My agent quietly corrupted its own memory graph, and I am trying something.

If your agent keeps a memory graph, the agent itself is writing the edges, and that is where this bit me. The LLM occasionally writes an edge that should never exist: two node types that have no business being connected, or the wrong relation. It does not error. It just sits there, and you only notice three hops later when a retrieval comes back confidently wrong. A concrete shape of it: a directed\_by style edge ends up leaving the wrong kind of node, so a later traversal follows it and tells me a person directed a genre. Structurally fine, semantically nonsense, and the model repeats it with full confidence. The idea I am testing: **declare the allowed node types and edges once, as an ontology, and check at two points**. Reject a memory write that violates it, and stop a **traversal hop that is not allowed**, naming the bad hop instead of returning the wrong node. Declared once, like: directed\_by: from Movie to Person Quick test on 120 deliberately broken traversals: the plain version was silently wrong on all 120, the checked version caught all 120 and pointed at the bad step. **I mostly want to know how people running agents in anger handle this: do you hard reject bad memory writes, or let the model self correct and clean up later?** I will drop a link to the prototype in a comment for anyone who wants to tear it apart. It is not production ready or anything.