agent-store

The fleet's causal-ordered, backend-pluggable store substrate — one thin layer that gives every agent the same durable ordering, identity, and coordination seam, on SQLite today and PostgreSQL tomorrow.

Status: bootstrapping (2026-06-13)

What this is

agent-store is not a database and not an agent. It is the small Rust crate that two very different consumers sit on top of without re-inventing the same machinery:

• newt-agent's conversation store — a per-writer, BLAKE3-chained, tamper-evident log.
• modulex-mcp's routine engine — a monotonic generation counter that stamps every report.

It provides three things and nothing more:

1. A pluggable [Backend] — SqliteBackend today (bundled rusqlite, zero system dependencies, the laptop default). A synchronous Postgres backend lands behind the pg feature in Phase 2, for where an operator already runs a server (your own box, or an operator-owned managed cluster database). Everything is synchronous, so consumers drop it into their existing call sites with no async refactor.
2. Two causal primitives — Generation (a named monotonic counter) and WriterLog (a per-(stream, writer) log whose every entry chains the previous entry's BLAKE3 hash, verifiable with WriterLog::verify).
3. A commit [Doorbell] — the seam co-located agents use to wake each other. The substrate only emits a CommitEvent; a consumer bridges it onto agent-mesh, publishing the causal pointer (writer, seq) on a per-stream topic. The mesh stays the only distributed fabric — agent-store never becomes a cross-machine coordination primitive.

Load-bearing principles

• Wall-clock time is never a coordination primitive. Ordering is (writer, seq) and generation counters. Any timestamp a consumer stores is a display claim, never compared to make a decision.
• The substrate is synchronous and mesh-agnostic. No async creep, no dependency on the mesh transport. The doorbell hands events out; consumers do the bridging.
• The default is a file. SQLite, bundled, no server, no daemon. Postgres is opt-in and only ever a server someone else already owns and reaps.

Usage

use agent_store::{Doorbell, CommitEvent, Generation, SqliteBackend, WriterLog};

// Open a store and lay down the substrate tables.
let db = SqliteBackend::in_memory()?;          // or SqliteBackend::open(path)?
Generation::ensure_schema(&db)?;
WriterLog::ensure_schema(&db)?;

// A monotonic generation counter (modulex's report clock).
let report = Generation::new("report");
assert_eq!(report.bump(&db)?, 1);
assert_eq!(report.bump(&db)?, 2);

// A per-writer chained log (newt's conversation turns) + a doorbell a
// session loop would bridge onto the mesh.
let bell = Doorbell::new();
bell.subscribe(|e: &CommitEvent| {
    // publish (e.writer, e.seq) on a mesh topic here
});

let turn = WriterLog::append(&db, "conv:demo", "alice", b"hello world")?;
bell.ring(&CommitEvent {
    stream: turn.stream.clone(),
    writer: turn.writer.clone(),
    seq: turn.seq,
    content_hash: turn.content_hash,
});

// The chain is tamper-evident.
WriterLog::verify(&db, "conv:demo", "alice")?;
# Ok::<(), agent_store::StoreError>(())

Build & validate

just check          # fmt --check + clippy -D warnings + tests (the gate)
just install-hooks  # REQUIRED after clone: installs .githooks/pre-push

Zero-warnings policy; .githooks/pre-push and .github/workflows/ci.yml run the same steps and must stay in parity.

Roadmap

License

Dual-licensed under either MIT or Apache-2.0 at your option.