leonardsellem/hypermnesic

One brain. Every AI. Yours.
Your second brain lives as plain Markdown in a Git repo **you** host. ChatGPT, Claude, and
your coding agents — on your laptop *and* your phone — all read and write that **same** brain
through one endpoint. Obsidian is how you browse it.
Here's the part that matters: because every AI keeps **curating** the same notes, your memory
doesn't just persist — it **compounds**. Every fact captured, every correction, every link
added makes the next answer from *every* assistant sharper. Per-app memory traps you in silos;
one shared brain gets smarter each day — and it's plain files you own, not rows in a vendor's
database.
**Every memory is a real Git commit** — reviewable, revertible, yours. The search index is a
disposable projection of your files; delete it and rebuild it any time. A reindex can never
lose a memory.
**Who it's for:** developers and power note-takers who want durable agent memory they *own* —
plain files in their own Git history, reachable by every assistant, with no vendor lock-in.
> **Status:** public v0.1.0 release. The engine is licensed under **AGPL-3.0-only**;
> the companion plugin ships from the separate GPL-3.0
> hypermnesic-companion
> repository.
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Why it compounds
Per-app memory **fragments**: what you told ChatGPT is invisible to Claude, your phone's
assistant forgets what your laptop's agent learned, and none of it is yours to move. A shared
brain does the opposite — it turns every interaction into a flywheel:
- **Capture** — any AI writes a note: a decision, a fact, a person, a meeting.
- **Curate** — any AI links it, corrects it, or adds context the next time it's relevant.
- **Recall** — every other AI retrieves it on the next question.
- **Compound** — the brain grows denser and more useful with every turn, for all of them.
Because every write is a reviewable Git commit, one assistant's curation is safe, visible, and
revertible for all the others. The brain is shared **and** trustworthy.
---
One endpoint, every client
Point any MCP-capable app at your endpoint URL and it just works — OAuth is automatic (log in
through the browser once, then silent refresh):
- **ChatGPT, Claude** (desktop, mobile, web) — add a custom connector.
- **Claude Code / Codex** — the bundled plugin.
- **Your own agents** — any MCP client, same URL.
- **Obsidian** — a read-only companion over your tailnet, for browsing and serendipity.
On the machine that holds the vault, skip the network entirely and use the hypermnesic CLI.
Setup details are in the Quick start below.
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How it's different
Most "agent memory" keeps your memories in *their* store. hypermnesic keeps them as **plain
Markdown in your Git repo**; the search index is a throwaway projection you can delete and
rebuild at will. Everything else follows from that one choice.
| Question | Hypermnesic | Hosted memory layers |
| --- | --- | --- |
| Source of truth | Markdown files in your Git repo | Service-managed memory store |
| Writes | Git-first commits — reviewable, revertible | API/app-managed writes |
| Reach | One self-hosted OAuth endpoint every client shares | Per-product API or app feature |
| Compounding | Every AI curates one shared brain | Memory siloed per app |
How it sits next to tools you may know:
- **mem0 / Zep** — memory APIs over a managed vector (and graph) store. Reach for them if you
want a hosted memory *service*; reach for hypermnesic if you want **your files to be the
memory**.
- **Hindsight** — also open-source agent memory, but it lives in its own vector store you run
via Docker/cloud, and it posts a higher LongMemEval score on a more lenient judge axis.
hypermnesic optimizes for **owned, auditable, compounding files**, not a leaderboard rank —
read the honest comparability envelope in harness/BENCHMARKS.md.
- **Honcho** — *complementary*, not competing. Honcho models **who you are** (preferences,
style, theory-of-mind); hypermnesic holds **what you know**, in files. Use both.
- **A database-backed personal brain** — I built one before this. The database drifted from
the files, and I couldn't fully trust or move it. hypermnesic is the rebuild: files are
truth, the index is disposable.
Full tool-by-tool detail — including when hypermnesic is the *wrong* fit — is in