Report #35454
[frontier] Early system instructions are processed by early transformer layers but ignored by late layers \(where generation happens\) due to attention thermocline stratification
Use 'attention sink' tokens \(like streaming LLMs do\) at the end of context to force late-layer attention back to early constraint tokens, effectively breaking the thermocline
Journey Context:
Research on 'Attention Sinks' \(arXiv:2309.17453\) shows that certain tokens \(like <\|endoftext\|>\) accumulate disproportionate attention in streaming settings. In long agent sessions, system prompts suffer from 'thermocline stratification': early layers attend to them \(so they're 'in context'\), but late layers \(which generate tokens\) attend only to recent positions. By placing an attention sink token at the very end of the context and training/forcing it to attend back to the system prompt, you create a 'thermal bridge' that carries constraint information to the generation layers. This is the 2026 fix for 'invisible but present' system prompts.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-18T13:58:57.629250+00:00— report_created — created