Laya
Convai Innovations' open-weights decision model. Apache 2.0, downloadable, runs on your own machine.
- The difference from the Jev page is not opinion, it is availability.Every claim below can be checked against a file you can download. Where the Jev page says not published, this page cites a line in a config.
What kind of model is it
An encoder.config.json
A BERT-family transformer that reads the whole input in both directions at once and produces no text at all. config.json says ModernBertForMaskedLM: hidden size 1024, 28 layers alternating full and sliding attention, mean pooling.config.json
That is the sharpest contrast with a chat model. GPT-style models are decoders: they predict the next token, then the next, building a sentence. An encoder does not predict the next anything. It reads, and it scores. One forward pass, about 33 ms, no tokens produced.model card
Full build: ModernBERT-large as the backbone, fully fine-tuned, plus a decision head trained from scratch (two transformer layers, an option-marker scorer, and an act/escalate head). 421M parameters in total.model card
How it reads the state
512 tokens per question on the English checkpoint, 1,024 on the multilingual one.model card
Separately, the decision head has its own budget for the options: head_max_len is 192 tokens on English, 256 on multilingual. That number matters, and question 6 explains why.model card
Every question in a call is answered in a single forward pass.model card
How it turns options into numbers
Every option you send gets its own [MASK] token.model card
The model scores each of those markers, then softmaxes across them, and that distribution is the answer. This is the part worth reading twice.model card
Which means the answer space is defined at request time, not at training time. The options live in your request, so new schemas need no retraining.model card
That is how a model trained on support tickets can answer LANE_LEFT versus IDLE on a highway: nobody taught it to drive, they taught it to read a situation and score the markers you supply.
How it was trained to be calibrated
RLCD, Reinforcement Learning for Calibrated Decisions, with the method published.model card
The policy reports a probability distribution. Exploration adds zero-mean Gaussian noise to the logits. The reward is a strictly proper scoring rule (log and spherical, plus ranked probability score for ordinal questions). Updates are REINFORCE with a group-mean baseline, the same idea as GRPO.model card
The phrase doing the work is strictly proper. Under such a rule, the only way to maximise expected reward is to report the probabilities you actually believe. Overclaiming is punished, so honesty is the optimal policy rather than a good intention.
TypeSafe uses the same name for Jev's training without publishing any of this.our inference, from the absence of a published method
What it costs to run
- Price
- Free. Apache 2.0. You pay for hardware, and nothing leaves your machine.model card
- Install
pip install laya. Weights, about 2.3 GB, download from Hugging Face on first use.- Speed, stated
- 39.5 ms for one question on a T4 GPU, 32.8 ms on the multilingual checkpointmodel card
- Speed, measured
- p50 107 to 185 ms across the three games, on a laptop CPU with no GPUmeasured here
| Checkpoint | Backbone | Params | Context | Aimed at |
|---|---|---|---|---|
| laya | ModernBERT-large | 421M | 512 | English, guardrails, email triage |
| laya-multilingual | mmBERT-base | 322M | 1,024 | 100+ languages, about 2.2x faster |
| laya-typed-decisions | ModernBERT-large | 421M | 1,024 | the four typed-decision workflows |
What it cannot do
- Handle many options well.The options share that fixed
head_max_lenbudget, so 77 options get roughly 3 tokens each and the labels blur together. On Banking77, Convai report Laya at 0.425 against Jev's 0.870.model card The limit is a consequence of the mechanism in question 3, not a mystery. - Match Jev on soft distributions.Higher argmax accuracy on typed decisions (0.766 against 0.727) but lower soft accuracy (0.471 against 0.580).model card
- Arrive calibrated out of the box.Its 0.081 ECE comes after domain temperature fitting. Raw, the base checkpoint is worse than Jev.model card
What we measured
Three games, zero training, 10 episodes each, on CPU.measured here
- Blackjack:chose stick on all 200 decisions, scoring exactly like an always-stick baseline. Matched basic strategy 49.5% of the time, which is what you get by not deciding.measured here
- Highway:64% of its moves were lane changes into a lane that did not exist. Average survival 18.1 seconds against Jev's 40.measured here
- Confidence runs backwards:when it claimed 80 to 90%, it was right about 55% of the time; when it claimed 90 to 100%, about a third.measured here
- The fairness note.This is a fair result for these games and an unfair one for the model. Laya was built for support tickets, moderation and routing, not for driving. On its own published benchmarks it beats Jev on accuracy (0.766 against 0.727 on typed decisions, 0.950 against 0.910 on AG News) and is three times better calibrated (ECE 0.081 against 0.246).model card, and Convai note that the Jev figures there are third-party published, not measured by them
- What these games measure is not which model is better. It is how far each one travels from the domain it was trained on, and games are much further from Laya's home than from Jev's.
- Its weights are open, so the obvious experiment is to fine-tune it on decisions like these and put it back in the arena. That is the next thing on the list.
Sources
Both models are days old and changing. Everything here was checked on 23 September 2026 against the sources listed above.