What is Codex?

Codex is OpenAI's coding agent. It can work with files, run commands and collaborate through its app or CLI.

Process: CodexAlso seen as: codexMade by OpenAIApplies to: Codex desktop and CLI on macOS. Behavior depends on the version, sign-in method and task.Checked: 3 November 2026

Short answer

OpenAI's coding agent, available as a desktop app, command-line tool and other interfaces.

Block with care

Blocking Codex may interrupt model requests, integrations and tasks that need network access.

Path
/Applications/Codex.app/Contents/MacOS/Codex

What it is

OpenAI describes Codex as a coding agent available in a desktop app, CLI, IDE extensions and other interfaces.

Codex communicates with OpenAI services to run model requests. Its exact connection pattern can vary by task.

Codex can also use tools and execute commands. Those commands may start their own processes or make network requests.

Kilobat identifies a process using operating-system information. A matching name alone does not prove who made an executable.

Why it uses the network

  • Model requests. The agent exchanges requests and responses with its service while working on a task.
  • Tools and integrations. A task can involve websites, package registries, source repositories or other services through tools and commands.
  • File transfers. A task may require sending context or downloading content, depending on what you ask it to do.

How much is normal

Traffic varies with the task, its tools and context. A single universal normal amount is not meaningful.

An active upload shows bytes sent, not their contents. Kilobat cannot infer encrypted content from its size alone.

Even a task that looks idle can continue waiting for a command or a response. Check the task before stopping it.

When it uses a lot, and why

  • Large task context. A task involving many files or large attachments can produce more traffic than a short exchange.
  • Downloads and integrations. A command that fetches dependencies, repositories or external resources can create additional traffic.

Is it safe to block?

Block with care

Blocking Codex may interrupt model requests, integrations and tasks that need network access.

What breaks if you block it

  • Active work requiring network requests can fail or pause.
  • Commands that depend on network resources may not finish as expected.
  • Local files are separate from the network connection. Blocking access does not itself erase those files.

Blocking means a firewall rule that refuses its connections. Don’t quit or disable a macOS process to save data: macOS starts it again, and other features depend on it.

Reduce its use

  1. Stop or pause a task you no longer need from the Codex interface.

  2. Review the active connection list to see which process uses data before changing any rule.

  3. On a limited connection, avoid asking for unnecessary downloads or large transfers.

  4. Check the activity and permissions of integrations involved in the task before running it again.

See how much it uses

  1. Open Activity Monitor from Applications › Utilities. Click Network.

  2. Type Codex in the search field. The Sent Bytes and Rcvd Bytes columns show what it moved since it started.

  3. In Terminal, watch only this process. Press d to show the change per second, and q to quit.

    nettop -p 'Codex' -P

With Kilobat

  1. Inspect Codex's connections and their destinations to understand where traffic is going.

  2. Search for Codex in the app list to see its rate and attributed data.

  3. Ask the CLI for this explanation.

    kilobat explain codex

The live view and the explanations are free. History in the app needs Kilobat Pro. Blocking needs Pro and the network filter: see the network filter, Protection and the hotspot data saver.

Hosts it contacts

Apple and the maker document these hosts for this feature. A process can also contact others; Kilobat’s Connections tab shows what it actually opens on your Mac.

chatgpt.comOpenAI's ChatGPT website and a backend used by Codex when signed in with ChatGPT.OpenAI →api.openai.comThe OpenAI API endpoint used by applications making API requests.OpenAI →

Questions

Does an upload mean Codex is sending my entire computer?

No. The upload count shows bytes, not which files or content were sent. Review your task and tool settings for context.

Is every connection to a new destination dangerous?

No. Tasks and integrations can use many destinations. A new destination alone does not establish malicious behavior.

Does blocking Codex block every other app using OpenAI?

No. A process rule and a host rule have different scopes. Other apps may connect to the same service.

Does Kilobat inspect my encrypted prompts?

These connection facts describe destinations and transferred bytes. They do not establish the contents of encrypted traffic.

Sources

Checked on 3 November 2026.