Scripts

An agent node calls an AI model at each step to decide what to do. The model reads the page and picks each action from your instructions. That is what you want on a page that changes. It is waste on a page that never changes. In that case, you should convert the node into a script. Give the node a Script and it runs a Playwright script first, before any model call. The same clicks happen every execution, in milliseconds, for no model cost.

Let Astro script it

Ask Astro which nodes are stable enough to script. It writes the script from what the workflow already did, attaches it to the node, and runs it.

Pick the right node

Script a node when all three hold.

The page has been stable for months.
The workflow takes the same actions every execution.
You can name the selectors, or Astro can read them from a past execution.

Leave a node turn by turn in three cases. The page changes. The path branches on what the workflow finds. Or the step is new, and you are still learning the site.

Add a script

Open the node’s Instructions tab. The Script field sits at the top. Select a .js file from the node’s shared directory. The node becomes a scripted node, and an “If the script fails” picker appears beside the field. Remove the script and the node goes back to running turn by turn. Astro does the same thing from the chat. Ask it to script a node and it writes the file, sets the field, and picks a failure action. Nodes covers where a script file lives and how the runtime resolves its path.

What happens when the script runs

The script runs against the live browser session — the same browser the model would have used. Then one of three things happens.

Condition	What the runtime does
A selector transition matches right after the script	Takes that transition. No model call.
The script succeeded and the node has exactly one outbound transition	Takes it. No model call.
Anything else	Calls the model, with the script’s output added as context.

The first two paths are the fast ones. A scripted node with one outbound transition skips the model whenever the script succeeds.

What the script returns

Return value	Effect
An object	Each top-level key becomes an output variable for downstream nodes.
A string	Wrapped under a single `script_output` variable.
A throw	Treated as a failure.

What happens when the script fails

The picker beside the Script field has two settings.

Fall back to AI

The failure context joins the model’s turn. The workflow recovers and finishes the task from the instructions.

Cancel

The execution cancels at once with the reason script_failed. No model call. This also fires when the script file is missing.

Choose Fall back to AI while a script is new. Choose Cancel for a step where a wrong action costs money — a payment, a submission, a deletion.

Pass data into a script

Data that changes per execution reaches the script as args. Declare an input schema on the node, then read each input by name.

/**
 * @param {object} args
 * @param {string} args.patient_name - Patient to file the note against.
 * @param {string} args.date_of_birth - Date of birth, as shown in the EHR.
 */
module.exports = async ({ page, args }) => {
  await page.fill('#username', '##USERNAME##');
  await page.fill('#password', '##PASSWORD##');
  await page.click('button[type="submit"]');

  await page.fill('#patient-name', args.patient_name);
  await page.fill('#dob', args.date_of_birth);
  await page.click('#save');

  return { saved: true };
};

A scripted node that declares an input schema must use the async ({ page, args }) => { ... } signature. The plain async (page) => { ... } form fails validation. Tell Astro which values change per execution and it declares the schema and wires the args for you.

Write a JSDoc @param block for every argument. The workflow sees that JSDoc when a script fails and the node falls back. It is the only description of the arguments the workflow gets.

The values themselves come from the inputs your code sends on the execute call.

Credentials in a script

##CREDENTIAL## tokens are replaced at the tool boundary, straight from the credential store. They never pass through the model.

await page.fill('#username', '##USERNAME##');
await page.fill('#password', '##PASSWORD##');

Store the values on the Agent profile.

Improve your workflows

The rest of the ways to make a workflow faster

Nodes

Where a script lives, and the rest of a node’s settings

Agent profiles

Store the credentials a script fills in

Test, iterate, publish

Ship the scripted node

Start here

Build workflows

Integrate

Operate

Concepts

Healthcare workflow automation

SDKs

What's new

Support and security

Let Astro script it

Pick the right node

Add a script

What happens when the script runs

What the script returns

What happens when the script fails

Fall back to AI

Cancel

Pass data into a script

Credentials in a script

Next

Improve your workflows

Nodes

Agent profiles

Test, iterate, publish

Let Astro script it

​Pick the right node

​Add a script

​What happens when the script runs

​What the script returns

​What happens when the script fails

Fall back to AI

Cancel

​Pass data into a script

​Credentials in a script

​Next

Improve your workflows

Nodes

Agent profiles

Test, iterate, publish

Pick the right node

Add a script

What happens when the script runs

What the script returns

What happens when the script fails

Pass data into a script

Credentials in a script

Next