feat(browser): add sensitive action controls and read-only noise reduction

[cynthialong0-0]

Summary

This PR implements two tiers of sensitive action controls for the browser agent: hard blocks (always enforced) and
policy-based confirmations (enforced even in YOLO mode). It also adds explicit ALLOW rules for read-only browser
tools to reduce confirmation noise in the default approval mode.

Details

• New Settings: Added confirmSensitiveActions and blockFileUploads to agents.browser configuration in config.ts and settingsSchema.ts.
• Hard Block: Implemented a pre-invocation check for upload_file in McpToolInvocation.
• Policy-based Confirmation: Registered priority 999 ASK_USER rules for upload_file, evaluate_script, fill, and fill_form (when configured) in browserAgentFactory.ts.
• Added ALLOW rules for readonly tools in browserAgentFactory.ts.
• Update policy engine to check mcp tools against rule

Related Issues

related #15963 part 2

How to Validate

1. Enable the browser agent with confirmSensitiveActions on:

  "agents": {
    "overrides": {
      "browser_agent": { "enabled": true }
    },
    "browser": {
      "allowedDomains": ["*.com", "*.edu"],
      "blockFileUploads": true
      "confirmSensitiveActions": true
    }
  }

2. Bring up the browser agent

Test the upload file behavior by turning blockFileUploads on/off with the following prompt in YOLO mode

Go to the sample file upload form in https://cgi-lib.berkeley.edu/ex/fup.html and upload a readme file

Test other sensitive actions by turning confirmSensitiveActions on/off with prompts like:

Use evaluate_script tool to go to google.com

3. Verify sensitive tools ask users properly and readonly tools bypass the confirmation check.

Pre-Merge Checklist

• Updated relevant documentation and README (if needed)
• Added/updated tests (if needed)
• Noted breaking changes (if any)
• Validated on required platforms/methods:
  • MacOS
    • npm run
    • npx
    • Docker
    • Podman
    • Seatbelt
  • Windows
    • npm run
    • npx
    • Docker
  • Linux
    • npm run
    • npx
    • Docker

[gemini-cli]

Hi @cynthialong0-0, thank you so much for your contribution to Gemini CLI! We really appreciate the time and effort you've put into this.

We're making some updates to our contribution process to improve how we track and review changes. Please take a moment to review our recent discussion post: Improving Our Contribution Process & Introducing New Guidelines.

Key Update: Starting January 26, 2026, the Gemini CLI project will require all pull requests to be associated with an existing issue. Any pull requests not linked to an issue by that date will be automatically closed.

Thank you for your understanding and for being a part of our community!

[github-actions]

Size Change: +3.6 kB (+0.01%)

Total Size: 26.3 MB

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./bundle/devtoolsService-7BGWANK4.js	0 B	-27.7 kB (removed)	🏆
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./bundle/chunk-AWF6S5OT.js	13.6 MB	+13.6 MB (new file)	🆕
./bundle/chunk-KFWFXZX7.js	3.64 MB	+3.64 MB (new file)	🆕
./bundle/core-I6KUXQLP.js	41.8 kB	+41.8 kB (new file)	🆕
./bundle/devtoolsService-G3GIVEHR.js	27.7 kB	+27.7 kB (new file)	🆕
./bundle/interactiveCli-SAKT5JK5.js	1.61 MB	+1.61 MB (new file)	🆕
./bundle/oauth2-provider-OJAQJT3Y.js	9.19 kB	+9.19 kB (new file)	🆕

ℹ️ View Unchanged

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[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the security and user control capabilities of the browser agent by introducing granular controls over sensitive actions. It allows administrators to enforce hard blocks on file uploads and require explicit user confirmation for potentially risky operations, even in 'YOLO' mode. Concurrently, it streamlines the user experience by automatically allowing safe, read-only browser actions, thereby reducing unnecessary prompts and improving workflow efficiency.

Highlights

• Sensitive Action Controls: Implemented two tiers of sensitive action controls for the browser agent: hard blocks for file uploads and policy-based confirmations for other sensitive actions like evaluate_script, fill, and fill_form.
• Read-Only Noise Reduction: Added explicit ALLOW rules for read-only browser tools such as take_snapshot, take_screenshot, list_pages, and list_network_requests to reduce confirmation noise in the default approval mode.
• New Configuration Settings: Introduced confirmSensitiveActions and blockFileUploads settings under agents.browser to control these new behaviors, with corresponding updates to documentation and schema.

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[gemini-code-assist]

Code Review

This pull request effectively implements two tiers of sensitive action controls for the browser agent: hard blocks and policy-based confirmations, along with noise reduction for read-only browser tools. While the changes introduce important security controls, one high-severity issue was identified that requires attention. A logic flaw in browserAgentFactory.ts causes duplicate policy rules to be registered on every invocation, leading to resource exhaustion and performance degradation.

[gsquared94]

LGTM!