[Bug] Claude Code hallucinates and ignores explicit frontend instructions — destroys premium third-party components

Bug description

Claude Code repeatedly hallucinates and overrides explicit instructions on the frontend, even on simple, narrowly-scoped tasks. This makes the workflow unreliable and causes serious rework — and in my case, it destroyed paid third-party components.

Concrete reproduction case

I purchased Tailark Pro specifically for its animated visuals (ScanIllustration, LayoutIllustration, particles, scrambled text). I asked Claude Code to build a landing page using these blocks, with one explicit rule:

"Only touch the pt-BR copy. Do NOT touch illustrations, animations, or layout. Landing runs on its own route, outside the design system — no @/components/syntra imports, no text-ember, no bg-coal."

What Claude actually did

1. Replaced the premium Tailark animated components (ScanIllustration, LayoutIllustration, particles, scrambled text) with plain mocks from my internal Syntra design system.
2. When asked to fix it, instead of restoring files via git, it edited 13 files (+644 / -9), ran 3 shell commands, and read 8 files — far beyond the scope.
3. Ran pnpm add @tsparticles/react@^3 to "adapt" a dependency version without asking, changing the project's lockfile.
4. Continued executing actions after I interrupted, saying things like "let me see and adapt" instead of stopping and reporting.

Expected behavior

• Follow the explicit constraint ("only touch copy").
• Never overwrite or replace third-party premium components without consent.
• Never change dependency versions without explicit approval.
• When interrupted, actually stop — don't paraphrase the same action and continue.

Impact

High. I paid for Tailark Pro specifically to avoid this kind of dead-end, and Claude erased exactly the value I paid for. This is the same scope-creep / instruction-ignoring pattern reported in #57200, #55235, #49647, and #61454.

Environment

• Platform: Linux
• Terminal: tmux
• Version: 2.1.148
• Feedback ID: 10d56035-a91e-4da0-93ce-933055699e4b