/share html generates output file without .html extension

[paulgoodsonMSFT]

Describe the bug

When using /share html session, the command generates an HTML file in the current working directory, but the output
file is named session with no file extension. The file content is valid HTML (...), but without the .html extension,
the OS does not recognize it as an HTML file and it cannot be opened in a browser by double-clicking.

Affected version

GitHub Copilot CLI 1.0.23

Steps to reproduce the behavior

1. Run copilot to start a CLI session
2. Have a conversation to generate session content
3. Type /share html session
4. Observe the generated file at C:\Users\user_account\session
5. Note the file has no .html extension

Expected behavior

The output file should be named session.html (with the .html extension) so the operating system recognizes it as
an HTML file and it can be opened directly in a browser.

Additional context

• Operating system: Windows
• Terminal emulator: Windows Terminal
• The file content is valid HTML (starts with ), confirming only the file naming is affected
• File size: ~96 KB