Memories - what Codex can carry from one chat into the next

You told Codex on Monday that budgetcli keeps money as integer cents and that the test command is pytest -q. On Wednesday you open a new chat and it asks again. AGENTS.md fixes that for facts you decide to write down. Memories are the other route: Codex distils earlier chats into notes and loads them into later ones, so recall does not depend on you remembering to write the fact down.

This lesson is sourced from the OpenAI docs and the installed CLI, not from a captured run. Memories are off by default, and the docs page does not give them a maturity label. The local codex features list (codex-cli 0.163.0, checked 2026-10-25) shows the memories flag as stable, default false. Treat “stable flag, opt-in” as the verified state and nothing stronger.

Memories are a recall layer, not a rulebook

The docs say it plainly: keep required team guidance in AGENTS.md or checked-in documentation, because memories are a recall layer and not the only source for rules that must always apply. The difference is who controls the content.

	AGENTS.md	Memories
Written by	You, reviewed in a pull request	Codex, generated from earlier chats
Shared with the team	Yes, it is in the repo	No, it is local to your Codex home
Predictable	Loaded the same way every session	Depends on what earlier chats contained
Right for	Conventions that must hold	Preferences and context you would otherwise retype

A convention you would be unhappy to see missing belongs in AGENTS.md. A habit of yours that you are tired of restating can live in memory.

Turn them on

In config.toml:

[features]
memories = true

The desktop app has the equivalent switch under Settings > Personalization (Enable Codex memories). Both are from the memories docs page, https://learn.chatgpt.com/docs/customization/memories, read 2026-10-25.

Generated state lives under your Codex home, which defaults to ~/.codex, in ~/.codex/memories/. The docs describe the files as summaries, durable entries, recent inputs and supporting evidence, and treat them as generated state rather than something to hand-edit. Memories also do not update the moment a chat ends: Codex waits until the chat is idle.

The settings that matter

The docs list these keys under [memories]. They give no default values for them, so check your own behaviour before relying on one.

Key	What it controls
generate_memories	Whether new chats can become inputs for memory generation
use_memories	Whether existing memories are injected into future sessions
disable_on_external_context	When true, chats that used MCP tool calls, web search or tool search are excluded from generation
min_rate_limit_remaining_percent	Minimum remaining rate-limit percentage needed before a generation pass starts
extract_model	Overrides the model that extracts memory from each chat
consolidation_model	Overrides the model that consolidates memory globally

disable_on_external_context is the one to think about on a work repo. A chat that pulled in a Jira ticket through MCP or a web page through search has third-party text in it; excluding those chats keeps that text out of your long-term notes. The older name no_memories_if_mcp_or_web_search is still accepted as an alias.

Per-chat control with /memories

Inside an interactive session, /memories sets two things for the current chat only: whether this chat uses existing memories, and whether it can generate new ones. Neither choice changes your global settings. Use it when a chat is a disposable experiment you do not want remembered, or when you want to check an answer without remembered context influencing it.

What the docs say is skipped

• Active or short-lived sessions.
• Chats that used external context, when disable_on_external_context is true.
• A generation pass when the rate-limit threshold is not met.

Secrets are redacted from generated memory fields, and the docs say not to store secrets in memories. The docs page does not list other exclusions, so do not assume anything beyond this.

Resetting

The desktop app has a Delete Codex memories action that resets the memory store of the selected machine, and on a local machine also clears Computer History when that feature is available. The docs page names no CLI command for it. Because the files are plain generated state under ~/.codex/memories/, inspect them before you decide whether a reset is worth it.

Related

• Resume restores one specific conversation; memory carries distilled facts across all of them.
• The foundations Rules chapter covers why agent-managed memory is a different primitive from a human-written rules file.