LCM-X
Lossless memory for long sessions: LCM-X keeps every turn in a local store instead of compacting it away, and the agent can search and expand it. The store is local SQLite (lcm.db) with a recoverable DAG of summaries over it and 15 lcm_* tools for search, recall and expansion. Select it with context.engine: lcm-x. Upgrading from hermes-lcm (breaking in v0.24.0): stop Hermes, then in plugins.enabled replace hermes-lcm with hermes-lcm-x and run exactly one LCM copy (the install script prints the steps; the old engine name lcm still resolves with a deprecation warning); lcm.db and the lcm: config block are unchanged. Summaries use the model Hermes is configured with.
Good to know before installing
Optional semantic recall (embeddings_enabled, off by default) sends message text to the embedding provider you configure (Voyage via VOYAGE_API_KEY, an OpenAI-compatible endpoint, or a local Ollama), and once enabled new summaries are embedded automatically in the background; in-process FastEmbed keeps it on the machine after a one-time model download. For known cloud providers the provider-bound copy is privacy-transformed by default (LCM_EMBEDDING_PRIVACY_ENABLED=false opts out), while lcm.db keeps the raw text. Every turn (user, assistant and tool output) is stored in plaintext in lcm.db (secret redaction at rest is opt-in), and oversized tool outputs are by default written as plaintext files under HERMES_HOME/lcm-large-outputs and replaced in the model's context by recoverable references. The engine also reads Hermes' state.db read-only for session lineage, reads private AIAgent attributes via the call stack on Hermes builds without subagent hooks, and runs git on its own install directory for lcm_status/lcm_doctor; tiktoken may fetch its BPE file on first use.
From the plugin's catalog listing.
How to install
- Install it. Hermes asks for any API keys it needs, then asks whether to turn it on.
hermes plugins install hermes-lcm-x - Said no? Turn it on later:
hermes plugins enable hermes-lcm-x - Restart Hermes so it loads the plugin.
Some plugins also need a sign-in or settings: see Full setup & settings. Memory plugins ask whether to become your memory provider instead. Steps follow the official plugins guide (opens in a new tab).
- Category
- Memory & notes
- Maintained by
- 100yenadmin (Community)
- Needs
- No API keys declared
- Adds tools
lcm_greplcm_recalllcm_query_statelcm_computelcm_compile_evidencelcm_evidence_packlcm_retrievelcm_recentlcm_load_sessionlcm_describelcm_expandlcm_expand_querylcm_statuslcm_inspectlcm_doctor- Needs Hermes
- 0.21.3 or newer
- Version
- 0.28.1
- In the catalog
- 2026-09-26, updated 2026-10-25
- GitHub stars
- 109
Full setup & settings ↗Source code ↗
More in memory & notes
New Hermes Agent updates every day on X. Follow @HermesWatcher