## Why The earlier PRs add stdio transport support and the config-backed environment provider, but the feature remains inert until normal Codex entrypoints construct `EnvironmentManager` with enough context to discover `CODEX_HOME/environments.toml`. This final stack PR activates the provider while preserving the legacy `CODEX_EXEC_SERVER_URL` fallback when no environments file exists. **Stack position:** this is PR 5 of 5. It is the product wiring PR that activates the configured environment provider added in PR 4. ## What Changed - Thread `codex_home` into `EnvironmentManagerArgs`. - Change `EnvironmentManager::new(...)` to load the provider from `CODEX_HOME`. - Preserve legacy behavior by falling back to `DefaultEnvironmentProvider::from_env()` when `environments.toml` is absent. - Make `environments.toml`-backed managers start new threads with all configured environments, default first, while keeping the legacy env-var path single-default. - Update the app-server, TUI, exec, MCP server, connector, prompt-debug, and thread-manager-sample callsites to pass `codex_home` and handle provider-loading errors. ## Self-Review Notes - The multi-environment startup path is intentionally tied to the `environments.toml` provider. Using `>1` configured environment as the only signal would also expand the legacy `CODEX_EXEC_SERVER_URL` provider because it keeps `local` addressable alongside `remote`. - The startup environment list is still derived inside `EnvironmentManager`; the provider only says whether its snapshot should start new threads with all configured environments. - The thread-manager sample was updated to pass the current `ThreadManager::new(...)` installation id argument so the stack compiles under Bazel. ## Stack - 1. https://github.com/openai/codex/pull/20663 - Add stdio exec-server listener - 2. https://github.com/openai/codex/pull/20664 - Add stdio exec-server client transport - 3. https://github.com/openai/codex/pull/20665 - Make environment providers own default selection - 4. https://github.com/openai/codex/pull/20666 - Add CODEX_HOME environments TOML provider - **5. This PR:** https://github.com/openai/codex/pull/20667 - Load configured environments from CODEX_HOME Split from original draft: https://github.com/openai/codex/pull/20508 ## Validation - `just fmt` - `git diff --check` - `bazel build --config=remote --strategy=remote --remote_download_toplevel //codex-rs/thread-manager-sample:codex-thread-manager-sample` - `bazel test --config=remote --strategy=remote --remote_download_toplevel //codex-rs/exec-server:exec-server-unit-tests` - `bazel test --config=remote --strategy=remote --remote_download_toplevel --test_sharding_strategy=disabled --test_arg=default_thread_environment_selections_use_manager_default_id //codex-rs/core:core-unit-tests` - `bazel test --config=remote --strategy=remote --remote_download_toplevel --test_sharding_strategy=disabled --test_arg=start_thread_uses_all_default_environments_from_codex_home //codex-rs/core:core-unit-tests` ## Documentation This activates `CODEX_HOME/environments.toml`; user-facing documentation should be added before this stack is treated as a documented public workflow. --------- Co-authored-by: Codex <noreply@openai.com>
codex-app-server-client
Shared in-process app-server client used by conversational CLI surfaces:
codex-execcodex-tui
Purpose
This crate centralizes startup and lifecycle management for an in-process
codex-app-server runtime, so CLI clients do not need to duplicate:
- app-server bootstrap and initialize handshake
- in-memory request/event transport wiring
- lifecycle orchestration around caller-provided startup identity
- graceful shutdown behavior
Startup identity
Callers pass both the app-server SessionSource and the initialize
client_info.name explicitly when starting the facade.
That keeps thread metadata (for example in thread/list and thread/read)
aligned with the originating runtime without baking TUI/exec-specific policy
into the shared client layer.
Transport model
The in-process path uses typed channels:
- client -> server:
ClientRequest/ClientNotification - server -> client:
InProcessServerEventServerRequestServerNotificationLegacyNotification
JSON serialization is still used at external transport boundaries (stdio/websocket), but the in-process hot path is typed.
Typed requests still receive app-server responses through the JSON-RPC result envelope internally. That is intentional: the in-process path is meant to preserve app-server semantics while removing the process boundary, not to introduce a second response contract.
Bootstrap behavior
The client facade starts an already-initialized in-process runtime, but thread bootstrap still follows normal app-server flow:
- caller sends
thread/startorthread/resume - app-server returns the immediate typed response
- richer session metadata may arrive later as a
SessionConfiguredlegacy event
Surfaces such as TUI and exec may therefore need a short bootstrap phase where they reconcile startup response data with later events.
Backpressure and shutdown
- Queues are bounded and use
DEFAULT_IN_PROCESS_CHANNEL_CAPACITYby default. - Full queues return explicit overload behavior instead of unbounded growth.
shutdown()performs a bounded graceful shutdown and then aborts if timeout is exceeded.
If the client falls behind on event consumption, the worker emits
InProcessServerEvent::Lagged and may reject pending server requests so
approval flows do not hang indefinitely behind a saturated queue.