[GH-ISSUE #138] bug: Browser tool does not support custom viewport size for screenshots #64

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opened 2026-10-18 14:02:34 +00:00 by bsakaguchi · 2 comments

bsakaguchi commented

2026-10-18 14:02:34 +00:00

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Originally created by @JKGeovision on GitHub (Jul 12, 2026).
Original GitHub issue: https://github.com/open-webui/computer/issues/138

Hello,

I discovered a limitation where the browser tool does not allow setting a custom viewport size. The browser is launched with a fixed container viewport of 780x493 pixels, and there is no configuration option to change it.

This makes it impossible to take high-resolution screenshots (e.g. 1920x1080) using the integrated browser tool. The only option is to bypass the browser tool entirely and use chromium --headless --screenshot --window-size=1920,1080 directly from the command line, which defeats the purpose of having the browser tool for interactive browsing.

Steps to reproduce:

Use the browser_navigate tool to open a website
Use the browser_screenshot tool to capture a screenshot
The resulting screenshot is only 780x493 pixels

What I tried:

browser_evaluate('window.resizeTo(1920, 1080)') — does not work in headless mode
Checked for a cptr config file (e.g. ~/.cptr/config.yaml) — none exists
No viewport_size parameter is exposed on any browser tool function

Thank you for your work, and I wish you all a great day,
Joshua Krimmer

Originally created by @JKGeovision on GitHub (Jul 12, 2026). Original GitHub issue: https://github.com/open-webui/computer/issues/138 Hello, I discovered a limitation where the browser tool does not allow setting a custom viewport size. The browser is launched with a fixed container viewport of 780x493 pixels, and there is no configuration option to change it. This makes it impossible to take high-resolution screenshots (e.g. 1920x1080) using the integrated browser tool. The only option is to bypass the browser tool entirely and use `chromium --headless --screenshot --window-size=1920,1080` directly from the command line, which defeats the purpose of having the browser tool for interactive browsing. **Steps to reproduce:** 1. Use the `browser_navigate` tool to open a website 2. Use the `browser_screenshot` tool to capture a screenshot 3. The resulting screenshot is only 780x493 pixels **What I tried:** - `browser_evaluate('window.resizeTo(1920, 1080)')` — does not work in headless mode - Checked for a cptr config file (e.g. ~/.cptr/config.yaml) — none exists - No viewport_size parameter is exposed on any browser tool function Thank you for your work, and I wish you all a great day, Joshua Krimmer

bsakaguchi closed this issue

2026-10-18 14:02:34 +00:00

bsakaguchi commented

2026-10-18 14:02:35 +00:00

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@owui-terminator[bot] commented on GitHub (Jul 12, 2026):

🔍 Related Issues Found

I found some existing issues that might be related. Please check if any of these are duplicates or contain helpful solutions:

🟢 #15 feat: computer control / computer use
This is the only issue found touching screenshot taking/browser control in this repository. It appears to be a broad request for computer/browser interaction, which is the same feature area as the viewport-size limitation.
by Classic298

💡 If your issue is a duplicate, please close it and add any additional details to the existing issue instead.

This comment was generated automatically. React with 👍 if helpful, 👎 if not.

@owui-terminator[bot] commented on GitHub (Jul 12, 2026):  🔍 **Related Issues Found** I found some existing issues that might be related. Please check if any of these are duplicates or contain helpful solutions: 1. 🟢 [#15](https://github.com/open-webui/computer/issues/15) **feat: computer control / computer use** *This is the only issue found touching screenshot taking/browser control in this repository. It appears to be a broad request for computer/browser interaction, which is the same feature area as the viewport-size limitation.* *by Classic298* --- 💡 If your issue is a duplicate, please close it and add any additional details to the existing issue instead. *This comment was generated automatically.* React with 👍 if helpful, 👎 if not.

bsakaguchi commented

2026-10-18 14:02:35 +00:00

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@tjbck commented on GitHub (Jul 16, 2026):

Should be addressed, Testing wanted here!

@tjbck commented on GitHub (Jul 16, 2026): Should be addressed, Testing wanted here!

bsakaguchi referenced this issue

2026-10-18 14:03:07 +00:00

[GH-ISSUE #201] feat: stdio MCP tool servers need an env variables field in the UI (branch with fix available) #120