[BUG] Using the wrong year when writing files

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When Claude Code writes plans as a markdown file, it uses the wrong year.

I create a new plan. It is January, 23rd 2026. The file name of the new plan is 2025-01-23

What Should Happen?

Expected
The file name of the new plan is 2026-01-23

Error Messages/Logs

Steps to Reproduce

Ask Cursor to write a plan for an issue. look at the directory docs/plans and check the files

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.17

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

iTerm2

Additional Information

_No response_