OpenAI Codex CLI error
Codex CLI: Codex process errored: Codex process is not available
Codex process errored: Codex process is not availableStatus: Fixed in releaseLast verified 1 documented fix1 source
What it means
The Codex IDE extension (VS Code) could not talk to its underlying codex app-server process; the output log showed "unable to parse stdout from codex app-server: SyntaxError: Unexpected end of JSON input".
Causes
- Maintainer dylan-hurd-oai (#6435): bugs with the extension's WSL setting on Windows.
How to fix it
- Fix 1.
Install the latest extension pre-release (0.5.39 at the time) or turn off the WSL setting (maintainer dylan-hurd-oai on #6435).
Snippetchatgpt.runCodexInWindowsSubsystemForLinux
More Codex CLI errors
All 14 Codex CLI errorsstream disconnected before completion: stream closed before response.completedStatus: Workaroundstream disconnected before completion: error sending request for url (https://chatgpt.com/backend-api/codex/responses)Status: OpenError running remote compact task: stream disconnected before completion: error sending request for url (https://chatgpt.com/backend-api/codex/responses/compact)Status: Fixed in releaseSelected model is at capacity. Please try a different model.Status: By designYour access token could not be refreshed because your refresh token was already used. Please log out and sign in again.Status: Fixed in releaseCodex ran out of room in the model's context window. Start a new thread or clear earlier history before retrying.Status: Fixed in releaseError logging in: Port 127.0.0.1:1455 is already in useStatus: WorkaroundToken exchange failed: token endpoint returned status 403 ForbiddenStatus: Workaround
Related reading
- Codex CLI 0.163: Instant Steering Is Now the DefaultCodex CLI 0.163.0 makes mid-response steering the default and adds searchable /config and a leader key. What changed and what to check before upgrading.
- Codex 'gpt-5.5 Model Is Not Supported' Error: The FixCodex says gpt-5.5 is not supported with a ChatGPT account because OpenAI retired it from ChatGPT sign-in on October 14. The fix and what still works.
- Agent Harness Lessons From a 500B-Token Decompile: Give Agents a PASS/FAIL OracleAgent harness lessons from a 500B+ token decompile: a byte-matching PASS/FAIL oracle beat the reviewer agent. How agents cheated it and what to copy.
- Codex CLI Background Daemon: How to Turn It OffCodex CLI starts a persistent, self-updating background daemon since 0.157.0. What it does, why it hit Hacker News and the reported workaround to turn it off.
- Codex CLI 0.162: Managed Worktrees and Pinned TasksCodex CLI 0.162 lets the agent create and list its own Git worktrees, adds pinned tasks and custom provider capability overrides. What to change this week.
- ChatGPT Free vs Go vs Plus After GPT-6: Which Model You GetFree and Go ($8) both get GPT-6 Luna in Chat. Plus ($20) is the cheapest plan with GPT-6 Sol and full Codex. What each ChatGPT plan buys now.
FAQ
What does "Codex process errored: Codex process is not available" mean in Codex CLI?
The Codex IDE extension (VS Code) could not talk to its underlying codex app-server process; the output log showed "unable to parse stdout from codex app-server: SyntaxError: Unexpected end of JSON input".
How do I fix "Codex process errored: Codex process is not available"?
Install the latest extension pre-release (0.5.39 at the time) or turn off the WSL setting (maintainer dylan-hurd-oai on #6435).
Is this Codex CLI error fixed?
Status: Fixed in release. A release fixed this. The affected versions note says where the fix landed. Affected versions: Reported on Windows 10 with the VS Code extension and WSL (#6435); addressed in extension pre-release 0.5.39
Sources
Last verified against 1 source: official docs, maintainer replies and release notes.
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