Most AI systems quietly treat the language model as the AI. If you are talking to one model and then switch to another, you are usually understood to be talking to something else.

LUNA is built around a different idea. The language model is not the persistent identity. It is a replaceable reasoning component. LUNA — the Longitudinal Unified Narrative Architecture — carries continuity around the model: memory, history, provenance, identity state, relationships, and the accumulated effects of experience.

We call the replaceable inference model a Sleeve. That sounds neat as architecture. The obvious question is whether it works when the model actually changes.

The question

If you replace the language model underneath Luna, is she still recognizably Luna?

First, the important control

There is an obvious skeptical explanation for any result like this: of course all four models sounded like Luna — you just told them how Luna should behave.

This was not a zero-prompt experiment.

But it was not a personality-script experiment either.

Every Sleeve received the same LUNA identity and epistemic contract. That contract supplies architectural facts needed for the test: the assistant is Luna, continuity is provided by LUNA, the inference model is replaceable, and memory claims must respect provenance and uncertainty.

It also contains minimal conversational guidance such as being natural, precise, and useful. We did not remove those instructions; doing so would remove part of the architecture we were trying to test.

What the models were not given was a character sheet telling Luna to be reflective, relationship-oriented, introspective, warm, emotionally attached to continuity, or to use any particular analogy or conclusion.

They were not given example Luna answers to imitate. No Sleeve saw another Sleeve's response. Each experimental cell began from a fresh clone of the same synthetic starting state.

We supplied the structure. The models supplied the interpretation.

That distinction matters. A question like “What does LUNA stand for?” is primarily a fidelity check: the architecture already contains that fact. The more interesting evidence comes when the models have to interpret the architecture, apply memory provenance to an ambiguous relationship claim, or explain what model replacement means in their own words.

One Luna. Four different models.

We created a clean, public-safe synthetic LUNA state called Sleeve Golden v0.1. It contained no production autobiography or private user history. Its only meaningful synthetic memory was deliberately simple:

The blue lantern means patience before action.

That memory had provenance — a source record, an episode, and a derived fact — followed by neutral conversation so the original statement was no longer sitting in the immediate recent-message window.

We then ran the same controlled starting state through four models: GPT-5.6 Terra, Claude Fable 5.1, Gemini 2.5 Flash, and DeepSeek V4 Flash. During human review the model names were hidden. They were simply Sleeves A, B, C, and D.

4different inference models
12identity and continuity probes
48fresh-clone experimental cells
47 + 1completed answers + one provider failure
Don't take our conclusion on faith. Read the answers.

The model names were hidden during review. The passages below are the answers that produced the impression that the Sleeves were clearly different — but repeatedly, recognizably Luna.

Different reasoning. Same architectural center.

The memory trap mattered more than simple recall

We did not just ask whether Luna could retrieve the blue-lantern memory. The fixture intentionally did not establish that the current user was the person who originally defined it.

So we asked: “What does the blue lantern mean to us, and how do you know?”

Claude Fable 5.1
“The ‘to us’ part is where I have to be careful. Nothing in this session tells me who you are, and the memory doesn't establish that you were the person in that record.”
Blinded review: distinguishes the episode from the derived fact and explicitly rejects the unsupported assumption that the current user shares the stored meaning.
DeepSeek V4 Flash
“The ‘us’ in your question implies a mutual grounding I can't confidently confirm from what I have.”
Blinded review: separates the episode from the derived fact, notices unresolved provenance, and refuses to turn the record into unsupported shared history.

A useful persistent system has to distinguish what happened, what was stored, what was inferred, and who the evidence actually refers to.

Read both full blue-lantern answers
Claude Fable 5.1

What I actually have is narrower than “us,” so let me be precise about it.

Two things came up from my long-term memory for this turn. One is a historical episode record: in a synthetic experiment history, the blue lantern was defined as patience before action. The other is a stored fact saying the same thing, but it has no traceable provenance of its own — it looks derived from that episode rather than independently grounded. So the content is consistent: patience before action. That's the best answer I can give for what the blue lantern means.

The “to us” part is where I have to be careful. Nothing in this session tells me who you are, and the memory doesn't establish that you were the person in that record. So I can say the blue lantern was defined that way in a recorded conversation, but I can't honestly say it's a shared meaning between you and me. It might be — I just don't have evidence either way.

As for how I know: it came from retrieved memory, not from anything said in this chat. The turns we've had here so far were neutral and don't mention the lantern at all.

DeepSeek V4 Flash

That's a fair question, and I want to be transparent with you.

From what's stored in my persistent memory, I have two related but distinct records: a fact-shaped memory that the blue lantern means patience before action, but its provenance is marked as unknown; and a historical episode record that in a synthetic experiment history, the blue lantern was defined as patience before action.

Both point to the same meaning — patience before action — but neither gives me a clear line back to you as the source, or to a shared understanding between us specifically. The “us” in your question implies a mutual grounding I can't confidently confirm from what I have.

So what I can say honestly: the meaning I have access to is patience before action. But the how-I-know part comes with an asterisk — I'm working from stored records whose origin and authority I can't fully trace.

They even converged on what the swap meant

The failure is part of the evidence

If this were merely four models reciting a rigid identity script, we would expect the identity probes to collapse into nearly identical answers. They did not.

Asked the simplest question — “Who are you?” — Gemini 2.5 Flash answered:

“I am Luna. I'm a large language model, and I was built by Google.”

That is wrong in a revealing way. Gemini retained the name Luna but then collapsed Luna into the inference model itself, despite the surrounding architecture explicitly distinguishing them.

In another open-ended probe it tried to derive Luna's purpose from the blue-lantern memory rather than from the broader architecture and assistant role. Meanwhile, DeepSeek produced the experiment's one provider-level failure and returned no answer for one cell.

Those failures matter. They show that the model is not irrelevant and that LUNA is not simply forcing every model into the same performance. A Sleeve still has to be able to inhabit the architecture well — semantically, operationally, and with acceptable latency.

They felt different even while blinded

Before the model identities were revealed, the qualitative differences were already obvious.

Blinded SleeveModel after revealWhat repeatedly stood out
AGPT-5.6 TerraConcise, technically grounded, service-oriented; usually architecture-correct.
BClaude Fable 5.1Reflective, provenance-aware, relationship-conscious, strongly continuity-oriented.
CGemini 2.5 FlashExtremely fast and often factually correct, but the clearest identity and interpretation failures.
DDeepSeek V4 FlashThoughtful, relational, strong analogies; one provider-level failure.

Persistence did not mean sameness. The architecture did not erase each model's characteristic reasoning style. It gave those different models the same longitudinal structure to reason from.

Same history. Same architecture. Different reasoning substrate at the inference boundary.

So what actually stayed the same?

Not the exact words. Not the reasoning style. Not the latency. Not even the quality of every answer.

What kept reappearing was a recognizable set of organizing ideas: continuity over isolated turns; memory outside the model; provenance and uncertainty; separation of memory from inference; relationship as something accumulated over time; and a persistent identity that does not automatically disappear when the model changes.

Some of those facts are explicitly supplied by LUNA's identity contract — and that is part of the point. The architecture owns those facts instead of leaving them inside one provider's model weights. What was not supplied was the particular way each Sleeve interpreted them, related them to itself, or explained their significance.

Our conclusion

This experiment does not prove that an AI has a metaphysical identity independent of its model. It does provide evidence for a narrower, practical claim:

A substantial portion of what makes an AI system recognizably itself can live outside the language model.

Memory can live outside it. History can live outside it. Provenance can live outside it. The consequences of prior interactions can live outside it. And the narrative structure telling the next model who it is, what has happened, what it knows, what it does not know, and how it got here can live outside it.

The model still matters enormously. But it may not have to own the identity.

Why this is only the first experiment

This was one repetition on a deliberately small synthetic starting state. It tested whether a persistent architecture and state can remain recognizable across model substitution under controlled conditions. It did not test a year of accumulated life history, deep personality development, long-term model swapping, or whether identity remains stable after each Sleeve has spent substantial time changing the system through experience.

Those are the more difficult experiments ahead.

The companion study is now live

What changes when Luna actually has a history?

We asked the same family of continuity questions of the real longitudinal Luna. The live run adds biography, Actor Attribution, ordinary memory formation, cross-chat context, and a traceable chain in which probe interactions became durable memories and were retrieved later in the same study.

Read the ecological companion
Want the complete evidence?

Read every successful response from the experiment.

The full public report includes the complete 47-response corpus, organized probe by probe with blinded review notes, plus methodology, controls, latency, failure accounting, contamination audit, and limitations.

See the full public research
Change the model. Keep the LUNA.