[Bug] Claude 3 Opus model behavior regression: ignoring system instructions and tool constraints

Bug Description
Opus got dumber lately. Harness engineering is not even working. Opus just bypasses skills, rules and instruction. Please bring it back, Anthropic.

Environment Info

• Platform: linux
• Terminal: tmux
• Version: 2.1.96
• Feedback ID: 8c90b7bb-e406-4f1e-ab15-498f23e8ebe8

Errors

[{"error":"Error: 529 {\"type\":\"error\",\"error\":{\"type\":\"overloaded_error\",\"message\":\"Overloaded\"},\"request_id\":\"req_011CZsqm1jTQ3RAoxBgBSJxw\"}\n    at generate (/$bunfs/root/src/entrypoints/cli.js:11:51730)\n    at makeRequest (/$bunfs/root/src/entrypoints/cli.js:50:4942)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-04-09T07:57:52.510Z"},{"error":"Error: Request was aborted.\n    at sh$ (/$bunfs/root/src/entrypoints/cli.js:1243:11929)\n    at next (native:1:11)\n    at vC7 (/$bunfs/root/src/entrypoints/cli.js:7775:9035)\n    at next (native:1:11)\n    at VC7 (/$bunfs/root/src/entrypoints/cli.js:7780:11451)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-04-09T08:00:40.321Z"}]