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

# Agent SDK

> Build, host, and connect your agents to the real world all on one platform.

The Agent SDK spans server and client. The server side brings together the **Agent
Runtime**, **Harness Core**, **AI Adapter**, **Tools Adapter**, and **Comms
Adapter**. The client side adds the **Client SDK**.

<Warning>
  **Beta:** The Agent SDK is taking shape in stages. Start today with the available
  **Agent Runtime** capabilities as we expand toward the full server-and-client
  experience shown below. Explore the [Runtime API](/docs/agent-sdk/api-reference).
</Warning>

## The Agent SDK at a Glance

The Agent SDK has three coordinated surfaces:

1. **Agent harness (server):** four components work together:
   * A generic **Harness Core** owns the thinking loop, tool calls, and remember/recall
     cycle found in agent frameworks.
   * The **AI Adapter** connects generic model calls to Telnyx Inference.
   * The **Tools Adapter** connects generic tool calls to capabilities such as
     search, browsing, RAG, and MCP.
   * The **Comms Adapter** connects generic events and actions to the
     Telnyx communications suite.
2. **Agent runtime (server):** persistent identity, messages, state, schedules, queues,
   connections, RPC, and lifecycle.
3. **Client SDK (client):** an optional connection layer for browsers and applications
   to reconnect, observe state and messages, and invoke typed RPC methods.

The Agent runtime spans the Telnyx Edge Compute and Storage foundation:
`StatefulActor`, persistent storage and SQL, alarms, WebSockets, RPC, bindings,
object storage, and CloudFS. The generic Harness Core uses the runtime for persistent
memory. The three adapters connect that core to Telnyx Inference, tools, and the
communications suite without becoming new runtime layers.

The separation is deliberate:

* **Agent Runtime** simplifies connections, state persistence, and other infrastructure.
* **Harness Core** decides what to do each turn—the standard loop in every agent framework.
* **Adapters** connect the agent to Telnyx AI, tools, and communications suites.
* **Client SDK** speaks the same protocol as the server agent.

Together, these layers handle the plumbing so you can focus on your business-specific
agent logic.

## Three Ways to Consume the Server Stack

Choose how much of the stack you want to take on. Start from the primitives, runtime,
or harness; the layers below remain available.

| Layer         | Way 1: Build from Primitives | Way 2: Start from Runtime | Way 3: Start from Harness |
| ------------- | ---------------------------- | ------------------------- | ------------------------- |
| Your Code     | **You Own**                  | **You Own**               | **You Own**               |
| Agent Harness | **You Own**                  | **You Own**               | **Telnyx Owns**           |
| Agent Runtime | **You Own**                  | **Telnyx Owns**           | **Telnyx Owns**           |

**Shared Foundation:** Edge Compute + Storage

## Where to Go Next

* [Quickstart](/docs/agent-sdk/quickstart) — build a working agent in one file
* [How Agents Run](/docs/agent-sdk/concepts/how-agents-run) — understand the actor execution model
* [Calling LLMs](/docs/agent-sdk/concepts/calling-llms) — compare harness wiring patterns
* [API reference](/docs/agent-sdk/api-reference) — inspect every runtime method and override hook