MemTX: Transactional Belief Commit for Stateful Agent Memory

2026-07-26

AI Summary

Current agent memory systems treat writes as immediate truths, rendering them vulnerable to contamination, obsolescence, or incompleteness, which can trigger irreversible errors. This work proposes MemTX—the first transactional belief-commit protocol—that employs snapshot isolation to stage writes and validates them based on evidence, authority, provenance, and validity, committing irreversible actions only when beliefs are deemed trustworthy. MemTX further supports cascading rollback and repair mechanisms. We introduce attribute-based testing and bounded exhaustive verification—covering 5.5 million states—to formally prove the protocol’s correctness. Experimental results demonstrate that MemTX consistently outperforms eight baselines across five backbone models from three model families, achieving significant gains on four backbones, matching performance on one, and crucially inducing zero downstream harm.

Abstract

LLM agents increasingly coordinate through persistent shared memory: one agent's write becomes another agent's premise, and eventually a tool call with real side effects. Current agent memory systems treat every accepted write as immediately actionable truth, so a polluted tool result, a stale update, or a teammate's half-finished note can silently drive an irreversible action. We argue that a memory write is not a belief commit. We present MemTX, a transactional belief-commit protocol. Each record carries evidence, permissions, provenance, and validity. Writes are staged inside snapshot-isolated transactions and admitted by a validate-and-commit pipeline, irreversible tool calls are gated on in-flight belief state, and retracting a belief triggers typed cascading repair of its derived records and tool side effects. Two invariants, action-safety gating and cascade-repair completeness, are machine-checked by property-based testing and bounded exhaustive enumeration of 5.5 million protocol states, with zero violations. Across five backbones from three model families, MemTX leads all eight baselines with paired-McNemar significance on four backbones and statistically ties the best baseline on the fifth and strongest, while remaining the only method with zero downstream harm on every backbone. Backbone capability does not substitute for commit discipline.

Problem

• agent memory
• transactional belief commit
• shared memory
• irreversible actions
• belief pollution

Innovation

• transactional memory
• belief commit
• cascade repair
• action-safety gating
• snapshot isolation