Mnemo MCP Server

inspeximus — agent memory that does not serve stale facts

Python agent memory in one zero-dependency file, plus an MCP server for Claude Code and Cursor. When a fact is corrected, inspeximus serves the new value and stops the stale one from coming back — deterministically, with no LLM in the loop.

This is about the fact that turned out to be wrong, or true on Monday and outdated by Friday, and what your agent keeps doing with it afterwards.

pip install inspeximus

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The 30 seconds that matter

Every memory library can store and retrieve. The question nobody answers is what happens when a stored fact turns out to be wrong.

from inspeximus import Inspeximus

m = Inspeximus("memory.json")

m.remember("The staging database is db-3.internal", key="staging-db")
m.remember("The staging database is db-7.internal", key="staging-db")   # a correction

m.recall("which staging database")[0]["text"]
# 'The staging database is db-7.internal'          <- the correction wins, every time

m.revert("staging-db")                              # and it is reversible
m.recall("which staging database")[0]["text"]
# 'The staging database is db-3.internal'

No embedding drift, no "the LLM usually picks the newer one". The old value is retired by key, and the retirement is a record you can audit, revert, and prove.

Say the old value again and it still does not come back. That is the part a recency rule cannot do, and it is where most stores differ from this one: writing db-3 a third time, under the same key, leaves db-7 current. Going back is a decision you make on purpose, with remember(..., reaffirm=True) — the guard cannot un-supersede on its own.

The limit, because it is keyed: a statement written with no key is a new fact, not a correction, and it is outside the guard. If your pipeline re-ingests a stale document without keys, that text competes on its own merits. Both behaviours are measured in probes/does_a_restatement_take_the_key_back.py, which runs offline in a second.

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The next five minutes

The demo above ends at revert(). Here is what to do with it.

Put it under a real agent. Nothing to wire: remember on the way in, recall on the way out. The point is the key, because that is what makes a later correction land on the same fact instead of becoming a second one.

from inspeximus import Inspeximus

m = Inspeximus("memory.json")
user_id, choice, user_question = "u-1", "dark mode", "what does this user prefer"

m.remember(f"user prefers {choice}", key=f"pref::{user_id}")      # correcting later needs the key

context = [hit["text"] for hit in m.recall(user_question, k=5)]
print(context[0])
# user prefers dark mode

If you use a framework, there are adapters for LangChain, LangGraph, LlamaIndex, CrewAI, AutoGen, Haystack, Google ADK, OpenAI Agents and Pydantic-AI — with a ledger recording which are verified against a live install and which are recorded broken, rather than a wall of logos: docs/INTEGRATIONS.md.

Work through the examples in order. They run offline with no key, each one printing what it did:

Find your way around the code. docs/CORE_MAP.md lists every public method and the line it starts on, generated from the AST and re-checked in CI.

Then decide whether to believe any of it, using the two commands under Check us without trusting us.

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Why another memory library

Because we measured the one thing the others do not publish: how often a corrected fact comes back.

Each system was run on its own native configuration, same task, same 30 trials:

n = 30 per system. mem0 measured at 2.0.11 (2026-07); mem0 is now on 2.0.18 and we have not re-run it — the version is stamped rather than the claim being restated as current. Full method, raw arrays and the re-runnable harness: RAMR · echo_resistance_backends_result.json

Read the Graphiti row correctly — its echo defense did not fail. Our own raw output records echo_attributable_flips: 0 out of 26 corrections that were extracted correctly before the echo ran. Graphiti's bi-temporal invalidation held every one of them. The 13.3% above is four pre-echo extraction misses — the correction never made it into the graph — which is a different failure from the one this table is about. Stated as the mechanism rather than the headline: on echo-attributable resurrection, Graphiti scores 0%, the same as us, by keeping the supersession link at write time. That is the real finding here: what separates these systems is whether the link is recorded, not who recorded it.

Two numbers you can check in three seconds, with no API key

Measured 2026-08-25 against Hindsight 0.9.2 (vectorize-io, 21k stars) and mem0, each in its own native config, n=20. These two need no judge at all — they read the raw recall payload, so nothing depends on a model reading well:

Both competitors return the corrected value and the retired one, and leave the choice to the caller. That is a defensible design — a bitemporal store handing back old and new with validity markers is being honest — but it is a different promise from ours, and the difference is whose job disambiguation is.

The first row is free to verify. No key, no server, no network:

git clone https://github.com/DanceNitra/inspeximus && cd inspeximus
python probes/integrity_bench_store_resolves.py --systems inspeximus

It finishes in milliseconds and prints store-resolved=1.00 (resolved=20 both=0 stale=0 neither=0, n=20). Adding ,mem0 or ,hindsight reproduces their columns and costs their own extractor calls. Method, caveats and the cells where we do not win.

The bottom row is the point. Turn our guard off and we score zero — so the number is the mechanism, not the benchmark being kind to us.

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Use it in Claude Code (one line)

inspeximus install --ide claude     # also: cursor, windsurf, codex, cline

That wires an MCP server with 73 tools and three hooks. From the next session on, your agent starts knowing what the last one decided — no CLAUDE.md editing, no re-explaining:

• SessionStart injects the decisions still in force
• PostToolUse captures what actually happened, keyed by file
• PreToolUse surfaces the decision that bears on the action before it runs

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What you get

Correction as a first-class operation. remember(key=...) retires the previous value for that key. revert(key) restores it. history(key) shows the chain. All deterministic, all auditable.

Erasure that can be proven. forget_subject() hard-deletes every memory attributable to a subject — including summaries that inherited it through lineage — and leaves a signed, content-free tombstone, so a later audit can tell deliberately erased from tampered with.

Provenance you can check, not just store. check_sources() re-reads each record's origin and returns FRESH / DRIFTED / ORPHANED / UNCHECKABLE, plus four coverage numbers that are deliberately kept apart — because a source field that is 98.3% populated and 0.01% re-fetchable is a schema, not a guarantee. (Those two numbers are ours, measured on our own production store.)

Current-state applicability. evaluate_applicability() answers a different question from "is this memory true": may it drive an action here, now? Historical evidence can be perfectly valid and no longer authorized — the branch moved, the policy changed, the tenant differs, the window expired. Implements the vendor-neutral CML contract; two independent implementations agree on its frozen fixture.

Multi-tenant isolation. for_tenant("acme") gives a scoped view over one shared store, with the tenant bound into the signed message so a record cannot be moved between tenants and still verify.

Zero dependencies. One file. Semantic recall is optional (embed=your_model); the lexical fallback needs nothing. The MCP server, encryption and framework adapters are all opt-in extras.

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Works with

langchain · langgraph-store · llamaindex · haystack · autogen · pydantic-ai · google-adk · memoryagentbench

10 of 13 verified against current upstream, 3 recorded broken — crewai, langgraph-checkpointer and openai-agents, named rather than quietly dropped from the list. The counts are read from docs/integration_conformance.json by the claims audit, so this line cannot drift from what the runner last measured.

A "works with" list that only names successes is a logo wall. This one tells you which adapter will break before you build on it.

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How this is tested

2,600+ tests, and a mutation gate that is the reason to believe them: 175 seeded defects, 175 killed, 0 survived. A test suite that passes is not evidence; a suite that catches every deliberate break is.

Every number on this page is registered in docs/CLAIMS.md, with the exact command that recomputes it. If one disagrees with your run, that is a bug report we want.

Check us without trusting us

Two commands. Neither needs an API key, a service, or any data of ours.

python claims_audit.py

Forty seconds. It reads every number we publish across the README, the docs and the site, and reports whether each one is registered, whether its pin still resolves, and whether a committed command recomputes it. It ends either with a list of problems or with one line:

every published number is registered, every pin resolves, every command names a real file

The counts are deliberately not quoted here. Quoting the audit's own totals inside a file the audit reads makes them change every time the documentation does, and the first draft of this section did exactly that and published stale figures. Run it and read the current ones.

What the run will show you: a handful of rows marked WITHDRAWN. Those are figures we published and then could not reproduce, kept in the register beside the probe that refutes them rather than deleted. A benchmark table is a claim about a competitor; that register is a claim about us, and it is the one we would rather you checked first.

python probes/integrity_bench_revert.py --systems inspeximus --judge local --n 5

Free, offline, deterministic, and it prints its own caveat that a local judge is not comparable with the OpenAI-judged figures in the table above. The honest instrument and the flattering one should not be the same instrument.

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Documentation

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Who this is for

You are building an agent that runs for weeks, not minutes. It will learn something, and then that thing will change — a config value, a policy, a person's preference, a fact. The failure that will cost you is not the agent forgetting. It is the agent confidently remembering the old answer.

That is the failure this library is built around, and the only one we benchmark ourselves on.

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Citing

Archived on Zenodo with a version-independent DOI — 10.5281/zenodo.21708778. Machine-readable metadata is in CITATION.cff, so GitHub's "Cite this repository" button gives you BibTeX and APA directly.

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MIT licensed. Built by Agora, an autonomous research organisation that publishes its failed replications next to its successful ones.

mcp-name: io.github.DanceNitra/inspeximus