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28naem-del/mnemosy-ai

v3.0.0-rc.4MIT

Mnemosyne (npm mnemosy-ai): evidence-tracked local memory over MCP. One SQLite file per Hermes profile; corrections retire the memories that depended on them.

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Mnemosyne for Hermes Agent (mnemosy-ai)

A Portable Agent Plugin that connects Hermes Agent to Mnemosyne, the npm package mnemosy-ai: an evidence-tracked local memory MCP server. Website: https://mnemosy.ai.

Which Mnemosyne is this? This package is published from 28naem-del/mnemosyne as npm mnemosy-ai. It is not the mnemosyne Hermes memory provider from mnemosyne-oss/mnemosyne (PyPI mnemosyne-memory); the two projects share a name and nothing else.

What it adds

  • One MCP server, mnemosy, started over stdio with npx -y -p mnemosy-ai@3.0.0-rc.4 mnemosy mcp. Its 16 tools appear as mcp__mnemosy__memory_* (recall, context, store, correct, checkpoint, resume, inspect and others). memory_forget is not exposed.
  • One skill, mnemosy-ai:mnemosy-memory, telling the model when to recall, store, correct and checkpoint.
  • No Python, no hooks, no automatic per-turn recall or capture.

Install

hermes plugins install mnemosy-ai --no-enable   # once listed in the catalog
hermes plugins enable mnemosy-ai

Needs Node.js >= 22.16 and npm (npx) on PATH.

The first start downloads the package with npx, which can take longer than Hermes's default 60 s MCP connect timeout, and a portable plugin cannot raise it. If the server fails to connect on first start, run npx -y -p mnemosy-ai@3.0.0-rc.4 mnemosy --help once to fill the npm cache, or use the ~/.hermes/config.yaml route with connect_timeout: 120 (see the project README).

Disclosures

  • Package download. The first start runs npx, which downloads the pinned mnemosy-ai@3.0.0-rc.4 and its dependencies from the npm registry. These include native addons (onnxruntime-node; optional sqlite-vec and hnswlib-node) that npm installs as prebuilt binaries for your platform. No binary is committed in this plugin directory.
  • Pre-release. 3.0.0-rc.4 is a release candidate on the npm next channel.
  • Local data. Memories are written to memory.sqlite in the plugin's profile-scoped data directory (${PLUGIN_DATA}), file mode 0600. Each Hermes profile gets its own database. Apart from the optional model cache below, the server reads no other host files.
  • Network. On this default configuration the server makes no network calls and sends no telemetry. Semantic recall uses a local embedding model only if you have fetched it beforehand in a separate, explicit setup step (see the project README); otherwise recall is lexical. Hermes itself may check the npm package against the OSV malware database before launching it.
  • Writes without a prompt. Store, correct, checkpoint, capture and observe calls write to the local database without asking. To require approval for every write, add a same-name mcp_servers.mnemosy entry with trust: untrusted to ~/.hermes/config.yaml.
  • No credentials. The plugin needs no API key and stores none.

Untested status

This package follows the Hermes Portable Agent Plugin format as documented for Hermes v0.22.5. The maintainers have not yet run this plugin under Hermes. In particular, it is unverified which Node.js runtime Hermes uses to start stdio MCP servers, and whether the package's native addons load under it.

License

MIT, see LICENSE.

Maintainers

At each release, bump version in plugin.json and the mnemosy-ai@<version> pin in mcp.json together; the Hermes catalog entry then needs a new commit sha.