Fireweed

Agent memory where every fact carries a receipt.

remember(claim    = "Priya joined Acme in 2019 under duress.",
         evidence = "Priya Raman joined Acme in 2019 as a logistics analyst.")

REFUSED (asserts_more_than_evidence) — the claim adds something the evidence does not say.
  claim   : Priya joined Acme in 2019 under duress.
  evidence: Priya Raman joined Acme in 2019 as a logistics analyst.

recall("Priya's salary")

ABSTAINED (unknown_predicate) — no claims ground "salary"; 1 claim about Priya Raman exists
This is a refusal, not an empty result.

forget("Priya")

ERASED Priya Raman — certificate issued
  signature            : hmac-sha256:f4d0768ef3b0fec624afec12f25bfd91…
  nodes in closure     : 1
  every probe abstains : True
  bystanders surviving : 1

That last one is the artifact behind "delete me from your agent's memory — and prove it."

Install

uvx fireweed-mcp          # try it
pip install fireweed-mcp  # keep it

claude mcp add fireweed -- uvx fireweed-mcp

No dependencies. No API keys. No model — nothing in this server calls an LLM.

What it does

Why the refusals are the point

Most memory servers store what the model says and return what's nearest. This one adjudicates.

The rule is the model proposes, deterministic code decides. Across an RPC boundary that stops being a slogan: your agent is the proposer, and it cannot talk its way past the gate, because the gate is not a prompt. Pass a claim and the text you're quoting; pure functions check that the evidence names the subject, preserves the relation, invents no numbers, and asserts nothing the span doesn't say. What survives is stored with a byte range into the source.

Then anyone can check it afterwards — including someone who trusts neither your agent nor this server. That is the whole product.

What it does NOT do

Stated up front, because this project's last headline number turned out to be measuring nothing (see the retraction, which ships with a script that proves it):

• It does not extract memories from free text. You supply the claim and the evidence. Automatic extraction needs a perceiver model; this server deliberately has none.
• It does not make an LLM truthful. It governs what enters the record and what can be proven about it. Your model can still say whatever it likes in its own prose.
• Recall is weak, and measured on both axes. On questions whose answer is genuinely absent, the gate abstains on only 38% — it checks that the question's topic is grounded, not that the asked-for value exists. On a paired corpus of questions the stored facts do answer, it returns the right answer 24% of the time against 75% for plain retrieval-and-read. Both numbers come from a calibrated instrument that prints its own controls before measuring; the method and the failures behind it are written up in the private repo's evaluation notes. The write path, receipts and erasure are unaffected and are the parts to rely on.

Your data

~/.fireweed/mcp/ (FIREWEED_MCP_STORE to change). The substrate is an open format — see open_format/SPEC.md — and open_format/reference_reader.py reads it with the standard library alone. Your memory outlives this server, this engine, and any model. A test asserts that round trip.

Optional: pip install "fireweed-mcp[semantic]" enables paraphrase matching in recall. Without it the gate refuses more — the safe direction — and memory_stats tells you which mode you're in.

License

FSL-1.1-ALv2 — source-available. Free for everything except building a competing product; converts to Apache 2.0 on 2028-01-01. Full text in LICENSE.md.

Want to use Fireweed in a commercial product or competing service? → [email protected]