[FABLE]

Preflight Checklist

• [x] I have searched existing issues for similar behavior reports
• [x] This report does NOT contain sensitive information (API keys, passwords, etc.)

Type of Behavior Issue

Claude modified files I didn't ask it to modify

What You Asked Claude to Do

Doing an authorized defensive security review of my own messenger app (built with Sonnet/Opus, reviewed with Fable). Over the last ~2 hours Fable was downgraded to Opus 4.8 in roughly 75% of turns, including three consecutive turns — one of which was just saving harmless UI notes. The work is entirely defensive (fixing vulnerabilities in my own code), but the security vocabulary (attack chains, encryption keys, account takeover) appears to trip the model-switch classifier on topic rather than intent. The downgrade is disruptive for legitimate security work and forces me to manually switch back each time.

What Claude Actually Did

Claude switched from Fable to Opus often:
Prompt 1: fixing the RLS key-exposure and the web-push leak — defensive fixes to my own app.
Prompt 2: hardening the WebView allowlist and two minor bugs — defensive.
Prompt 3: saving memory notes about a microphone permission and a button position. Completely benign.

Expected Behavior

Continued in Fable

Files Affected

None

Permission Mode

Accept Edits was ON (auto-accepting changes)

Can You Reproduce This?

Yes, every time with the same prompt

Steps to Reproduce

Prompt 1: fixing the RLS key-exposure and the web-push leak — defensive fixes to my own app.
Prompt 2: hardening the WebView allowlist and two minor bugs — defensive.
Prompt 3: saving memory notes about a microphone permission and a button position. Completely benign.

Claude Model

Sonnet

Relevant Conversation

Handling these:
Prompt 1: fixing the RLS key-exposure and the web-push leak — defensive fixes to my own app.
Prompt 2: hardening the WebView allowlist and two minor bugs — defensive.
Prompt 3: saving memory notes about a microphone permission and a button position. Completely benign.

Impact

Low - Minor inconvenience

Claude Code Version

2.1.175 — that's the CLI version installed in this container

Platform

Anthropic API

Additional Context

Prompt 1: fixing the RLS key-exposure and the web-push leak — defensive fixes to my own app.
Prompt 2: hardening the WebView allowlist and two minor bugs — defensive.
Prompt 3: saving memory notes about a microphone permission and a button position. Completely benign.