Why Agentic Browsers Struggle with Complex Forms (and What Fyllyo Does Differently)
Agentic browsers like Comet, Dia, Arc, and Atlas are revolutionizing web automation. But when it comes to complex, multi-page forms, purpose-built solutions still win on accuracy, security, and speed.
Agentic browsers are one of the most exciting developments in AI-powered browsing. Tools like Comet, Dia, Arc, and Atlas promise to automate repetitive web tasks, including form filling. For many use cases, they deliver remarkably well. But when it comes to complex, multi-page forms—like visa applications, tax filings, or lengthy government forms—the limitations become apparent. Here's what works, what doesn't, and why purpose-built solutions still matter.
What Are Agentic Browsers?
Agentic browsers integrate artificial intelligence directly into your browsing experience, acting as autonomous agents that can perform tasks on your behalf. Rather than just suggesting autofill options, they can understand context, navigate pages, and complete multi-step workflows.
Example: Comet's Form Filling
Instead of manually typing your information into every signup form, you can simply command:
"Comet, fill this form using my saved details."
The browser instantly populates all fields with your stored information, keeping you in control of what gets submitted.
Where Agentic Browsers Excel
Let's start with what these tools do really well. Agentic browsers are genuinely impressive for many common scenarios:
📝 Simple Form Filling
Single-page forms with standard fields like name, email, phone number, and address. Perfect for event registrations, newsletter signups, and basic contact forms.
🔄 Repetitive Tasks
Automating the same action across multiple sites or tabs—like filling out your shipping address on different e-commerce platforms.
🗂️ Tab Management
Organizing browser tabs, managing bookmarks, and navigating between pages based on natural language commands.
🛍️ Basic Shopping Tasks
Price comparisons, adding items to cart, and navigating product categories with voice or text commands.
For these use cases, agentic browsers represent a genuine step forward in web automation. They save time, reduce friction, and make browsing more intuitive.
Where Complex Forms Become Problematic
The challenge starts when you move beyond simple forms to complex, real-world applications. Government visa forms, tax returns, lengthy job applications, and multi-page financial documents expose the limitations of general-purpose browser agents.
Multi-Page Forms with Context
Real-world example: When users tried using Comet to book flights for multiple passengers, the process was notably slow. While it eventually completed the task, maintaining context across multiple passenger entries proved challenging.
The issue compounds with forms that span 40+ pages (like UK visas or DS-160 forms), where information entered on page 3 determines what fields appear on pages 15, 23, and 37.
Dynamic Field Logic
Many government and enterprise forms use conditional logic where selecting one option reveals entirely new sections. For example, checking "Yes, I have dependents" might trigger 15 new fields about each family member, with different validation rules based on their relationship to you.
Complex forms require collaboration
Complex forms require collaboration between the user and the agent. Agents might do 99 things correct, but might mess 1. This is where a collaboration workflow results in a great user experience, compared to one time instruction agents, which will lose track of progress.
Instructions is still not one click
Complex forms will still require you to constantly instruct in plain english which is tiresome if you have 40 pages.
Real User Feedback
Users on Reddit and tech forums consistently report that agentic browsers need ultra-granular instructions for complex forms. Instead of "fill this form," they find themselves micromanaging: "fill field 1, now field 2, select this dropdown option, now click next, fill field 7..." At that point, it's faster to just fill it manually.
The Core Problem: UI-Layer Automation
Here's the technical reason why agentic browsers struggle: they drive the UI layer—clicking buttons, typing into visible fields, navigating through DOM events. This works fine for simple flows, but breaks down when:
- Agentic browsers are not that good today but I am betting they would be. They would good enough to handle any page, fields. But they still wont be a good form filling product.
- Agentic browsers should be able to handle dynamic forms, but they would be too slow.
- Forms require maintaining all your information in a structured way to make it one click fill.
- The form requires maintaining state across dozens of pages
How Fyllyo Solves This: Purpose-Built Form Automation
Fyllyo takes a fundamentally different approach. Instead of driving the UI layer, we work with structured data models that map to form field semantics. This means we understand what each field means, not just where it is on the page.
🧠 Structured Data Mapping
Fyllyo maintains a structured representation of your information with relationships and context. It knows your employer, when you worked there, and what role you had— not just strings to paste.
This enables smart inference: if a form asks for your "current employer's city," Fyllyo knows to extract that from your employment record, even if you never explicitly stated it separately.
🔄 Context Persistence
Information entered on page 3 is remembered and applied to pages 15, 23, and 37. If you indicated you're employed, Fyllyo will automatically fill employment details wherever they appear—even if they're buried in conditional sections.
⚡ Dynamic Field Handling
When selecting an option reveals new fields, Fyllyo recognizes what just appeared and fills them appropriately based on your data model—no manual intervention required.
✅ Auto-Formatting & Validation
Dates, phone numbers, postcodes—Fyllyo auto-formats to match each form's requirements. UK forms want DD/MM/YYYY? US forms need MM/DD/YYYY? Handled automatically.
📄 Document Intelligence
Upload your passport, bank statements, or employment letters. Fyllyo extracts relevant information and uses it to make smart inferences throughout the form.
🚀 Automatic Progression
Once a page is complete, Fyllyo moves to the next automatically. You maintain control—you can pause, correct mistakes, and continue at any time.
Real-World Example: UK Visa Application
The UK visa application is one of the most complex forms you'll encounter online. It's a perfect test case for form automation technology:
- 40+ pages with save-and-continue functionality
- Deep conditional logic: Every answer branches the next 5-10 screens
- Role-based data: Principal applicant vs. spouse vs. children require different sections
- Context dependencies: Information from page 3 affects pages 15, 23, and beyond
- Complex validation: Dates must be consistent, travel history must match passport stamps
Agentic browsers would struggle to maintain context across this complexity. Fyllyo handles it end-to-end. Here's a demonstration:
What You'll See in the Demo
- ✓ Maintains context across all 40+ pages
- ✓ Fills dynamic fields that appear based on your answers
- ✓ Auto-formats dates, postcodes, and other locale-specific data
- ✓ Smart inference—knows UK relatives from uploaded documents
- ✓ Automatic page progression when sections are complete
- ✓ Error correction—you can fix mistakes and keep going
When to Use Each Approach
Both agentic browsers and purpose-built form fillers have their place. Here's how to think about which tool to use:
Use Agentic Browsers For:
- ✓ Simple signup forms and registrations
- ✓ General browsing automation
- ✓ Tab management and organization
- ✓ One-off tasks with straightforward flows
- ✓ Scenarios where you can provide specific instructions
Use Fyllyo For:
- ✓ Government forms (visas, tax returns, permits)
- ✓ Multi-page applications with 10+ steps
- ✓ Forms with complex conditional logic
- ✓ Situations requiring context across pages
- ✓ When accuracy and security are critical
- ✓ PDF form filling
The Future: Hybrid Approaches
The ideal future might combine both approaches. Agentic browsers could handle navigation and simple tasks, while specialized form fillers like Fyllyo tackle complex forms. The key is recognizing that one size doesn't fit all—different problems require different tools.
For now, if you're facing complex forms that span multiple pages, require careful context management, or involve sensitive data, purpose-built solutions deliver better results. They're designed specifically for the problem, with architecture that addresses the unique challenges of form automation.
Conclusion
Agentic browsers represent an exciting evolution in web automation. Tools like Comet, Dia, Arc, and Atlas are genuinely useful for many everyday tasks. But complex form filling remains a specialized challenge that benefits from purpose-built solutions.
The difference comes down to architecture: UI-layer automation works great for simple tasks but struggles with complexity. Structured data models that understand field semantics and maintain context across pages deliver better accuracy, security, and speed for real-world forms.
Ready to Try Fyllyo?
Experience the difference purpose-built form automation makes. Whether you're applying for visas, filling tax returns, or completing job applications, Fyllyo handles the complexity so you don't have to.