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Sonn — featured on BetaList
Memory & reasoning for AI coding agents

Stop re-explaining your codebase every session.

Start Free — no credit card ~2-min setup, one command
Catches repeats before code is written Learns your conventions

Sonn is a local-first reasoning layer for Claude Code — it remembers your decisions and stops your agent repeating fixed mistakes. Nothing to upload, no cloud account, no training on your code.

01 — The problem it solves

It catches the mistake
before your agent
makes it again.

A persistent process reasons over your history and steers before you ask — so settled decisions stay settled, instead of being relitigated every session.

Same prompt. Two outcomes.
session/cache.ts — claude code no memory
1$claude "add caching to the session store"
2
3reaches for an in-memory TTL cache
4→ stale sessions across pods
5ships — you catch it in review. again.
the bug you already fixed in May, written a second time.
session/cache.ts — claude code Sonn active
1$claude "add caching to the session store"
2
3recall: we settled this in MaySonn reasoned, before you asked
4use Redis with explicit invalidation
5the approach the team already agreed on
caught before a single line was written. settled stays settled.
02 — Why it's different

Not another
memory tool.

Persistent memory is table stakes — everyone has it. The whole category just stores text and hands it back. Sonn is the layer above that: it reasons.

Other memory tools
store embed search return

They compete on storage shape — vectors vs. graphs vs. paging. The memory itself never forms an opinion. They make the agent know more.

A filing cabinet.
Sonn
observe reason validate steer first

A persistent process reasons over the memory — forms opinions about what matters and injects guidance before you ask. It makes the agent behave better.

A mentor.
03 — How it works

A relay on your machine.
A brain on ours.

A lightweight relay sits next to Claude Code and streams every session to your private brain on Sonn. Three layers turn that history into guidance — fed back before you ask.

03
WhisperBehavior

Your rules become trigger-gated nudges that fire the moment they're relevant — changing how the model behaves, not just what it knows. The closest thing to fine-tuning a model without its weights.

02
AngelReasoning

A persistent process that reasons over the memory — forms opinions, extracts patterns, and surfaces the right context before you ask. When it isn't confident, it says so and re-queries instead of returning noise.

01
MemoryStorage

Records every session, embeds it, retrieves it with hybrid search. The part every other tool stops at.

04 — Your code stays yours

Nothing of yours
runs on our servers.

Sonn is local-first. Your memory database lives on your machine, and generation runs through your own model credentials — your source goes to the provider you already trust, never to a third-party server. We hold the reasoning logic. You hold the code.

your code→ your machine
memory db→ your machine
generation→ your own credentials
reasoning logic→ Sonn (our IP)
0bytes of your source on our servers
05 — The numbers that matter
0.0%
LongMemEval — on a local model
426 / 470 · competitive with the best published results
0
lines of your code on our servers
local-first · your own trust boundary
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Give your agent
a memory that thinks.

If you're reading this, you're early — and that means a lot to us. We're developers shipping the tool we always wanted. Try it, break it, tell us everything.

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built for claude code · local-first · early access