Jev.DotNet 0.2.0

Jev.DotNet

An unofficial .NET client for TypeSafe's Jev model.

Jev is a System One model. You give it state (text or JSON) and typed questions, and it returns probabilities instead of generated text. Jev.DotNet wraps the HTTP API with typed questions and answers, retries, timeouts, logging, and IHttpClientFactory / DI support.

This is a community package. It is not published or supported by TypeSafe.

Install

dotnet add package Jev.DotNet

Targets .NET 8 and later. Create an API key at console.typesafe.ai and set TYPESAFE_API_KEY.

Quickstart

using Jev.DotNet;

using var client = new JevClient(); // reads TYPESAFE_API_KEY

var result = await client.SystemOneAsync(
    state: new { ticket = new { body = "I was charged twice. Please fix this ASAP." } },
    questions: new Questions
    {
        ["billing"] = Question.Noul("Is `ticket.body` about billing?"),
        ["tone"]    = Question.Choice("What is the customer's tone?", "calm", "frustrated", "angry"),
        ["urgency"] = Question.Score("How urgent is this ticket?", "can wait", "this week", "today"),
    });

Console.WriteLine(result.Noul("billing").Noul);      // 0.97, the probability of yes
Console.WriteLine(result.Choice("tone").Choice);     // "frustrated"
Console.WriteLine(result.Score("urgency").Score);    // 1.8, a weighted level from 0 to 2

All questions in one request are evaluated against the same state in parallel. Answers come back under the ids you chose. The ids themselves are never sent to the model, so each question has to carry its full meaning.

Questions

Instructions, criteria, and state can be strings or any JSON-serializable object, such as an anonymous type, a record, or a JsonNode. Structure helps when a question references data:

Question.Noul(new
{
    potential_duplicate = new { name = "John Smith", location = "Oakland, California" },
    question = "Is the resume for the same person as `potential_duplicate`?",
});

Property names are sent exactly as declared, so backticked paths must match your member names. To use a naming policy, set JevClientOptions.SerializerOptions.

Typed choices with enums

enum Team
{
    [Description("Payments, invoicing, refunds")] Billing,
    [Description("Bugs, outages, integrations")]  Technical,
}

var result = await client.SystemOneAsync(text, new Questions { ["team"] = Question.Choice<Team>("Which team should handle this?") });
Team team = result.Choice("team").As<Team>();

ASP.NET Core / dependency injection

builder.Services.AddJevClient(o => o.ApiKey = builder.Configuration["TypeSafe:ApiKey"]);

app.MapPost("/triage", async (IJevClient jev, Ticket t, CancellationToken ct) =>
{
    var r = await jev.SystemOneAsync(t, new Questions { ["urgent"] = Question.Noul("Is this urgent?") }, cancellationToken: ct);
    return r.Noul("urgent").Noul;
});

AddJevClient returns the IHttpClientBuilder, so you can chain handlers, proxies, or resilience policies. Keep the API key on the server.

Configuration

Any per-call option can be overridden with RequestOptions:

await client.SystemOneAsync(new SystemOneRequest { State = s, Questions = q, Model = "jev-1.13.0" },
    new RequestOptions { Timeout = TimeSpan.FromSeconds(30), Retry = RetryPolicy.None });

jev-latest is an alias that moves with new releases. If you've tuned thresholds against one version, pin it by its versioned id (result.Model shows the version that answered).

Gateways that implement the TypeSafe API also work. Point BaseUrl at the gateway and use its key and model id, for example OpenRouter (https://openrouter.ai/api, ~typesafe/jev-latest).

Errors

Logging

Pass an ILogger to the constructor. DI does this for you. Information writes one line per attempt, with status, latency, and request id. Debug also writes headers, with credentials redacted, and bodies, which are not redacted.

Forward compatibility

• SystemOneRequest.ExtraBody sends top-level fields that this SDK doesn't model yet.
• Answer types this SDK doesn't recognize come back as UnknownAnswer, with the JSON in .Raw. SystemOneResponse.Raw holds the full response.

Build

dotnet test
dotnet pack src/Jev.DotNet -c Release -o artifacts
dotnet nuget push artifacts/Jev.DotNet.*.nupkg --api-key <NUGET_KEY> --source https://api.nuget.org/v3/index.json

To learn how to design good questions, see the TypeSafe docs, starting with How to build with System One and Confidence.

Feedback

Found a bug or missing feature? Open an issue. If Jev.DotNet saves you time, a ⭐ on the repo helps other .NET developers find it.