Add screenshot persistence to panel_take_screenshot tool

[Copilot]

Screenshot Saving Feature Implementation

• Review the current take_screenshot implementation
• Add save_screenshot parameter to take_screenshot tool (default: True)
  • True: Save to .screenshots subfolder in user data directory
  • False: Don't save (returns image only to AI)
  • str (absolute path): Save to specified path
• Add screenshot directory configuration to ServerConfig in config/models.py
• Implement path validation (ensure absolute path or raise exception)
• Implement file saving logic with timestamp-based naming
• Keep return value as ImageContent only (per user request)
• Add comprehensive tests for:
  • Default save behavior (save_screenshot=True)
  • Disabled save behavior (save_screenshot=False)
  • Custom path save behavior (save_screenshot="/absolute/path/to/file.png")
  • Path validation (raise exception for relative paths)
• Update documentation
• Move imports to top of file (code review feedback)
• Run linters and tests (will run in CI)
• Request code review
• Run security scan (CodeQL)

Original prompt

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This section details on the original issue you should resolve

<issue_title>Save screenshot</issue_title>
<issue_description>When using the panel_takescreenshot tool it would be really nice if the screenshot was saved such that it can be accessed by a human.

I would need to analyze if there are more things I would like to save.

• I would suggest that screenshots are saved by default (True) to .screenshots subfolder of the data folder
• I would suggest that its possible to disable screenshot save (False)
• I would suggest its possible to provide a path as argument. The path should be absolute. If not an exception should be raised.</issue_description>

<agent_instructions>Please first review this suggestion. Please list improvements identified if any. Then make a plan for implementing this. Come back and ask me to review the plan.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes Save screenshot #119

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[MarcSkovMadsen]

Looks like a good plan. But don't change the response. Continue to return the image only as response.

Please implement

[Copilot]

Looks like a good plan. But don't change the response. Continue to return the image only as response.

Please implement

Implemented in commits bcfd181 and 5051564. The take_screenshot tool now:

• Accepts save_screenshot parameter (default: True)
  • True: Saves to ~/.holoviz-mcp/screenshots/ with timestamp-based filename
  • False: Skips saving, returns image only
  • str: Saves to specified absolute path (validates path is absolute)
• Returns only ImageContent (unchanged from original behavior)
• Logs save location when screenshots are saved
• Added comprehensive tests for all save modes and path validation

Configuration can be customized via server.screenshots_dir in config.

[MarcSkovMadsen]

Please fix any comments

[Copilot]

Please fix any comments

All comments addressed in commit 8a8251d.