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

  1. Install it. Hermes asks for any API keys it needs, then asks whether to turn it on.
    hermes plugins install hermes-lcm-x
  2. Said no? Turn it on later:
    hermes plugins enable hermes-lcm-x
  3. 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_grep lcm_recall lcm_query_state lcm_compute lcm_compile_evidence lcm_evidence_pack lcm_retrieve lcm_recent lcm_load_session lcm_describe lcm_expand lcm_expand_query lcm_status lcm_inspect lcm_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 ↗

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