Lexicon

The words of AI memory, defined.

This page defines every word the site uses for AI memory. On the other pages, a term underlined with dots links here. Hover it for the short definition, click it to open its entry.

Cartridge: A cartridge is an app that runs inside Mnemosyne OS. It uses the memory as its back-end, through the SDK and under FGAC. It runs sandboxed, and it ships signed, so you know who built what you install. You publish a cartridge on MnemoHub, or keep it private.
Chronicle: A chronicle is one remembered thing. It holds the content itself and a spine type that says what kind of memory it is. A vector travels with it, so the engine can find it by meaning. Everything Mnemosyne OS knows about you is made of chronicles, and each one can be retrieved on its own.
Dream State: The OS consolidates at night, the way a brain does during sleep. It re-reads recent memory and connects it to older chronicles. It then writes dream chronicles, summaries that are deliberately weak, dated and fading. They are kept in their own vault. Everything happens on your machine, and a dream never overwrites a real memory.
Embedding (vector): An embedding is a piece of text turned into a vector, a long list of numbers. Those numbers place the text in a semantic space. Two texts that mean the same thing land close together, even with no word in common. Every chronicle gets an embedding. That is why you can ask for an idea and get the memory, not only a keyword match.
Engramm: The Mnemosyne OS license is an Engramm, a durable title of ownership recorded on the Base chain. It is yours, and you can transfer it. The name comes from the engram, the physical trace a memory leaves in the brain. You buy the license once and it does not expire.
FGAC: Fine-Grained Access Control decides who reads and writes what. A cartridge receives an explicit scope, this vault and this right, never blanket access. That contract keeps the ecosystem safe. Building on Mnemosyne OS does not open your memory.
Local-first: Local-first software works on your machine first. Your data is born there, stored there, and stays readable without a connection. You can add cloud services on top, a remote model for instance. You never need one to own or read your memory.
LongMemEval: LongMemEval is an academic benchmark. It tests whether a system really remembers across many sessions. A fact is told once, updated later, and the sessions are spread over months. On 48 questions it had never seen, Mnemosyne OS scores 77.1% under the official LongMemEval judge. On the 48 questions used to tune it, it scores 85.4% under a strict judge. The protocol was published before the run, and a question counts only when two passes both get it right. Every answer and every verdict are published, so anyone can audit them.
MCP: MCP (Model Context Protocol) is an open standard. It lets AI agents use tools and read context the same way everywhere. Mnemosyne OS ships an MCP server (@mnemosyne_os/mcp). Your coding agents and assistants can query the vault, see resonances and read git context. The same FGAC rules apply to them as to everything else.
Neural Map: The Neural Map shows your memory as a navigable space of topologies. Where a memory sits comes from its real place in the semantic space. The map never moves it to please the eye. You see what your memory actually looks like.
Off-chain signature (EIP-191): The MnemoHub catalog and its submissions are signed with a sovereign wallet key (EIP-191). Nothing is written on-chain. The signature travels inside the data itself, and any client can check who signed it. The chain serves as a source of authority, not as a database. The proof costs no gas, adds no latency and publishes nothing.
Open-core: Open-core splits the product in two. Everything a developer needs is public and MIT-licensed: the SDK, the contracts, the CLI and the scaffolder. The memory engine itself ships sealed inside the app. You build on an open, stable surface, and the engine stays on the user's machine with their memory.
RAG: RAG (Retrieval-Augmented Generation) makes a model answer from your memory instead of its imagination. The engine first retrieves the chronicles that match your question. The model then writes its answer from those chronicles. A model without retrieval can only guess. With the chronicles in hand, it cites your actual past.
Resonance: A resonance is a link the engine perceives between two chronicles that echo each other, across time or across domains. Mnemosyne OS shows you those links and never acts on them for you. The principle holds everywhere: memory perceives, situates and reveals, and the human governs.
SDK: Developers build on Mnemosyne OS with the SDK (@mnemosyne_os/sdk, MIT). ingest() writes into the vault, query() and ask() read by meaning, all under FGAC, over WebSocket or IPC. You provision no database and wire no auth, because the memory is the back-end.
Sovereignty: Sovereignty means you hold the keys, the data and the decisions. They cover the encryption, the identity and the license. The data sits on your machine. You decide what enters a vault, what leaves it, what mixes and what gets erased. Mnemosyne OS provides the engine and owns nothing of your life.
Spine: Every chronicle carries a spine type. The type says what kind of memory it is: technical knowledge, a decision, a fact about you, a dream, and so on. The engine uses it to filter, and to place a memory at the right level. Without it, the engine would see nothing but undifferentiated text.
Vault: Your memory is split into vaults, one isolated store per domain: code, research, journal, social. Each vault carries its own protection and its own rules about mixing. Crossing two vaults is a decision you make, and the app never does it on its own.
Zero-Trust IPC: IPC (inter-process communication) is how the parts of the app talk to each other. Zero-Trust means none of those messages is trusted by default, even locally. Every request carries a signed token limited to one scope, and gets checked before it touches memory. A component that is compromised, or simply curious, still reads nothing beyond its grant.