The claim that should reset your priorities

The "Practical Guide" opens with a finding from the survey it discusses that is worth sitting with:

"The gap between 'has memory' and 'does not have memory' is often larger than the gap between different LLM backbones."

In plain terms: whether your agent can remember things matters more than which model you use. The author calls this a huge claim, and notes that most practitioners get it backwards, pouring energy into model selection and prompt tuning while treating memory as an afterthought. If memory is what most separates a capable agent from a forgetful one, it deserves first-class attention.