core-agent-ide/docs/config.md
Josh McKinney 6912da84a8
client: extend custom CA handling across HTTPS and websocket clients (#14239)
## Stacked PRs

This work is now effectively split across two steps:

- #14178: add custom CA support for browser and device-code login flows,
docs, and hermetic subprocess tests
- #14239: extend that shared custom CA handling across Codex HTTPS
clients and secure websocket TLS

Note: #14240 was merged into this branch while it was stacked on top of
this PR. This PR now subsumes that websocket follow-up and should be
treated as the combined change.

Builds on top of #14178.

## Problem

Custom CA support landed first in the login path, but the real
requirement is broader. Codex constructs outbound TLS clients in
multiple places, and both HTTPS and secure websocket paths can fail
behind enterprise TLS interception if they do not honor
`CODEX_CA_CERTIFICATE` or `SSL_CERT_FILE` consistently.

This PR broadens the shared custom-CA logic beyond login and applies the
same policy to websocket TLS, so the enterprise-proxy story is no longer
split between “HTTPS works” and “websockets still fail”.

## What This Delivers

Custom CA support is no longer limited to login. Codex outbound HTTPS
clients and secure websocket connections can now honor the same
`CODEX_CA_CERTIFICATE` / `SSL_CERT_FILE` configuration, so enterprise
proxy/intercept setups work more consistently end-to-end.

For users and operators, nothing new needs to be configured beyond the
same CA env vars introduced in #14178. The change is that more of Codex
now respects them, including websocket-backed flows that were previously
still using default trust roots.

I also manually validated the proxy path locally with mitmproxy using:
`CODEX_CA_CERTIFICATE=~/.mitmproxy/mitmproxy-ca-cert.pem
HTTPS_PROXY=http://127.0.0.1:8080 just codex`
with mitmproxy installed via `brew install mitmproxy` and configured as
the macOS system proxy.

## Mental model

`codex-client` is now the owner of shared custom-CA policy for outbound
TLS client construction. Reqwest callers start from the builder
configuration they already need, then pass that builder through
`build_reqwest_client_with_custom_ca(...)`. Websocket callers ask the
same module for a rustls client config when a custom CA bundle is
configured.

The env precedence is the same everywhere:
- `CODEX_CA_CERTIFICATE` wins
- otherwise fall back to `SSL_CERT_FILE`
- otherwise use system roots

The helper is intentionally narrow. It loads every usable certificate
from the configured PEM bundle into the appropriate root store and
returns either a configured transport or a typed error that explains
what went wrong.

## Non-goals

This does not add handshake-level integration tests against a live TLS
endpoint. It does not validate that the configured bundle forms a
meaningful certificate chain. It also does not try to force every
transport in the repo through one abstraction; it extends the shared CA
policy across the reqwest and websocket paths that actually needed it.

## Tradeoffs

The main tradeoff is centralizing CA behavior in `codex-client` while
still leaving adoption up to call sites. That keeps the implementation
additive and reviewable, but it means the rule "outbound Codex TLS that
should honor enterprise roots must use the shared helper" is still
partly enforced socially rather than by types.

For websockets, the shared helper only builds an explicit rustls config
when a custom CA bundle is configured. When no override env var is set,
websocket callers still use their ordinary default connector path.

## Architecture

`codex-client::custom_ca` now owns CA bundle selection, PEM
normalization, mixed-section parsing, certificate extraction, typed
CA-loading errors, and optional rustls client-config construction for
websocket TLS.

The affected consumers now call into that shared helper directly rather
than carrying login-local CA behavior:
- backend-client
- cloud-tasks
- RMCP client paths that use `reqwest`
- TUI voice HTTP paths
- `codex-core` default reqwest client construction
- `codex-api` websocket clients for both responses and realtime
websocket connections

The subprocess CA probe, env-sensitive integration tests, and shared PEM
fixtures also live in `codex-client`, which is now the actual owner of
the behavior they exercise.

## Observability

The shared CA path logs:
- which environment variable selected the bundle
- which path was loaded
- how many certificates were accepted
- when `TRUSTED CERTIFICATE` labels were normalized
- when CRLs were ignored
- where client construction failed

Returned errors remain user-facing and include the relevant env var,
path, and remediation hint. That same error model now applies whether
the failure surfaced while building a reqwest client or websocket TLS
configuration.

## Tests

Pure unit tests in `codex-client` cover env precedence and PEM
normalization behavior. Real client construction remains in subprocess
tests so the suite can control process env and avoid the macOS seatbelt
panic path that motivated the hermetic test split.

The subprocess coverage verifies:
- `CODEX_CA_CERTIFICATE` precedence over `SSL_CERT_FILE`
- fallback to `SSL_CERT_FILE`
- single-cert and multi-cert bundles
- malformed and empty-file errors
- OpenSSL `TRUSTED CERTIFICATE` handling
- CRL tolerance for well-formed CRL sections

The websocket side is covered by the existing `codex-api` / `codex-core`
websocket test suites plus the manual mitmproxy validation above.

---------

Co-authored-by: Ivan Zakharchanka <3axap4eHko@gmail.com>
Co-authored-by: Codex <noreply@openai.com>
2026-03-13 00:59:26 +00:00

3.7 KiB

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.

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