SemIf (formerly OpenJev)
Semantic ifs from open models, in your browser.

A live, local experiment

Decision model in your browser.

A local model can either read probabilities for your allowed options without decoding them, or write the same kind of distribution token by token. Pick a size, run both on your own GPU, and measure the difference.

browser onlyno backendyour timings1.56 GB model

There is no waitlist! Just try it out ↓

MiniCPM5 2B is selected by default. On a phone or smaller device, switch to Qwen3 0.6B in the model box if needed.

00 / setup

Load the model once

Larger model. Loading may be slower or may not fit on some low-end devices.

Measured model qualitynative checkpoints · owned + public benchmarks
ModelDownloadAuthoredPerturbedTypeSafe
Qwen3 0.6B639 MB44.0%52.8%40.7%
MiniCPM5 2B1.56 GB68.6%69.3%63.7%
Qwen3.5 4B3.01 GB81.3%76.6%84.5%
Published Jevhosted88.3%

Owned columns are balanced accuracy. TypeSafe is equal-case agreement on the same 102-row public subset; Jev is the published value. Browser quantization may change model accuracy.

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download / cache
starts only when you click load
model loaddownload and prepare
warmupcompile passes for both methods

Weights come from Hugging Face and remain in your browser cache. Inputs never leave this page. First load can take several minutes depending on the selected model, network and GPU.

01 / decision

Give it a real choice

Try an example
Allowed options
3 / 20

Both paths receive the same decision. One reads option probabilities directly; the other asks the model to write its option probabilities as JSON text.

your decisionstate + question + options
same local modelMiniCPM5 · 2B
read logitsA…T probabilities
write tokens{options + probabilities}

02A / direct readout

Choice probabilities

no decoding

Read the model’s choice logits and normalize only across the options you supplied.

waiting for a run
total
input
output
1 readout

02B / generation

JSON probabilities

token by token

Ask the model to estimate the same displayed-option distribution and write it as JSON. Watch every token arrive.

waiting for a run
first token
total
input
output
measured wall-time ratiorun it on your GPU

The methods run sequentially on the same loaded model so they do not contend for one GPU. Direct runs first, then generation.

What these numbers do—and do not—mean

Conditional probabilities. Direct scores are a softmax over only the displayed option tokens. They are not calibrated confidence and do not include every answer the model might prefer.

Local model tiers. The phone model trades accuracy for size. MiniCPM is the desktop default. The 4B option needs substantially more memory. None is claimed to match Jev.

Real local timing. Setup, warmup, prompt preparation, direct execution, first generated token and generation completion are timed with performance.now(). No canned results appear.

Quantized weights. The demo uses pinned GGUF builds through wllama. Quantization can change both quality and speed.