concepts/customization.md Codex Docs, 2026-04-02 18:23 UTC → 2026-04-20 06:53 UTC

5In Codex, customization comes from a few layers that work together:5In Codex, customization comes from a few layers that work together:

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7- **Project guidance (`AGENTS.md`)** for persistent instructions7- **Project guidance (`AGENTS.md`)** for persistent instructions

8- **[Memories](https://developers.openai.com/codex/memories)** for useful context learned from prior work

8- **Skills** for reusable workflows and domain expertise9- **Skills** for reusable workflows and domain expertise

9- **[MCP](https://developers.openai.com/codex/mcp)** for access to external tools and shared systems10- **[MCP](https://developers.openai.com/codex/mcp)** for access to external tools and shared systems

10- **[Subagents](https://developers.openai.com/codex/concepts/subagents)** for delegating work to specialized subagents11- **[Subagents](https://developers.openai.com/codex/concepts/subagents)** for delegating work to specialized subagents

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12These are complementary, not competing. `AGENTS.md` shapes behavior, skills package repeatable processes, and [MCP](https://developers.openai.com/codex/mcp) connects Codex to systems outside the local workspace.13These are complementary, not competing. `AGENTS.md` shapes behavior, memories

14carry local context forward, skills package repeatable processes, and

15[MCP](https://developers.openai.com/codex/mcp) connects Codex to systems outside the local workspace.

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14## AGENTS Guidance17## AGENTS Guidance

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