cli/features.md Codex Docs, 2026-04-21 18:29 UTC → 2026-05-14 07:00 UTC

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108## Models and reasoning108## Models and reasoning

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110For most tasks in Codex, `gpt-5.4` is the recommended model. It brings the110For most tasks in Codex, `gpt-5.5` is the recommended model when it is

111industry-leading coding capabilities of `gpt-5.3-codex` to OpenAI’s flagship111available. It is OpenAI's newest frontier model for complex coding, computer

112frontier model, combining frontier coding performance with stronger reasoning,112use, knowledge work, and research workflows, with stronger planning, tool use,

113native computer use, and broader professional workflows. For extra fast tasks,113and follow-through on multi-step tasks. If `gpt-5.5` is not yet available,

114ChatGPT Pro subscribers have access to the GPT-5.3-Codex-Spark model in114continue using `gpt-5.4`. For extra fast tasks, ChatGPT Pro subscribers have

115research preview.115access to the GPT-5.3-Codex-Spark model in research preview.

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117Switch models mid-session with the `/model` command, or specify one when launching the CLI.117Switch models mid-session with the `/model` command, or specify one when launching the CLI.

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119```bash119```bash

120codex --model gpt-5.4120codex --model gpt-5.5

121```121```

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123[Learn more about the models available in Codex](https://developers.openai.com/codex/models).123[Learn more about the models available in Codex](https://developers.openai.com/codex/models).

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163You can ask in natural language or explicitly invoke the image generation skill by including `$imagegen` in your prompt.163You can ask in natural language or explicitly invoke the image generation skill by including `$imagegen` in your prompt.

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165Built-in image generation uses `gpt-image-1.5`, counts toward your general Codex usage limits, and uses included limits 3-5x faster on average than similar turns without image generation, depending on image quality and size. For details, see [Pricing](https://developers.openai.com/codex/pricing#image-generation-usage-limits). For prompting tips and model details, see the [image generation guide](https://developers.openai.com/api/docs/guides/image-generation).165Built-in image generation uses `gpt-image-2`, counts toward your general Codex usage limits, and uses included limits 3-5x faster on average than similar turns without image generation, depending on image quality and size. For details, see [Pricing](https://developers.openai.com/codex/pricing#image-generation-usage-limits). For prompting tips and model details, see the [image generation guide](https://developers.openai.com/api/docs/guides/image-generation).

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167For larger batches of image generation, set `OPENAI_API_KEY` in your environment variables and ask Codex to generate images through the API so API pricing applies instead.167For larger batches of image generation, set `OPENAI_API_KEY` in your environment variables and ask Codex to generate images through the API so API pricing applies instead.

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255## Slash commands255## Slash commands

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257Slash commands give you quick access to specialized workflows like `/review`, `/fork`, or your own reusable prompts. Codex ships with a curated set of built-ins, and you can create custom ones for team-specific tasks or personal shortcuts.257Slash commands give you quick access to specialized workflows like `/review`, `/fork`, `/side`, or your own reusable prompts. Codex ships with a curated set of built-ins, and you can create custom ones for team-specific tasks or personal shortcuts.

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259See the [slash commands guide](https://developers.openai.com/codex/guides/slash-commands) to browse the catalog of built-ins, learn how to author custom commands, and understand where they live on disk.259See the [slash commands guide](https://developers.openai.com/codex/guides/slash-commands) to browse the catalog of built-ins, learn how to author custom commands, and understand where they live on disk.

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