---
title: Custom agents
description: Changing the built-in agents and adding your own.
url: https://docs-v3-preview.elastic.dev/agents/custom-agents
---

# Custom agents
Every agent is an `[agents.<name>]` table. The built-in ones (claude, codex, cursor, pi, opencode, gemini) can be
changed field by field; any other name adds an agent.
```toml
[agents.claude]
command = "claude"
plan = "--permission-mode plan"
resume = "--resume {id}"

[agents.mytool]
command = "mytool --model fast"
prompt = "argument"
```


| Field                      |                                                                                                                 |
|----------------------------|-----------------------------------------------------------------------------------------------------------------|
| `command`                  | The command line that starts the agent.                                                                         |
| `prompt`                   | How the prompt reaches it: `argument` (appended), `stdin` (piped in), `paste` or `file`.                        |
| `plan`                     | Arguments for **Plan first** in Start work.                                                                     |
| `resume`                   | Arguments that resume a session; `{id}` is the agent's session id. Without it, a resumed session starts fresh.  |
| `[agents.<name>.profiles]` | Named command lines, `name = "command"`.                                                                        |
| `[agents.<name>.patterns]` | Screen patterns per state; see [Reading the screen](https://docs-v3-preview.elastic.dev/agents/screen-reading). |

`default_agent` under `[sessions]` picks the agent Start work selects first. Settings (`⌘,`) edits the same fields.