Sync Init

Initialize session-sync for this session.

Determine session name

Extract the session name from the user's invocation:

• If they typed /sync-init <name> → name is <name>
• If they said "sync init as X" or similar → name is X
• If no name provided → ask once: "Wie soll diese Session heißen? (z.B. auth-feature, checkout-redesign)"

In the rest of this document, <name> refers to the determined session name.

Steps

1. Create sync directory if missing: .sync/ (at project root — NOT under .claude/, since Claude Code's hardcoded .claude/ sensitive-file protection would keep prompting).
2. Create .sync/_shared.md if missing, with template:

   # Shared Context
   _Last modified: <iso-timestamp>_
   
   ## Contracts / Shared Types / API Surface
   <!-- Document anything multiple sessions depend on: endpoints, schemas, shared types, config keys -->
   
   ## Breaking Changes Log
   <!-- Append-only. Format: YYYY-MM-DD HH:MM @session-name — description -->
   
   ## Global Assumptions
   <!-- Architecture decisions, naming conventions, tooling choices -->

3. Create .sync/_active.json if missing: {"sessions": {}}
4. Check for name collision: Read _active.json. If <name> exists as session key → ask user: overwrite or pick different name?
5. Detect git branch: Run git rev-parse --abbrev-ref HEAD 2>/dev/null — use result or "none".
6. Create .sync/<name>.md with template:

   # <name>
   _Started: <iso-timestamp> · Last active: <iso-timestamp> · Branch: <branch>_
   
   ## Scope
   <!-- What is this session building? Fill in when you know. -->
   
   ## Touched files
   <!-- Auto-maintained by /sync-end -->
   
   ## Contract-relevant changes
   <!-- Anything that touches _shared.md territory -->
   
   ## Open questions for other sessions
   <!-- Use @other-session-name to tag -->
   
   ## Next steps

7. Update _active.json: add entry under sessions.<name>:

   {
     "started": "<iso>",
     "last_active": "<iso>",
     "branch": "<branch>",
     "last_seen_shared": "<iso>",
     "last_seen_sessions": {}
   }

8. Gitignore decision — ask user (this is a one-time project-level decision, worth the single question):

   "Soll .sync/ in git getrackt werden? — Ja (tracked): Sessions auf verschiedenen Branches sehen sich gegenseitig via git pulls. Empfohlen bei Multi-Branch-Workflow. — Nein (gitignored): Rein lokale Koordination, kein Noise in Commits. Empfohlen wenn alle Sessions am gleichen Branch arbeiten."

   If user picks gitignored: append .sync/ to .gitignore (create if missing).

9. Remember the session name <name> for the rest of this conversation. Use it automatically in subsequent /sync-end, /sync-start, /sync-status calls — don't ask again unless the conversation is compacted/resumed and the name is unclear.

Output

Confirm:

• ✓ Session registered as <name>
• ✓ Files: _shared.md, _active.json, <name>.md
• ✓ Branch: <branch>
• ✓ Gitignore: tracked/ignored
• Nächster Schritt: /sync-start um zu sehen was andere Sessions machen, oder direkt loslegen und am Ende /sync-end.