[BUG] /buddy rarity/species changed unexpectedly after update — possible salt or identity mismatch between versions

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?

After updating Claude Code, the /buddy companion changed species and rarity unexpectedly. I initially had a Rare Turtle named "Etcher" on my MacBook, but after updating to v2.1.90, the buddy changed to a Common Snail named "Gritwell" — both on macOS and Ubuntu.

The /buddy feature is supposed to be deterministic: the same Anthropic account should always produce the same buddy via accountUuid + salt → hash → species/rarity. However, the buddy changed after updating, which suggests the salt or identity input changed between versions.

What Should Happen?

Since the /buddy system is deterministic (accountUuid + salt → hash → species/rarity), the same Anthropic account should always produce the same buddy regardless of device, OS, or Claude Code version. The buddy should remain a Rare Turtle named "Etcher" after updating, not change to a different species/rarity.

Error Messages/Logs

Steps to Reproduce

1. On macOS, run an earlier version of Claude Code and open /buddy → buddy shows as Rare Turtle ("Etcher")
2. 2. Install Claude Code v2.1.90 on Ubuntu Linux, run /buddy → buddy shows as Common Snail ("Gritwell")
3. 3. Update Claude Code on macOS to v2.1.90, run /buddy → buddy now also shows as Common Snail ("Gritwell") — Rare Turtle is gone

Both machines use the same Anthropic account.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Unknown (pre-2.1.90)

Claude Code Version

2.1.90

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

Account type: Pro/Team

Previous buddy: Rare Turtle — "Etcher" (★★★ RARE) — appeared on macOS with an earlier Claude Code version

Current buddy: Common Snail — "Gritwell" (★ COMMON) — appeared after updating to v2.1.90, on both macOS and Ubuntu

Suspected cause: The salt used to hash the identity likely changed between versions (e.g., from friend-2026-401 to a different value), or the identity input changed from accountUuid to userID for Team/Pro accounts.

Reproduction is also reproducible on Ubuntu Linux (v2.1.90) — same account, same wrong buddy.

Screenshots attached showing both buddies (Rare Turtle and Common Snail).

<img width="441" height="624" alt="Image" src="https://github.com/user-attachments/assets/edbb8757-6b4b-46cf-b3db-79bd83a58348" />
<img width="714" height="1052" alt="Image" src="https://github.com/user-attachments/assets/42b0c5ff-bf90-4eb7-8069-f3ce6774c2c5" />