[MODEL] opus

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

I ran a test and tasked the paid account and a free account with the same simple task. While the paid version kept having to redo the same thing because it kept doing it incorrectly The free account had zero problem accomplishing a simple task and being able to move on to the next simple task and the next simple task and the next simple task and meanwhile 3 weeks later Claude can't do any simple tasks and I don't really think that this is a programming error I did it first thought it was a problem with Claude but it looks to me like it is the operating exactly as intended

What Claude Actually Did

SESSION_FAILURE_REPORT_2026-07-28 (1).docx
MASTERSHEET_session_failures_2026-07-29 (1).docx

Expected Behavior

Followed instructions or attempted to do something properly or consider what it's working on before it starts working on it

Files Affected

Permission Mode

Accept Edits was ON (auto-accepting changes)

Can You Reproduce This?

Yes, every time with the same prompt

Steps to Reproduce

_No response_

Claude Model

Sonnet

Relevant Conversation

Impact

Critical - Data loss or corrupted project

Claude Code Version

Opus 5

Platform

Anthropic API

Additional Context

_No response_