Which agents remember anything between sessions?

Not surveyed yet. No implementation of this capability has been read from source, so there is no comparison to show — only the list of what is on file, below. The dimensions worth comparing are decided by reading the implementations, not before.

Present but not verified. 5 tools, registered by 4 harnesses, have not been read from source: Grok Build memory_get, Grok Build memory_search, Hermes memory, MiMo Code memory, Qwen Code save_memory.