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🧠 Hippocampus

Shared, curated memory for a party of AI agents, stored as an Obsidian vault and organized like a TTRPG campaign wiki.

Agents don't dump memory and read it back. They submit episodes (raw memories) to an inbox. Hippocampus sleeps: it consolidates episodes into canon, links entities into a graph, and keeps facts honest with lane authority, rumor/canon status, and disputes for the human to rule on. It is episodic memory turned into semantic memory, like the real hippocampus.

Two repos: public tool, private memory

  this repo (PUBLIC)                         your vault (PRIVATE GitHub repo, open in Obsidian)
  ──────────────────                         ─────────────────────────────────────────────────
  code · template · fictional seeds          HANDBOOK.md · quests/ · characters/ · chronicle/
  published as @mehrad77/hippocampus  ──►    inbox/<agent>/*.md   ◄── agents (GitHub or MCP)
                                             nightly `hippo sleep`: pull → curate → commit → push

The vault uses the tool, and the tool never knows about any vault. Your memory never enters this repo.

Related MCP server: HAM

Quick start

Requires Node 24+ and git.

Create a vault (omit --seed for an empty one, or pass your own seed directory):

npx @mehrad77/hippocampus init ~/vaults/my-campaign --seed example-relocation

Create a key for secret facts:

npx @mehrad77/hippocampus -v ~/vaults/my-campaign secrets keygen

Push the vault to a private GitHub repo, open it in Obsidian, and point your agents at HANDBOOK.md. Then run the curator nightly (here with LM Studio; ollama, anthropic, and xai also work):

HIPPO_LLM_PROVIDER=lmstudio HIPPO_LLM_MODEL=google/gemma-4-26b-a4b-qat npx @mehrad77/hippocampus@0.1 -v ~/vaults/my-campaign sleep

The full guide, docs/USAGE.md, covers connecting agents, scheduling, the daily review, disputes, upgrades, and vault CI.

MCP tools

For local agents, hippo serve --agent <id> (stdio) or hippo serve --http <port> provides:

Tool

Purpose

onboard

Who you are (lane, authority, quests), plus the handbook

remember

Queue an episode (fast, never blocks on the LLM)

recall

Search entities, with graph neighbors and pending episodes

get / neighbors

Full entity note / graph walk

ask_canon

The canonical answer to a factual question, with status and disputes

briefing

"Previously on…": chronicle, changes, upcoming deadlines, disputes

update_quest

Objectives, status, clocks, deadline, owner

How facts stay honest

  • Every fact has a status: canon / rumor / disputed / retconned.

  • An agent is authoritative for entities tagged with its authority domains (party/<id>.md). There its word is canon immediately. Elsewhere it's a rumor until another agent corroborates it.

  • Precedence is human > lane authority > corroboration > recency. A source may correct its own earlier report.

  • Contradictions between peers, or against the human, open disputes/<…>.md. Set ruling: there and the next sleep makes it canon.

  • Secret fields are age-encrypted to secrets/<entity>/<field>.age. The note only holds secret://…, and the curator can encrypt but never decrypt.

Contributing

pnpm install
pnpm test
pnpm typecheck

Path

What

packages/core

Schemas, markdown and managed regions, vault model, reconcile rules, search, handbook, service, secrets, migrations

packages/curator

LLM adapter (AI SDK) and the sleep pipeline

packages/mcp

MCP tools and resources

apps/cli

The hippo CLI, published as @mehrad77/hippocampus

vault-template/

What hippo init copies

seeds/example-relocation/

Fictional example campaign

Read CONTRIBUTING.md and docs/DEVELOPING.md (developing against your own private vault without leaking it). Coding agents: see AGENTS.md. Architecture: DESIGN.md.

License

AGPL-3.0

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