checkpoint

Letter Checkpoint Skill

This skill writes a session summary to .memory/ for future context restoration.

When to Use

Invoke this skill when:

• User types /letter-checkpoint or /checkpoint
• User says "wrap up", "end session", or "exit"
• Session is about to end

Execution Steps

1. Create the .memory folder if it doesn't exist:

   mkdir -p .memory
   

2. Determine the filename using timestamp format:

   • Format: letter_YYYYMMDDHHMMSS.md (e.g., letter_20260321143022.md)
   • Use the current date and time to generate the filename
   • This ensures uniqueness without counters and enables chronological sorting

3. Write the letter using the Write tool:

   • File path: .memory/letter_YYYYMMDDHHMMSS.md
   • Content: The generated letter following the template

4. Confirm to user: Tell them the checkpoint was saved with the filename.

Letter Template

The content MUST follow this structure:

# Letter to Myself (Session Handoff)

**Date:** [Current date and time]

## 1. Executive Summary
* **Goal:** [One sentence on what we were building]
* **Current Status:** [Stopped at file X / debugging function Y]

## 2. The "Done" List (Context Anchor)
* Implemented [Feature A]
* Fixed [Bug B]
* Refactored [Component C]

## 3. The "Pain" Log (CRITICAL)
* **Tried:** [Library/Method that failed]
* **Failed:** [Error message or unexpected behavior]
* **Workaround:** [How we solved it]
* *Note:* Do not retry the failed method above.

## 4. Active Variable State
* Environment variables, ports, or temporary mock data
* Any config that was changed

## 5. Immediate Next Steps
1. [ ] Action item 1
2. [ ] Action item 2
3. [ ] Action item 3

Important Notes

• Always include the Pain Log even if empty (write "No major issues encountered")
• Be specific in the Done List - include file names and function names
• Next Steps should be actionable and specific