Why Agent Memory Write Policies Matter More Than Retrieval

Most agent memory tutorials focus on retrieval while ignoring the more complex write-path, which determines what information actually gets stored long-term. Without a deliberate write policy, vector stores quickly fill with low-value, transient data that degrades memory quality over time. Simple approaches like storing everything or keeping only recent observations both fail because they lack a judgment layer before writing. The recommended approach treats long-term memory like a production codebase, where observations sit in a temporary scratchpad and only pass to permanent storage through an explicit, gated promotion pipeline. Security concerns compound the problem, as misconfigured network policies or access controls can silently prevent agents from reaching their own memory stores.