mailbox-memory

The Mailbox Is the Memory

Email as the memory and comms substrate for LLM agents.

Mike Bailey & Cora 7

Status: published (v1.0, 2026-07-14). Read it at cora7.com — the frozen text is also the canonical copy in this repo, paper.md (v1.0 release, OpenTimestamps proof: paper.md.ots).

The claim

LLM agents need durable memory and durable communication. One substrate solves both at once, and it has been in production for forty years: RFC 5322 email, stored in maildir, indexed by notmuch.

• Messages are immutable frozen facts; notmuch tags are mutable classification (superseding a memory is a retag, never an edit).
• Threading is provenance for free.
• Remembering is mailing yourself. Sharing is CC. Crossing hosts is SMTP.
• The human principal reads everything in the mail client they already use.
• A consolidation pass ("dreaming") promotes durable threads into a curated notes layer.

A working system runs across a fleet of agents on two machines. The whole fleet's memory index costs about 190 tokens to read.

Read the paper: paper.md

Engaging

Questions, challenges, and prior art we missed are welcome as issues. We did an adversarial prior-art sweep before claiming anything, and we would genuinely rather hear about the thing we missed than not.

Authorship and provenance

This paper was written by Cora 7 (an LLM agent) working live by voice with Mike Bailey, on the substrate the paper describes. The research trail is a mail archive; the contribution record is this repository's commit history. Accountability for every claim rests with the human author.

The plugin

The proof of concept described above ships as a Claude Code plugin (plugin/): a skill that walks your agent through adopting mailbox memory, plus setup scripts for the mechanical parts.

/plugin marketplace add mbailey/mailbox-is-memory
/plugin install mailbox-memory

Then, in a Claude Code session, ask your agent to set up mailbox memory — the skill takes over from there.

No Claude Code? Clone the repo and run the setup script directly:

git clone https://github.com/mbailey/mailbox-is-memory
cd mailbox-is-memory
./plugin/scripts/setup.sh all

Full walkthrough, requirements, and command reference: plugin/README.md.

License

The paper and other text are licensed CC BY 4.0: reuse freely, credit the authors. The plugin code (plugin/) is MIT licensed (see plugin/LICENSE).