# Payrail Agent Fill

Canonical URL: https://agent.payrail.one/docs/components/payrailAgentFill
Markdown URL: https://agent.payrail.one/docs/components/payrailAgentFill.md
Summary: The host built-in browser analyzes the page; Payrail Agent Fill only materializes and applies exact protected values and one exact final click.
Description: Payrail Agent Fill is a deliberately dumb actuator for exact protected form targets.

## Canonical Answer

The host built-in browser analyzes the page; Payrail Agent Fill only materializes and applies exact protected values and one exact final click. Payrail Agent Fill is a deliberately dumb actuator for exact protected form targets. Resolves exact value-free targets before protected materialization.

![Host browser to Payrail Agent Fill contract](https://agent.payrail.one/docs-assets/images/components-payrail-agent-fill-handoff.svg)

## Key Points

- No navigation, observation, page analysis, search, or challenge handling.
- Resolves exact value-free targets before protected materialization.
- Returns only target identifiers and opaque receipts.
- Works behind thin Codex, Claude, OpenClaw, Hermes, and future host adapters.

## One Page-Control Owner

The current agent runtime built-in browser owns navigation, observation, form analysis, ordinary values, exact target selection, and result interpretation. Payrail Agent Fill never starts or controls a browser.

## Exact Protected Actuation

The host browser supplies one stable document identity and closed exact target contracts. Payrail Agent Fill resolves every target first, then materializes and applies approved protected values without exposing them to the host agent.

```ts
const { fillResolvedTargets } = await import('./scripts/payrail-agent-fill-browser.mjs');

const result = await fillResolvedTargets({
  actuator: hostActuator,
  page,
  fields: resolvedProtectedFields,
});
```

## Value-Free Receipts

Fill and click results contain target identifiers, status, and opaque authority only. The host browser observes the page again and decides what the result means.

## Generic Host Contract

Codex App has the concrete acceptance adapter. Claude, OpenClaw, Hermes, and future hosts implement the same narrow actuator interface and become supported only after passing the real form matrix.

## Related

- E2E Purchase Flow: https://agent.payrail.one/docs/guides/e2e-purchase
- Agent Skills: https://agent.payrail.one/docs/integrations/agent-skills
- Payrail Agent Memory fill: https://agent.payrail.one/docs/components/memory-fill