> For the index of every page in Orbital's docs, read https://docs.beta.runorbital.dev/llms.txt.

# Write your first workflow

> Run the smallest complete workflow: one agent step and one terminal

Write a [workflow](/workflows/) with one agent step and one terminal, then run it. It is the smallest workflow that does anything.

```dot title="minimal.dot"
digraph hello {
  graph [version="1", entry="hello"]
  hello [tool_access="Read only", prompt="Reply with one sentence explaining the goal: {{ inputs.goal }}."]
  done [shape="Msquare"]
  hello -> done
}
```

`hello` is an agent step. It has the Read only tool access, so it can read files but cannot change them. Codex reads files through commands that its read-only sandbox prevents from writing. `done` is a terminal, and the edge between them is the whole route. Every other guide builds on this with more steps and edges.

![hello → done. One prompt followed by a successful terminal.](/minimal.svg?v=b911ee569f)

## Before you start

You need a harness you have signed in to, and a project in Orbital. Any project works. It does not need to be a Git repository, unless you run the example with Codex, which needs one. See [Projects and folders](/projects/).

## 1. Save the workflow

[Download the example](/minimal.zip) and unpack it into your workflow library, `~/.orbital/workflows/`. Keep every relative path. You can also [download minimal.dot](/examples/minimal/minimal.dot) on its own.

## 2. Validate it

```sh
orbital validate ~/.orbital/workflows/minimal.dot
```

Validation calls no agent.

## 3. Start a run

Choose **New task** and pick any project. Choose the `minimal` workflow and your harness. One project serves every example.

![The Start page asks what to do in the selected project, with a box for the goal, a harness picker, a workflow picker and a Chat or Workflow switch.](/screenshots/start-page.webp?v=0428f5d705)

*Pick the workflow and harness beside the goal box.*

Set the goal to "Explain what a workflow is", and start the run. The `hello` step returns a sentence, then `done` ends the run successfully.

## Related

- [Write prompts](/workflows/write-prompts/): read run values in a prompt.
- [Add branches](/workflows/add-branches/): send a run to different steps.
- [Node types](/reference/node-types/): the kinds of step you can add.
- [Research report](/examples/research-report/): a workflow that touches no code.
- [Workflows](/workflows/): where Orbital finds workflows and how to validate them.