StateLedger: Path-Addressed External Memory for Persistent Multi-Agent Systems

Persistent LLM agents need memory that preserves state, provenance, validity, and evidence across long interaction histories. We introduce StateLedger, a path-addressed external memory substrate that stores memory as durable state evolution rather than flat retrievable items: events update canonical paths, registers absorb small changes, CommitPages record residual drift against Checkpoints, cue views bound traversal, and content-addressed artifacts avoid evidence duplication. We prove storage, retrieval, coalescing, and conflict-aware ranking guarantees under explicit coverage and reader-consistency conditions. Empirically, StateLedger improves task performance and storage efficiency across LongMemEval, LoCoMo, and Evo-Memory Multi-turn, reaching 98.8% on LongMemEval-S, 82.6% on LongMemEval-M with 14.7% durable footprint, 95.8% LoCoMo non-adversarial accuracy, 87.1% unweighted success, and 93.5% unweighted progress on Evo-Memory.