JKToolKit.CodexSDK

A strongly-typed .NET SDK for the Codex CLI — launch it as a subprocess, stream events, and build integrations with a clean async API.

Three Integration Modes

Mode	Best for	Docs
codex exec	Stream JSONL session events from normal Codex runs	Exec docs
codex app-server	Deep, event-driven integrations (threads / turns / streaming deltas)	App Server docs
codex mcp-server	Using Codex as an MCP tool provider	MCP Server docs

Install

dotnet add package JKToolKit.CodexSDK

Prerequisites: .NET 10+ and Codex CLI on your PATH.

Quickstart

using JKToolKit.CodexSDK;
using JKToolKit.CodexSDK.Models;

await using var sdk = CodexSdk.Create();

// --- Exec mode: stream session events ---
await using var session = await sdk.Exec.StartSessionAsync(
    new CodexSessionOptions("<workdir>", "Write a hello world program")
    {
        Model = CodexModel.Gpt51Codex
    });

await foreach (var evt in session.GetEventsAsync())
{
    Console.WriteLine(evt);
}

// --- App Server: threads + turns + streaming deltas ---
await using var app = await sdk.AppServer.StartAsync();

// --- MCP Server: tool discovery + invocation ---
await using var mcp = await sdk.McpServer.StartAsync();

Documentation

Full docs, examples, and API reference live in docs/:

• Exec mode — sessions, streaming events, structured outputs, code reviews
• App Server — threads, turns, approvals, DI, resiliency
• MCP Server — tool discovery, sessions, follow-ups

Demo

dotnet run --project src/JKToolKit.CodexSDK.Demo -- "Your prompt here"

See more demo commands in the full docs.

License & Contributing

Contributions welcome — open issues or pull requests for bugs, features, or docs.