Web Viewer

Real-time monitoring of agent execution

The Web Viewer provides live observability into agent execution, showing screenshots, tool calls, and LLM interactions as they happen.

Launching the Viewer

Start any task with --watch:

helios tasks/explore-desktop --watch

Then open your browser to:

http://localhost:8080

What You Can See

Live Desktop View

Real-time VNC streaming of the desktop (GUI tasks)

Screenshots

Step-by-step screenshots of agent progress

Tool Calls

Every bash command, editor action, and computer interaction

LLM Messages

Agent reasoning and responses from the model

Cost Tracking

Real-time cost monitoring with token counts and per-request costs

Viewer Interface

The viewer is organized into panels:

Desktop/Screenshot Panel

• GUI tasks: Live VNC view of the desktop, updated in real-time
• Headless tasks: Latest screenshot (if any)

Traces Panel

Shows the chronological trace of:

• Agent messages and reasoning
• Tool calls with parameters
• Tool results and outputs
• Verification status

LLM Panel

Real-time monitoring of API calls:

• Per-request costs and token usage
• Running total cost in the panel header
• Input/output/cached token breakdown
• Time to first token (TTFT) metrics
• Request/response previews

Status Bar

• Current task name
• Model being used
• Elapsed time
• Pass/Fail status

VNC Interaction

For GUI tasks, you can interact with the VNC view:

Action	Description
View only	Watch the agent work
Click	Not recommended during execution

Manual interaction during agent execution can interfere with the agent’s actions. Use view-only mode when watching live runs.

Example Session

Starting a GUI task with the viewer:

helios tasks/explore-desktop --watch

Output:

Task: explore-desktop
Model: gemini/gemini-2.5-computer-use-preview-10-2025
Provider: docker

Starting web viewer...
→ Open http://localhost:8080

[Container] Starting cua-desktop...
[VNC] Desktop ready on :5900
[Agent] Taking initial screenshot...

The viewer then shows:

1. Initial desktop screenshot
2. Agent’s plan to explore
3. Mouse movements and clicks
4. Application interactions
5. Final result

Cloud Viewer URLs

When using Daytona cloud provider, the viewer URL is a cloud-hosted preview:

helios tasks/gui-task --watch --provider daytona

Output:

Viewer: https://preview.daytona.io/sandbox-abc123/6080?token=xyz789

This URL can be shared with others to view the same session.

Custom Port

If port 8080 is already in use, specify a different port:

helios tasks/my-task --watch --port 3000

Then open:

http://localhost:3000

Troubleshooting

Port already in use

Use the --port flag to specify a different port:

helios tasks/my-task --watch --port 3000

Or find and stop the conflicting process:

# Find what's using the port
lsof -i :8080

# Kill the process
kill -9 <PID>

Viewer shows blank screen

The container might still be starting. Wait for “Desktop ready” message:

[VNC] Desktop ready on :5900

VNC not updating

This can happen with slow network connections. Try refreshing the browser or using a wired connection.

No screenshots in headless mode

Headless tasks don’t generate continuous screenshots. You’ll see tool calls and text output instead.

Without Web Viewer

If you don’t need real-time viewing:

# Run without --watch
helios tasks/my-task

# Screenshots are still saved to output directory
ls output/my-task/screenshots/

Next Steps

Running Tasks

CLI execution options

Batch Execution

Run multiple tasks in parallel