Models

GET /v1/models lists what this gateway offers, whether each engine answers right now, and what is pinned.

NameCheckpointWindowState read (short question / 10-20 options)Notes
jerschosen by its language routerreads the script and language of the state, then picks English or multilingual; typed-decisions only when named
jers-latestalias of jerspin a checkpoint name before relying on exact behaviour
jers-englishModernBERT-large, 421M parameters512 tokensabout 475 / 330 tokensthe most measured here; the engine's authors report 0.78 on MASSIVE intent in English (0.86 on English XNLI)
jers-multilingualmmBERT-base, 322M, 100+ languages1024 tokensabout 990 / 780 tokensthe engine's authors: +21 points over English on non-English XNLI; Swedish 0.57 against English 0.78
jers-typed-decisionsModernBERT-large fine-tuned on four workflows1024 tokensabout 990 / 790 tokens0.77 on its own workflows (customer service, invoices, security incidents, agent traces), where the base checkpoints score 0.34 to 0.36 against a 0.46 majority baseline; best for multi-question workflow decisions like those
jers-ft-<tenant>-<date>fine-tuned on one tenant's golden cases (jers_finetune.py)as its baseas its baselisted by GET /v1/models only for that tenant, with "fine_tuned": true and its held-out accuracy; registered only when it beat its base on held-out cases

Window figures measured on 2026-09-23 with this gateway's engine (see State); accuracy figures are the engine's authors' unless marked. The English checkpoint answers a three-question request in 22 to 25 ms of engine time on this Mac (medians of 20 requests, three runs, 2026-09-23).

default, auto and jers-latest are aliases of jers. An unknown name is a 422 that lists these. Every answer carries model (the model name with aliases resolved: jers-latest, default and auto come back as jers) and engine (the engine's name, the checkpoint that answered, and its metadata), so you always know what produced a number. The engine's authors report that the English checkpoint collapses outside English while staying confident, which is why jers routes by language before the engine reads anything: name jers-english only for English states.

Versions

GET /v1/models reports the runtime library version and the loaded checkpoints; treat jers-* names as "the checkpoint Jers runs today", record engine from the answer next to any measurement, and run your golden set (Quality) before and after the engine is upgraded.