ChatGPT Manual

Subagent

A subagent takes a slice of a Codex task. It is configuration, not a second subscription. Limits are still your plan's Codex limits.

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What the word means here

Subagent is the search for a helper agent that a main Codex agent can call. OpenAI documents it under agent configuration. The parent task splits work: one subagent reads tests, another edits a module, and the parent assembles the result. You are not buying a separate seat for each one.

Every call draws on the Codex allowance. Four subagents do not multiply your plan by four. They spend the shared window faster. Start with one delegated step if you are watching the usage meter.

How to scope one

Give the subagent a folder, a done test, and a ban on unrelated refactors. A subagent with 'clean up the repo' will wander. The official configuration page is the syntax source. Copy from there, not from a memory of last month's YAML, because the fields move.

A Codex goal can be the parent. The subagent is the division of labor inside it. Neither one removes the need to read the diff.

Questions

Is a subagent a custom GPT?
No. Custom GPTs are saved chats in ChatGPT. Subagents are part of Codex agent configuration.
Do subagents cost extra?
They consume the Codex usage included in your plan, and credits if you exceed it. There is not a per-subagent price on the pricing page.
Where is the official setup?
OpenAI's docs at chatgpt.com/docs/agent-configuration/subagents. This page is the plain-language map, not a second spec.

Related guides

Sources

Checked 2026-09-25. Prices, limits, and model names can change on the live pages.