Runs onWrit CloudDesktopSelf-hosted
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Evaluate (JS)
The evaluate step runs a snippet of JavaScript in the page context and captures the returned value — the most flexible way to read computed values, parse embedded JSON, or shape complex output.
In a workflow, this is a step object with "type": "evaluate". Steps run in order, and each step can read the outputs of the steps before it. See the full workflows reference for the 30+ step types.
Writ runs on your own accounts, with your own credentials and data, on sites you are authorized to use.
Fields
| Field | Type | Description |
|---|---|---|
script required | string | A JS expression or function body that returns a serializable value. |
Example
A single evaluate step as it appears in a workflow's steps array:
{
"type": "evaluate",
"config": { "script": "return JSON.parse(document.querySelector('#data').textContent)" }
}How it behaves
- Great for sites that embed their data as JSON in a script tag.
- Scribe can write the evaluate step for you from a description of what you want back.
Where it runs
The evaluate step executes wherever the run executes. On your local or BYO agent there is no compute charge and the agent can reach intranet-only systems; on Writ cloud the run is metered by running time (~$0.12 per browser-hour, from your plan’s included usage wallet.
What next
- Workflows - the full step vocabulary and the workflow object.
- Recorder - capture steps by clicking through a site.
- Managed endpoints - turn the workflow into a REST endpoint, or an MCP tool.