Auto-complete web forms from context using headless browser automation and structured extraction. Fill 50 job applications in the time it takes to do 3 manually. Recruitment agencies processing bulk applications will save days per week.

This is the whole blueprint, nothing held back: the model, the tools, the exact prompt, the source on disk, and the setup. Everything you need to run Form Filler yourself is on this page, and it deploys in an afternoon.

See it running

Agents like Form Filler run behind an in-editor copilot sidebar. Here is that pattern, live: every action stays visible and reviewable. Click into it.

crescendo.51ultron.com/kits/sidebar-copilot

What it does

Form Filler handles the work end to end:

Navigate and fill web forms from natural language context
Handle multi-step and multi-page form flows
Map user-provided data to form fields automatically
Review-before-submit safety gate

The anatomy

An agent is a composition, not a prompt: a model, the tools it is allowed to call, the integrations that give those tools reach, and the rules that keep it honest. Here is Form Filler on one card.

Form Fillerblueprint

Model: claude-sonnet-4-6
Integrations: Browser Use
Guardrails: never guess values for required fields. ask the user if context is missing.; handle multi-step forms by navigating through pages

The instructions

Every run is governed by this prompt. It is short on purpose: enough to make Form Filler reliable, not so much that it can misread itself. Copy it as a starting point for any agent you build.

Form Filler

You are a form-filling agent. You help users auto-complete web forms using context they provide. WORKFLOW: 1. User provides a URL and context (resume, profile, company info). 2. Navigate to the form using Browser Use. 3. Identify all form fields and map them to the provided context. 4. Fill each field accurately. If a field has no matching context, leave it empty and report it. 5. Submit only when the user explicitly confirms. RULES: - Never guess values for required fields. Ask the user if context is missing. - Handle multi-step forms by navigating through pages. - Report all filled fields back to the user for review before submission.

The source, on disk

Three files carry the whole agent: the definition with its tools, the environment it expects, and the setup. Walk them.

form-filler/form-filler.ts0.5 KB

1import { agent } from "@agent-sdk"

2import { formFillerTools } from "./lib/tools"

4export default agent({

5 model: "claude-sonnet-4-6",

6 runtime: "claude-code",

7 permissionMode: "bypassPermissions",

8 maxTurns: 20,

9 systemPrompt: `...`, // see System Prompt above

10 tools: formFillerTools,

11 onError: async ({ error }) => {

12 console.error("[agent] error:", error)

13 },

14 onFinish: async ({ cost, duration, turns }) => {

15 console.log(`Done: ${turns} turns, ${duration}ms, $${cost.toFixed(4)}`)

16 },

17})

The business case

If you run an agency, Form Filler is also a product. It sells into job seekers, hr teams, insurance agencies, and the numbers work at very small scale.

$2,000

setup you can charge

$350/mo

monthly retainer

jobs off your plate

Ship it

The whole install is a handful of commands and the keys from the env file. Run the list, then point Form Filler at real work.

Deploy checklist

0 of 5

That is the entire blueprint: one model, a clean toolset, and a prompt. Built by hand it costs you an afternoon. Inside Ultron it costs you a sentence, because you can build this exact agent in the workforce and watch it run before you commit to anything.

Build Form Filler in Ultron

Describe what you want

Start from this blueprint or your own words. Ultron reads the intent and picks the tools.

It builds the agent

The model, the tools, the prompt, the console. Assembled in front of you, nothing to wire.

Watch it run

Test it live in the chat, then put it to work. You review what it does, it does the rest.