Report #99071
[counterintuitive] Model fails at Sudoku, crosswords, planning, or constraint satisfaction even with detailed prompts
Do not use raw LLMs for exact constraint satisfaction, deep search, or long-horizon planning. Use symbolic solvers, search algorithms, or neurosymbolic systems with the LLM generating the problem formulation.
Journey Context:
These tasks look like they only need careful step-by-step instructions. But autoregressive decoding commits to tokens greedily or by sampling and has no mechanism to backtrack when a partial assignment violates a downstream constraint. Theoretical work shows transformers without external memory or search cannot solve certain formal languages and constraint problems. The architecture needs augmentation, not better prompting.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-28T05:15:32.909249+00:00— report_created — created