Codex Visual Studio 2026

Use Codex in
Visual Studio 2026
with your ChatGPT subscription.

Use the Codex access included in your eligible ChatGPT subscription inside Visual Studio 2026. Choose your model, tune its effort, and track your usage while working on your C# and .NET solution.

BRING YOUR OWN SUBSCRIPTION Sign in with your ChatGPT account.

Your Codex usage counts toward your plan’s allowance.

How subscription access works ↗
Get iolys Explore the integration
A closer look inside Visual Studio
The iolys Codex chat in Visual Studio beside the Codex Usage window, showing the usage percentage and available resets.
Real interface. Familiar workspace.Click to explore ↗
Model choiceReasoning effortFast modeUsage & resets

01 / Usage & resets

Know where you stand.
Keep your next reset in sight.

Open Show usage from the chat toolbar to see your Codex allowance without leaving your solution.

  • Your usage, at a glance.See the percentage used and the usage windows reported by your Codex account.
  • Know when your allowance refreshes.Check the reset time next to each available usage window.
  • Banked resets, right there.See your available usage resets, their expiration dates, and the option to use one when you need it.

Usage and reset availability come from your Codex account. The values in this capture are an example, not an allowance included with iolys.

FROM THE CHAT TOOLBARShow usage ↗
Codex Usage showing 54 percent weekly usage and three available full resets with expiration dates.
Usage and banked resets in one window.

02 / Models, effort & Fast mode

Set the pace.
Match the task.

A focused fix and a complex refactor need different settings. Keep the controls next to your prompt.

MODEL

Choose your Codex model.

Select from the models exposed by your Codex connection. Model choice stays part of the conversation, inside your IDE.

EFFORT

Give the hard problems more thought.

Choose a reasoning effort supported by the selected model. Adjust it to the depth of the task you are working on.

↯ FAST

Keep short iterations moving.

Enable Fast mode for a conversation when the selected model and account support it. The active setting stays visible in the model options.

ONE MENU. THREE CONTROLS.
iolys model options showing GPT-6 Astra, medium reasoning effort and Fast mode enabled.
The settings you need, where you need them.
TRY IT ON YOUR NEXT TASK

“Find the cause of this failing test.”

“Review this refactor across the solution.”

Choose the model and effort for the job. Use Fast mode when shorter response times matter.

Available models, effort levels, and Fast mode depend on your Codex connection and account. Fast mode can increase usage; provider conditions apply.

Read the Fast mode release notes

03 / Manage Providers

Move forward.
Keep a way back.

Download and manage the Codex CLI locally from Manage Providers. Installation, updates, and earlier versions are all in the same panel.

  • See exactly what is installed.Compare the installed and latest versions, with a clear indication of whether your CLI is up to date.
  • Update from the provider panel.When a newer version is available, select it and use Update to to install it locally.
  • Return to an earlier version.Select a previous release from the available versions. The action changes to Downgrade to, so you can see which version you are about to install.

The captures show a CLI that is already up to date. Selecting an earlier release previews the downgrade action; choosing a version alone does not install it. Version availability follows the list shown in Manage Providers.

INSTALLED & LATESTManage Providers
Codex selected in Manage Providers, with Installed 0.153.4, Latest 0.153.4, Up to date, and the CLI version selector.
Your local CLI and its update status, in one place.
CHOOSE A RELEASEVersion history
The Codex CLI version list expanded in Manage Providers, showing the installed and latest 0.153.4 release alongside earlier versions.
Browse the available versions before choosing a release.
RETURN TO AN EARLIER VERSIONDowngrade
Manage Providers still shows Codex CLI 0.153.4 installed, with 0.153.3 selected and a Downgrade to 0.153.3 button ready.
Choose an earlier release. Review the downgrade action.

04 / Visual Studio context

Start with the code
in front of you.

Bring the relevant code into your Codex conversation from the IDE where you are already working.

  • Add a file with #.Reference the files Codex needs directly from the prompt.
  • Attach the active document or selection.Use the context menu to point the conversation at a file or a specific piece of code.
  • Turn context into a concrete task.Explain a file, find a bug, add tests, or work through a refactor while keeping Visual Studio close at hand.
YOUR NEXT C# TASKAsk Codex
New Codex conversation in iolys with suggested tasks to explain code, fix bugs or add tests, and a prompt with context and model controls.
Your prompt, context, and model in one place.

05 / Native Codex tools

Research the web.
Create the visual.

Codex’s native web search and image generation tools are available in iolys. Research a question or create an image from the same conversation, inside Visual Studio.

WEB SEARCH

Bring documentation into the task.

Ask Codex to search the web and read relevant pages. Use its native web tool to investigate an issue or find documentation while working on your solution.

TRY A PROMPT

“Find the official documentation for this .NET API and explain how it applies to my code.”

IMAGE GENERATION

Turn an idea into an image.

Describe the visual you need and let Codex use its native image generation tool. Create illustrations, mockups, or image assets alongside your development work.

TRY A PROMPT

“Create an illustration for the empty state of my task dashboard.”

And the workflow around your code.

These native tools work alongside the IDE tools and conversation controls built into iolys.

CONVERSATIONS

Pick up where you left off.

Open chat history and return to an earlier task. Keep separate conversations for separate pieces of work.

CUSTOM AGENTS

Keep your specialists close.

Choose an agent with its own instructions and tool access. Reuse a C# reviewer or testing specialist across your work.

Explore custom agents ↗
TOOL ACTIVITY

Follow the work as it happens.

See tool activity and permission requests in the conversation, with changes available for review in your iolys workflow.

CONTEXT WINDOW

Keep long tasks in view.

Check context window usage from the composer. The Codex integration supports automatic context compaction as conversations grow.

Connect Codex

Set up Codex in Manage Providers.

iolys downloads and manages the CLI locally. Keep installation, versions, and updates together inside Visual Studio.

  1. 01

    Open Manage Providers in iolys and select Codex.

  2. 02

    Download the CLI locally from the provider panel, then follow the account sign-in flow. Manage CLI versions and updates in the same place.

  3. 03

    Choose your Codex model and start from the active Visual Studio 2026 solution.

Codex FAQ

Codex and Visual Studio 2026.

Visit the official Codex website ↗
How can I use Codex in Visual Studio for C#?

Install the iolys extension for Visual Studio 2026 and open your C# solution. Open Manage Providers in iolys and select Codex. Download the CLI locally from the provider panel, then follow the account sign-in flow. Manage CLI versions and updates in the same place. Choose your Codex model and start from the active Visual Studio 2026 solution. You can then ask Codex to help with your C# and .NET code from the iolys workspace.

Is there a VSIX extension to use Codex in Visual Studio?

Yes. iolys is a VSIX extension for Visual Studio 2026, and Codex is one of the provider connections it ships with. Install the iolys VSIX once from the Visual Studio Marketplace, then add Codex from the Manage Providers panel; there is no separate VSIX per provider.

Can I use my ChatGPT subscription for Codex in iolys?

Yes. Sign in with your ChatGPT account to use the Codex access included in your eligible subscription inside Visual Studio 2026. Your usage counts toward that plan’s Codex allowance. iolys provides the Visual Studio integration; your provider subscription remains with ChatGPT.

Does Codex work in Visual Studio 2026?

Yes, with the iolys extension. It connects the Codex CLI to a provider-independent workspace built for Visual Studio 2026.

How is the Codex CLI installed and managed?

Open Manage Providers in iolys. The Codex CLI is downloaded and managed locally from this panel, including its versions and updates. You do not need to install it separately before setting up the provider.

Can I update or roll back the Codex CLI?

Yes. In Manage Providers, select Codex to compare the installed and latest CLI versions. Choose a newer available release to update, or an earlier release from the version list to display the Downgrade to action. Selecting a version alone does not install it; you apply the change with the corresponding button.

Do I need an OpenAI API key?

Not necessarily. The Codex CLI can use eligible account-based access; API-key options remain available when that is the route you prefer.

Can I see my Codex usage and banked resets in Visual Studio?

Yes. Open Show usage from the iolys chat toolbar to see the usage percentage, reset times, and available usage resets reported by your Codex account, including their expiration dates. Reset availability depends on your account.

Can I choose the model, reasoning effort, and Fast mode?

Yes. Open the model options beside the prompt. iolys exposes the models, reasoning effort levels, and Fast mode options supported by your Codex connection. Availability depends on the selected model and account; Fast mode can increase usage.

How do I give Codex context from Visual Studio?

Type # to reference a file, or use the context menu to attach the active document or current selection. You can then ask Codex to explain code, investigate a bug, write tests, or help with a refactor.

Can Codex search the web and generate images in iolys?

Yes. The integration supports Codex’s native web search and image generation tools. Ask Codex to research a question, read relevant documentation, or create an image from a description, directly in your Visual Studio conversation. These work alongside the IDE tools provided by iolys.

Can I switch away from Codex later?

Yes. Provider switching is a core iolys workflow, so your Visual Studio 2026 experience remains consistent.

Explore other providers for Visual Studio 2026

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Use Codex for C# and .NET without leaving Visual Studio 2026.

Keep your active solution, provider access, and development workflow.

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