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docs ▸Teach the agent ▸Step reference

Runs onWrit CloudDesktopSelf-hosted

Authentication step

Login (request)

The login_post step replays a sign-in as an HTTP request instead of filling a form — mechanically an api_call whose body carries your credentials. Because the request runs inside the page, the session cookie it sets is reused by every step that follows.

In a workflow, this is a step object with "type": "login_post". 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

FieldTypeDescription
url required string The sign-in endpoint.
method string Usually POST.
body json The request body; credential placeholders resolve at run time, never stored in the recipe.
headers map Request headers if the endpoint needs them.

Example

A single login_post step as it appears in a workflow's steps array:

{
  "type": "login_post",
  "config": {
    "method": "POST",
    "url": "https://example.com/api/login",
    "body": { "email": "{{email}}", "password": "{{vault:password}}" }
  }
}

How it behaves

  • A distinct type from api_call so a sign-in is never treated as a data deliverable.
  • Credentials resolve from the vault at run time; nothing sensitive lives in the workflow.
  • Only sign in to accounts you own or are authorized to use.

Where it runs

The login_post 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.