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codex/docs/config.md
2026-03-17 23:49:28 -07:00

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Configuration

For basic configuration instructions, see this documentation.

For advanced configuration instructions, see this documentation.

For a full configuration reference, see this documentation.

Connecting to MCP servers

Codex can connect to MCP servers configured in ~/.codex/config.toml. See the configuration reference for the latest MCP server options:

Apps (Connectors)

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.

Notify

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.

JSON Schema

The generated JSON Schema for config.toml lives at codex-rs/core/config.schema.json.

SQLite State DB

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.

Custom CA Certificates

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.

Notices

Codex stores "do not show again" flags for some UI prompts under the [notice] table.

Plan mode defaults

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".

Realtime start instructions

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.

Unified exec over exec-server

experimental_unified_exec_use_exec_server routes unified-exec process launches and filesystem-backed tools through codex-exec-server instead of using only the local in-process implementations.

When experimental_unified_exec_exec_server_websocket_url is set, Codex connects to that existing websocket endpoint and uses it for both unified-exec processes and remote filesystem operations such as read_file, list_dir, and view_image.

When experimental_unified_exec_exec_server_workspace_root is also set, Codex remaps remote exec cwd values and remote filesystem tool paths from the local session cwd root into that executor-visible workspace root. Use this when the executor is running on another host and cannot see the laptop's absolute paths.

When experimental_unified_exec_spawn_local_exec_server is also enabled, Codex starts a session-scoped local codex-exec-server subprocess on startup and uses that connection for the same process and filesystem calls.

experimental_supported_tools can be used to opt specific experimental tools into the tool list even when the selected model catalog entry does not advertise them. This is useful when testing remote filesystem-backed tools such as read_file and list_dir against an exec-server-backed environment.

Ctrl+C/Ctrl+D quitting uses a ~1 second double-press hint (ctrl + c again to quit).