For basic configuration instructions, see this documentation.
For advanced configuration instructions, see this documentation.
For a full configuration reference, see this documentation.
Codex can connect to MCP servers configured in ~/.codex/config.toml. See the configuration reference for the latest MCP server options:
Use $ in the composer to insert a ChatGPT connector; the popover lists accessible
apps. The /apps command lists available and installed apps. Connected apps appear first
and are labeled as connected; others are marked as can be installed.
Codex can run a notification hook when the agent finishes a turn. See the configuration reference for the latest notification settings:
When Codex knows which client started the turn, the legacy notify JSON payload also includes a top-level client field. The TUI reports codex-tui, and the app server reports the clientInfo.name value from initialize.
The generated JSON Schema for config.toml lives at codex-rs/core/config.schema.json.
Codex stores the SQLite-backed state DB under sqlite_home (config key) or the
CODEX_SQLITE_HOME environment variable. When unset, WorkspaceWrite sandbox
sessions default to a temp directory; other modes default to CODEX_HOME.
Codex can trust a custom root CA bundle for outbound HTTPS and secure websocket
connections when enterprise proxies or gateways intercept TLS. This applies to
login flows and to Codex's other external connections, including Codex
components that build reqwest clients or secure websocket clients through the
shared codex-client CA-loading path and remote MCP connections that use it.
Set CODEX_CA_CERTIFICATE to the path of a PEM file containing one or more
certificate blocks to use a Codex-specific CA bundle. If
CODEX_CA_CERTIFICATE is unset, Codex falls back to SSL_CERT_FILE. If
neither variable is set, Codex uses the system root certificates.
CODEX_CA_CERTIFICATE takes precedence over SSL_CERT_FILE. Empty values are
treated as unset.
The PEM file may contain multiple certificates. Codex also tolerates OpenSSL
TRUSTED CERTIFICATE labels and ignores well-formed X509 CRL sections in the
same bundle. If the file is empty, unreadable, or malformed, the affected Codex
HTTP or secure websocket connection reports a user-facing error that points
back to these environment variables.
Codex stores "do not show again" flags for some UI prompts under the [notice] table.
plan_mode_reasoning_effort lets you set a Plan-mode-specific default reasoning
effort override. When unset, Plan mode uses the built-in Plan preset default
(currently medium). When explicitly set (including none), it overrides the
Plan preset. The string value none means "no reasoning" (an explicit Plan
override), not "inherit the global default". There is currently no separate
config value for "follow the global default in Plan mode".
experimental_realtime_start_instructions lets you replace the built-in
developer message Codex inserts when realtime becomes active. It only affects
the realtime start message in prompt history and does not change websocket
backend prompt settings or the realtime end/inactive message.
Ctrl+C/Ctrl+D quitting uses a ~1 second double-press hint (ctrl + c again to quit).