The salvaged retention check compared the built-in memory snapshot
before vs after the disk reload. That holds for a long-lived CLI agent,
but on fresh-agent surfaces (gateway per-turn agents, TUI) the cached
prompt is restored from the session DB and can predate mid-session
memory writes that the fresh MemoryStore already absorbed at init: the
snapshot is then identical on both sides of the reload while the prompt
itself is stale, so compression would retain (and re-persist via
update_system_prompt) a prompt missing the new memory for the life of
the session.
Replace the equality check with a containment check
(_cached_prompt_reflects_builtin_memory): retain the cached prompt only
when the freshly-reloaded rendered blocks appear verbatim inside it,
and rebuild when a leftover block header remains for a target whose
entries have since been emptied or disabled. Block headers are shared
via MEMORY_BLOCK_HEADERS in tools/memory_tool.py so the check stays in
lockstep with MemoryStore._render_block.
Adds regression guards for the gateway stale-restore path and the
emptied-memory leftover-block path; verified with a real-MemoryStore
E2E matrix (9 scenarios) against a temp HERMES_HOME.
kshitijk4poor
86e603e7d6