# Built-ins Overview

> Built-in harness types and capabilities that ship with Everruns. Harnesses define reusable behavior; Agent Sandbox Template bindings select compute.

Source: <https://everruns.com/docs/built-ins/>

Everruns ships with built-in **harness types** and **capabilities** that provide the foundation for agent sessions.

## Harnesses

A harness defines reusable session behavior: system prompt, default model, starter files, network policy, and bundled capabilities. Every session is assigned a harness. An Agent [Sandbox Template binding](https://everruns.com/docs/features/sandbox-templates/) independently selects the filesystem and compute target for new sessions.

| Harness                                                                                | Description                              | Capabilities                                                                      |
| -------------------------------------------------------------------------------------- | ---------------------------------------- | --------------------------------------------------------------------------------- |
| [Base](https://everruns.com/docs/built-ins/harnesses/base/)                            | System essentials every agent needs      | Compaction, error disclosure, tool-call repair, loop detection, approval guidance |
| [Conversation](https://everruns.com/docs/built-ins/harnesses/conversation/)            | Default for dialogue, no workspace       | Base + structured questions, message timestamps                                   |
| [Worker](https://everruns.com/docs/built-ins/harnesses/worker/)                        | Worker without compute                   | Base + files, AGENTS.md, skills, long context, budgeting, subagents, tasks        |
| [Bashkit Worker](https://everruns.com/docs/built-ins/harnesses/bashkit-worker/)        | Worker with the Bashkit virtual shell    | Worker + Bashkit shell, fixed Sandbox Template                                    |
| [Sandbox Worker](https://everruns.com/docs/built-ins/harnesses/sandbox-worker/)        | Worker with a full sandbox               | Worker + the shell of a container or managed Sandbox Template                     |
| [Worker Base (deprecated)](https://everruns.com/docs/built-ins/harnesses/worker-base/) | Deprecated legacy bundle                 | Files, bash, project instructions                                                 |
| [Generic (deprecated)](https://everruns.com/docs/built-ins/harnesses/generic/)         | Deprecated legacy bundle                 | 25 configured                                                                     |
| [Data Analyst](https://everruns.com/docs/built-ins/harnesses/data-analyst/)            | SQL databases, charts, persistent memory | Bashkit Worker + data capabilities; available as a built-in example               |

[Platform Chat](https://everruns.com/docs/built-ins/harnesses/platform-chat/) is a managed Agent bound to Bashkit Worker.

![Built-in harness tree](https://everruns.com/docs/_astro/harness-tree.CeZx85x1_1TFtua.svg)

See the [Harnesses feature guide](https://everruns.com/docs/features/harnesses/) for harness selection, API management, and the prompt stack model.

## Harness Examples

Harness examples are adoptable templates. Import them when you want a preconfigured starting point, then customize the resulting org-owned harness.

| Example      | Import Name    | Description                                                                                                                                 |
| ------------ | -------------- | ------------------------------------------------------------------------------------------------------------------------------------------- |
| Coding       | `coding`       | Sandbox Worker + coding behavior and GitHub Scout; the Agent Sandbox Template binding selects Daytona, a container, or another full sandbox |
| Data Analyst | `data-analyst` | Bashkit Worker + SQL databases, charts, persistent memory, and curated data knowledge                                                       |

## Capabilities

Capabilities are modular units that extend what an agent can do. Each can contribute tools, system prompt additions, and UI features.

Browse the full [Capabilities reference](https://everruns.com/docs/capabilities/) for the complete list organized by category.