Create a branch for any non-trivial change:

```bash
curl -X POST https://api.us.poly.ai/v1/agents/AGENT_ID/branches \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "name": "experiment-new-greeting" }'
```

Merge back to `main` when you're ready:

```bash
curl -X POST https://api.us.poly.ai/v1/agents/AGENT_ID/branches/BRANCH_ID/merge \
  -H "x-api-key: YOUR_API_KEY"
```

## Real-time configs

Real-time configs let you change runtime values (opening hours, seasonal messaging, holiday flags) without a publish cycle. Updates take effect immediately.

Define a JSON Schema for a config page, then PATCH variables against it:

```bash
curl -X PATCH https://api.us.poly.ai/v1/agents/AGENT_ID/real-time-configs/live/variables \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "variables": { "open_hour": 8, "close_hour": 22 } }'
```

## Variants

Variants let you run one agent across many sites — hotel chains, restaurant groups, franchises — with site-specific values (phone number, address, hours). Define attributes (dimensions), then create variants (combinations).

See [Variants](/agent-studio/knowledge/variants/overview) for the conceptual model.

## Error responses

| Status | Description                                            |
| ------ | ------------------------------------------------------ |
| 400    | Validation error - check request body or parameters    |
| 401    | Missing or invalid API key                             |
| 403    | API key lacks permission for the workspace or resource |
| 404    | Resource not found                                     |
| 409    | Conflict - e.g. merging a branch with diverged state   |
| 422    | Malformed ID or schema validation error                |
| 500    | Internal server error                                  |

### Example error response

```json
{
  "message": "Validation failed",
  "errors": [
    {
      "field": "name",
      "message": "must be between 1 and 128 characters"
    }
  ]
}
```

## Related

#### [Environments](/agent-studio/deployments/overview)

How sandbox, pre-release, and live environments fit together.

#### [Variants](/agent-studio/knowledge/variants/overview)

Run one agent across many sites with attribute-driven variants.

#### [Telephony](/agent-studio/voice/numbers/overview)

Provision phone numbers and route them to connectors.

#### [FAQs](/agent-studio/knowledge/fa-qs/fa-qs)

How knowledge base topics power retrieval and actions.