## Summary
Introduces the default-off `respect_system_proxy` feature flag used to
gate first-class system PAC/proxy support for Codex-owned native
clients.
With the feature disabled or absent, behavior remains unchanged. This PR
establishes the configuration and managed-requirement surface; proxy
discovery and request routing are implemented by follow-up PRs.
## Configuration
User configuration uses the standard boolean feature form:
```toml
[features]
respect_system_proxy = true
```
Managed feature requirements use the corresponding boolean key. The
effective runtime configuration is exposed as a boolean and defaults to
`false`.
## Implementation
- Registers `respect_system_proxy` as an under-development, default-off
feature.
- Resolves user configuration and managed feature requirements into
`Config.respect_system_proxy`.
- Provides bootstrap resolution for startup paths that must evaluate the
feature before full configuration loading completes.
- Uses the standard feature CLI and config-editing behavior.
- Excludes `features.respect_system_proxy` from project-local
configuration.
- Updates the generated configuration schema.
## End-user behavior
- No networking behavior changes when the feature is absent or disabled.
- Enabling the feature makes the boolean available to the native
proxy-routing implementation in follow-up PRs.
- Repository-local configuration cannot enable the feature.
## Test coverage
Covers scalar configuration and CLI override resolution, managed
requirement constraints, bootstrap resolution, and project-local
filtering.
## Why
`fs/readFile` buffers the entire file in one response, which makes large
remote reads expensive and prevents callers from applying backpressure.
We need an opt-in streaming path with bounded block sizes while
preserving the existing single-call API for small and sandboxed reads.
## What changed
- Add `ExecServerClient::stream`, returning a named `FileReadStream`
that implements `futures::Stream` and yields immutable 1 MiB byte
blocks.
- Add internal `fs/open`, `fs/readBlock`, and `fs/close` RPCs.
`fs/readBlock` accepts an explicit offset and length.
- Keep unsandboxed files open between block reads, cap open handles per
connection, and clean them up on EOF, error, stream drop, explicit
close, or connection shutdown.
- Reject platform-sandboxed streaming opens instead of turning the
one-shot sandbox helper into a persistent server. Existing `fs/readFile`
behavior is unchanged.
## Testing
- `just test -p codex-exec-server`
- Integration coverage for 1 MiB chunking, exact block-boundary EOF,
sandbox rejection, and continued reads from the opened file after path
replacement.
- Handle-manager coverage for non-sequential offsets, variable block
lengths, the 128-handle limit, and capacity release after close.
## Why
`PathUri::from_abs_path` can fail for absolute paths that do not have a
normal `file:` URI representation, forcing filesystem call sites to
handle a conversion error even though the original path can be preserved
losslessly.
## What
Make `from_abs_path` infallible and migrate its callers. Unrepresentable
paths use `file:///%00/bad/path/<base64>`, encoding Unix bytes or
Windows UTF-16LE; `to_abs_path` validates and decodes that fallback. The
leading encoded null reserves a namespace that cannot collide with a
real Unix or Windows path, and fallback URIs remain opaque to lexical
path operations.
## Validation
Added path-URI coverage for Unix null and non-UTF-8 paths, Windows
device/verbatim and non-Unicode paths, serialization, malformed
fallbacks, opaque lexical operations, invalid native payloads, and
literal `/bad/path` collision resistance.
## Summary
Adds a `RealtimeConversationArchitecture` option for realtime
conversation startup, with `realtimeapi` as the default and `avas` as an
opt-in architecture.
The AVAS path is limited to realtime v1 conversational WebRTC starts,
and WebRTC call creation appends `intent=quicksilver&architecture=avas`
to `/v1/realtime/calls`. The existing sideband websocket still joins by
`call_id`.
This also exposes the per-session architecture override through
app-server v2 `thread/realtime/start` params and updates the config
schema for `[realtime].architecture`.
## Validation
- `just fmt`
- `just write-config-schema`
- `just test -p codex-api sends_avas_session_call_query_params`
- `just test -p codex-core -E
'test(~conversation_webrtc_start_uses_avas_architecture_query)'`
- `just test -p codex-core -E 'test(realtime_loads_from_config_toml)'`
- `just test -p codex-app-server-protocol -E
'test(~serialize_thread_realtime_start) |
test(generated_ts_optional_nullable_fields_only_in_params)'`
- `just test -p codex-app-server -E
'test(realtime_webrtc_start_emits_sdp_notification)'`
## Why
First-party async traits should expose their `Send` contracts explicitly
without requiring `async_trait`. This completes the migration pattern
established in #27303 and #27304.
## What changed
- Replaced the remaining first-party `async_trait` traits with native
return-position `impl Future + Send` where statically dispatched and
explicit boxed `Send` futures where object safety is required.
- Kept implementations behavior-preserving, outlining existing async
bodies into inherent methods where that keeps the diff reviewable.
- Removed all direct first-party `async-trait` dependencies and the
workspace dependency declaration.
- Added a cargo-deny policy that permits `async-trait` only through the
remaining transitive wrapper crates.
- Updated `rand` from 0.8.5 to 0.8.6 to resolve RUSTSEC-2026-0097 and
keep the full cargo-deny check passing.
## Validation
- `just test -p codex-exec-server`: 216 passed, 2 skipped.
- `just test -p codex-model-provider`: 39 passed.
- `just test -p codex-core` and `just test`: changed tests passed;
remaining failures are environment-sensitive suites unrelated to this
migration.
- `cargo deny check`
- `just fix`
- `just fmt`
- `cargo shear`
- `just bazel-lock-check`
## Why
We're moving exec-server to use PathUri for its internal path
representations.
## What
Move `ExecutorFileSystem` APIs to use `PathUri` instead of
`AbsolutePathBuf`. Future changes will convert higher-level parts of
exec-server.
## Why
Auto Review should remain the effective approval reviewer when settings
cross runtime boundaries. A config or app-server round trip must not
change the reviewer identity, and delegated work must not silently fall
back to user review.
This requires both a stable canonical serialized value and propagation
of the effective setting. `auto_review` is the canonical value across
protocol and app-server output, while `guardian_subagent` remains
accepted as backward-compatible input.
## What changed
- serialize `ApprovalsReviewer::AutoReview` consistently as
`auto_review` across core protocol and app-server v2
- continue accepting `guardian_subagent` when reading existing config or
client requests
- carry the active turn's approval reviewer into spawned agents
- update config/debug expectations and add delegated-task regression
coverage
## Scope
This does not change Guardian policy or remove compatibility with
existing `guardian_subagent` inputs. It preserves the selected reviewer
across serialization, config reloads, app-server settings, and delegated
task setup.
Related Guardian changes are split independently:
- #26231 adds denials and soft denials
- #26334 retries transient reviewer failures
- #26333 reuses narrowly scoped low-risk approvals
- #26232 adds TUI denial recovery
## Validation
- `just test -p codex-app-server-protocol` (224 passed)
- regression coverage for delegated task reviewer propagation
- serialization coverage for canonical `auto_review` output and legacy
`guardian_subagent` input
---------
Co-authored-by: saud-oai <saud@openai.com>
## Summary
- Adapts the moved `codex-cloud-config` crate from the legacy cloud
requirements endpoint to the new config bundle endpoint.
- Switches runtime consumers from `CloudRequirementsLoader` to
`CloudConfigBundleLoader` so one shared bundle supplies cloud-delivered
config and requirements.
- Removes the legacy cloud requirements domain loader path.
## Details
This intentionally keeps `codex-cloud-config` monolithic for review
lineage: the previous PR establishes the crate move, and this PR shows
the behavior change against that moved implementation. A follow-up PR
splits the module back into focused files.
The new bundle path preserves the important cloud requirements loader
semantics where intended: account-scoped signed cache, 30 minute TTL, 5
minute refresh cadence, retry/backoff, auth recovery, and fail-closed
startup loading. The cached payload changes from a single requirements
TOML string to the backend-delivered bundle, and validation rejects
malformed config or requirements fragments before cache write/use.
## Summary
- add executor filesystem canonicalization as a bound-path operation
- route remote canonicalization through the exec-server filesystem RPC
surface
- keep path normalization attached to the filesystem that owns the path
## Stack
- 2/5 in the skills path authority stack extracted from
https://github.com/openai/codex/pull/25098
- follows merged https://github.com/openai/codex/pull/25121
## Validation
- `cd
/Users/starr/code/codex-worktrees/pr-25098-restack-review-pr1b/codex-rs
&& just fmt`
- Not run: tests/checks (not requested)
- GitHub CI pending on rewritten head
## Summary
PR 3 of 5 in the cloud-managed config client stack.
Adds enterprise-managed cloud config as a first-class config layer
source. The layer metadata is preserved through config loading,
diagnostics, debug output, hook attribution, and app-server protocol
surfaces.
## Details
- Enterprise-managed config becomes a normal config layer source with
backend-supplied `id` and display `name` attached for provenance.
- These layers are designed to behave like non-file managed config: they
can surface syntax/type diagnostics by layer name even though there is
no physical config file.
- Relative path settings are resolved from a stored config base so
cloud-delivered config remains consistent with existing MDM-delivered
config semantics.
- Hook attribution distinguishes config-delivered hooks from
requirements-delivered hooks via `HookSource::CloudManagedConfig`.
- This remains pull-based and snapshot-oriented; the PR adds layer
identity/diagnostics, not dynamic reload behavior.
## Validation
Validated through the targeted stack checks after rebasing onto current
`main`:
- Rust crate tests for
config/hooks/cloud-config/backend-client/app-server-protocol
- Filtered `codex-core` and `codex-app-server` `cloud_config_bundle`
tests
- Python generated-file contract test
- `cargo shear --deny-warnings`
- Targeted `argument-comment-lint` for config/hooks
## Summary
- Bump the workspace Rust toolchain from `1.93.0` to `1.95.0` across
Cargo, Bazel, CI, release workflows, devcontainers, and the Codex
environment config.
- Refresh `MODULE.bazel.lock` so the Bazel Rust toolchain artifacts
match the new version.
- Leave purpose-specific toolchains unchanged, including the
`argument-comment-lint` nightly and the upstream `rusty_v8` `1.91.0`
build pin.
- Includes fixes for new lints from `just fix` and a few codex-authored
fixes for lints without a suggestion.
## Why
`--profile` now selects `<name>.config.toml`, so the legacy `profile`
selector should not be reintroduced through config write or MCP tool
paths. A matching legacy selector in base user config also needs the
same migration guard as a matching legacy `[profiles.<name>]` table so
profile loading fails with one clear migration error instead of mixing
the old and new profile models.
## What
- reject non-null app-server config writes to the top-level legacy
`profile` selector
- make `--profile <name>` reject base user config that still selects the
same legacy `profile = "<name>"` value, alongside the existing matching
legacy profile-table guard
- reject removed MCP `codex` tool fields such as `profile` by denying
unknown tool-call parameters and exposing that restriction in the
generated schema
- add regression coverage for the app-server write paths, config loader
guard, and MCP tool input/schema behavior
## Verification
- targeted regression tests cover the new app-server, config loader, and
MCP rejection paths
This adds `apps_mcp_product_sku` as a toplevel config.toml key. We pass
the given value as a header when listing MCPs for the client, allowing
connectors to be filtered per product entry point.
---------
Co-authored-by: Codex <noreply@openai.com>
## Why
`profile-v2` layers the selected profile file on top of the base user
`config.toml`, but the legacy `[profiles]` table also stores named
profile overrides in that same base file. Allowing both paths during one
load makes it too easy to get a mixed profile where stale legacy
settings still influence a profile-v2 run.
## What Changed
- Detect a legacy `[profiles]` table in the base user config whenever
`--profile-v2` selects a profile file.
- Fail config loading with an `InvalidData` error that tells the user to
move those settings into the selected profile-v2 file or remove
`[profiles]`.
- Add a loader regression covering `--profile-v2` with legacy
`[profiles]` in `config.toml`.
## Testing
- `cargo test -p codex-config
profile_v2_rejects_legacy_profiles_in_base_user_config`
## Why
`--profile-v2 <name>` gives launchers and runtime entry points a named
profile config without making each profile duplicate the base user
config. The base `$CODEX_HOME/config.toml` still loads first, then
`$CODEX_HOME/<name>.config.toml` layers above it and becomes the active
writable user config for that session.
That keeps shared defaults, plugin/MCP setup, and managed/user
constraints in one place while letting a named profile override only the
pieces that need to differ.
## What Changed
- Added the shared `--profile-v2 <name>` runtime option with validated
plain names, now represented by `ProfileV2Name`.
- Extended config layer state so the base user config and selected
profile config are both `User` layers; APIs expose the active user layer
and merged effective user config.
- Threaded profile selection through runtime entry points: `codex`,
`codex exec`, `codex review`, `codex resume`, `codex fork`, and `codex
debug prompt-input`.
- Made user-facing config writes go to the selected profile file when
active, including TUI/settings persistence, app-server config writes,
and MCP/app tool approval persistence.
- Made plugin, marketplace, MCP, hooks, and config reload paths read
from the merged user config so base and profile layers both participate.
- Updated app-server config layer schemas to mark profile-backed user
layers.
## Limits
`--profile-v2` is still rejected for config-management subcommands such
as feature, MCP, and marketplace edits. Those paths remain tied to the
base `config.toml` until they have explicit profile-selection semantics.
Some adjacent background writes may still update base or global state
rather than the selected profile:
- marketplace auto-upgrade metadata
- automatic MCP dependency installs from skills
- remote plugin sync or uninstall config edits
- personality migration marker/default writes
## Verification
Added targeted coverage for profile name validation, layer
ordering/merging, selected-profile writes, app-server config writes,
session hot reload, plugin config merging, hooks/config fixture updates,
and MCP/app approval persistence.
---------
Co-authored-by: Codex <noreply@openai.com>
## Why
Codex intentionally ignores unknown `config.toml` fields by default so
older and newer config files keep working across versions. That leniency
also makes typo detection hard because misspelled or misplaced keys
disappear silently.
This change adds an opt-in strict config mode so users and tooling can
fail fast on unrecognized config fields without changing the default
permissive behavior.
This feature is possible because `serde_ignored` exposes the exact
signal Codex needs: it lets Codex run ordinary Serde deserialization
while recording fields Serde would otherwise ignore. That avoids
requiring `#[serde(deny_unknown_fields)]` across every config type and
keeps strict validation opt-in around the existing config model.
## What Changed
### Added strict config validation
- Added `serde_ignored`-based validation for `ConfigToml` in
`codex-rs/config/src/strict_config.rs`.
- Combined `serde_ignored` with `serde_path_to_error` so strict mode
preserves typed config error paths while also collecting fields Serde
would otherwise ignore.
- Added strict-mode validation for unknown `[features]` keys, including
keys that would otherwise be accepted by `FeaturesToml`'s flattened
boolean map.
- Kept typed config errors ahead of ignored-field reporting, so
malformed known fields are reported before unknown-field diagnostics.
- Added source-range diagnostics for top-level and nested unknown config
fields, including non-file managed preference source names.
### Kept parsing single-pass per source
- Reworked file and managed-config loading so strict validation reuses
the already parsed `TomlValue` for that source.
- For actual config files and managed config strings, the loader now
reads once, parses once, and validates that same parsed value instead of
deserializing multiple times.
- Validated `-c` / `--config` override layers with the same
base-directory context used for normal relative-path resolution, so
unknown override keys are still reported when another override contains
a relative path.
### Scoped `--strict-config` to config-heavy entry points
- Added support for `--strict-config` on the main config-loading entry
points where it is most useful:
- `codex`
- `codex resume`
- `codex fork`
- `codex exec`
- `codex review`
- `codex mcp-server`
- `codex app-server` when running the server itself
- the standalone `codex-app-server` binary
- the standalone `codex-exec` binary
- Commands outside that set now reject `--strict-config` early with
targeted errors instead of accepting it everywhere through shared CLI
plumbing.
- `codex app-server` subcommands such as `proxy`, `daemon`, and
`generate-*` are intentionally excluded from the first rollout.
- When app-server strict mode sees invalid config, app-server exits with
the config error instead of logging a warning and continuing with
defaults.
- Introduced a dedicated `ReviewCommand` wrapper in `codex-rs/cli`
instead of extending shared `ReviewArgs`, so `--strict-config` stays on
the outer config-loading command surface and does not become part of the
reusable review payload used by `codex exec review`.
### Coverage
- Added tests for top-level and nested unknown config fields, unknown
`[features]` keys, typed-error precedence, source-location reporting,
and non-file managed preference source names.
- Added CLI coverage showing invalid `--enable`, invalid `--disable`,
and unknown `-c` overrides still error when `--strict-config` is
present, including compound-looking feature names such as
`multi_agent_v2.subagent_usage_hint_text`.
- Added integration coverage showing both `codex app-server
--strict-config` and standalone `codex-app-server --strict-config` exit
with an error for unknown config fields instead of starting with
fallback defaults.
- Added coverage showing unsupported command surfaces reject
`--strict-config` with explicit errors.
## Example Usage
Run Codex with strict config validation enabled:
```shell
codex --strict-config
```
Strict config mode is also available on the supported config-heavy
subcommands:
```shell
codex --strict-config exec "explain this repository"
codex review --strict-config --uncommitted
codex mcp-server --strict-config
codex app-server --strict-config --listen off
codex-app-server --strict-config --listen off
```
For example, if `~/.codex/config.toml` contains a typo in a key name:
```toml
model = "gpt-5"
approval_polic = "on-request"
```
then `codex --strict-config` reports the misspelled key instead of
silently ignoring it. The path is shortened to `~` here for readability:
```text
$ codex --strict-config
Error loading config.toml:
~/.codex/config.toml:2:1: unknown configuration field `approval_polic`
|
2 | approval_polic = "on-request"
| ^^^^^^^^^^^^^^
```
Without `--strict-config`, Codex keeps the existing permissive behavior
and ignores the unknown key.
Strict config mode also validates ad-hoc `-c` / `--config` overrides:
```text
$ codex --strict-config -c foo=bar
Error: unknown configuration field `foo` in -c/--config override
$ codex --strict-config -c features.foo=true
Error: unknown configuration field `features.foo` in -c/--config override
```
Invalid feature toggles are rejected too, including values that look
like nested config paths:
```text
$ codex --strict-config --enable does_not_exist
Error: Unknown feature flag: does_not_exist
$ codex --strict-config --disable does_not_exist
Error: Unknown feature flag: does_not_exist
$ codex --strict-config --enable multi_agent_v2.subagent_usage_hint_text
Error: Unknown feature flag: multi_agent_v2.subagent_usage_hint_text
```
Unsupported commands reject the flag explicitly:
```text
$ codex --strict-config cloud list
Error: `--strict-config` is not supported for `codex cloud`
```
## Verification
The `codex-cli` `strict_config` tests cover invalid `--enable`, invalid
`--disable`, the compound `multi_agent_v2.subagent_usage_hint_text`
case, unknown `-c` overrides, app-server strict startup failure through
`codex app-server`, and rejection for unsupported commands such as
`codex cloud`, `codex mcp`, `codex remote-control`, and `codex
app-server proxy`.
The config and config-loader tests cover unknown top-level fields,
unknown nested fields, unknown `[features]` keys, source-location
reporting, non-file managed config sources, and `-c` validation for keys
such as `features.foo`.
The app-server test suite covers standalone `codex-app-server
--strict-config` startup failure for an unknown config field.
## Documentation
The Codex CLI docs on developers.openai.com/codex should mention
`--strict-config` as an opt-in validation mode for supported
config-heavy entry points once this ships.
# Why
Linked worktrees currently load their own project hook declarations, so
the same repo can present different hook definitions depending on which
checkout is active. https://github.com/openai/codex/pull/21762 tried to
share trust by giving matching worktree hooks a shared synthetic key,
but review pointed out that divergent worktree hook definitions would
then fight over one `trusted_hash`.
Instead of introducing a second trust model, this makes linked worktrees
use the root checkout as the single source of truth for project hook
declarations. Worktree-local project config can still diverge for
unrelated settings, but project hooks now keep one real source path and
one trust state per repo.
# What
- Teach project config loading to remember the matching root-checkout
`.codex/` folder for actual linked-worktree project layers.
- Keep ordinary project config sourced from the worktree, but replace
project hook declarations with the root checkout's matching layer before
hook discovery runs, including linked-worktree layers with `.codex/` but
no local `config.toml`.
- Make hook discovery use that authoritative hook folder for both
`hooks.json` and TOML hook source paths, so linked worktrees produce the
same hook key and trust state as the root checkout.
- Cover the linked-worktree path plus regressions for missing worktree
`config.toml` and nested non-worktree project roots.
Add Codex config for static trace span attributes and structured W3C
tracestate field upserts. The config flows through OtelSettings so
callers can attach trace metadata without touching every span call site.
Apply span attributes with an SDK span processor so every exported
trace span carries the configured metadata. Model tracestate as nested
member fields so configured keys can be upserted while unrelated
propagated state in the same member is preserved.
Validate configured tracestate before installing provider-global state,
including header-unsafe values the SDK does not reject by itself. This
keeps Codex from propagating malformed trace context from config.
Update the config schema, public docs, and OTLP loopback coverage for
config parsing, span export, propagation, and invalid-header rejection.
## Description
Ignore these top-level config keys when loading project-scoped
config.toml files:
```
"openai_base_url",
"chatgpt_base_url",
"model_provider",
"model_providers",
"profile",
"profiles",
"experimental_realtime_ws_base_url",
```
## What changed
- Add a project-local config denylist for credential-routing fields such
as `openai_base_url`, `chatgpt_base_url`, `model_provider`,
`model_providers`, `profile`, `profiles`, and
`experimental_realtime_ws_base_url`.
- Strip those fields from project config layers before they participate
in effective config merging, while leaving safe project-local settings
intact.
- Track ignored project-local keys on config layers and surface a
startup warning telling users to move those settings to user-level
`config.toml` if they intentionally need them.
- Update profile behavior coverage so project-local `profile` /
`profiles` entries are ignored instead of overriding user-level profile
selection.
## Verification
- `cargo test -p codex-config`
- `cargo test -p codex-core
project_layer_ignores_unsupported_config_keys`
- `cargo test -p codex-core project_profiles_are_ignored`
- `cargo test -p codex-core config::config_loader_tests`
## Why
The explicit profile path from #20117 is meant for standalone testing,
but it still inherited the
shell cwd and all managed requirements implicitly. The pre-existing
launcher path even called out
that it did not support a separate cwd yet in
[`debug_sandbox.rs`](https://github.com/openai/codex/blob/509453f688a30929432be866402d1ea46aa12169/codex-rs/cli/src/debug_sandbox.rs#L174-L179).
For a standalone command, the useful default is to let the caller choose
the project directory being
tested and to avoid administrator-provided constraints unless the caller
explicitly wants to test
those too.
## What changed
- Add explicit-profile-only `-C/--cd DIR`, and use that cwd for both
profile resolution and command
execution.
- Add explicit-profile-only `--include-managed-config`.
- Make explicit profile mode skip managed requirement sources by
default, including cloud
requirements, MDM requirements, `/etc/codex/requirements.toml`, and the
legacy managed-config
requirements projection.
- Preserve all existing invocations outside the explicit-profile path.
## Stack
1. #20117 `sandbox-ui-profile`
2. #20118 `sandbox-ui-config` --> this PR
Both PRs are additive. Replay JSON is intentionally deferred to a
follow-up design pass.
## Tests ran
- `cargo test -p codex-cli debug_sandbox`
- `cargo test -p codex-cli sandbox_macos_`
- `cargo test -p codex-core
load_config_layers_can_ignore_managed_requirements`
- `cargo test -p codex-core
load_config_layers_includes_cloud_requirements`
- macOS branch-binary smoke on the rebased top of stack: `-C` changed
execution cwd, explicit
profile mode omitted managed proxy env under `env -i`, and
`--include-managed-config` restored it.
- Linux devbox branch-binary smoke on the rebased top of stack: `-C`
changed execution cwd for
built-in and user-defined explicit profiles.
## Summary
- Extracted the shared filesystem types and `ExecutorFileSystem` trait
into a new `codex-file-system` crate
- Switched `codex-config` and `codex-git-utils` to depend on that crate
instead of `codex-exec-server`
- Kept `codex-exec-server` re-exporting the same API for existing
callers
## Testing
- Ran `cargo test -p codex-file-system`
- Ran `cargo test -p codex-git-utils`
- Ran `cargo test -p codex-config`
- Ran `cargo test -p codex-exec-server`
- Ran `just fix -p codex-file-system`, `just fix -p codex-git-utils`,
`just fix -p codex-config`, `just fix -p codex-exec-server`
- Ran `just fmt`
- Updated and verified the Bazel module lockfile
# Why
Requirements support host-specific
`remote_sandbox_config.hostname_patterns`, but config loading previously
resolved and passed the system hostname through every config-loading
path even when no requirements layer used `remote_sandbox_config`. On
machines where hostname lookup is slow, startup and app-server config
reads paid for a feature that was not active.
We only need the hostname when a requirements layer actually declares
`remote_sandbox_config`, so this moves hostname resolution to the single
requirements merge point and keeps all other config callers unaware of
hostname matching.
# What
- Removed the eager `host_name` plumbing from
`load_config_layers_state`, `load_requirements_toml`, `ConfigBuilder`,
app-server `ConfigManager`, network proxy loading, and related call
sites.
- Resolve the hostname inside
`merge_requirements_with_remote_sandbox_config` only when the incoming
requirements contain `remote_sandbox_config`.
## Why
Config loading had become split across crates: `codex-config` owned the
config types and merge logic, while `codex-core` still owned the loader
that assembled the layer stack. This change consolidates that
responsibility in `codex-config`, so the crate that defines config
behavior also owns how configs are discovered and loaded.
To make that move possible without reintroducing the old dependency
cycle, the shell-environment policy types and helpers that
`codex-exec-server` needs now live in `codex-protocol` instead of
flowing through `codex-config`.
This also makes the migrated loader tests more deterministic on machines
that already have managed or system Codex config installed by letting
tests override the system config and requirements paths instead of
reading the host's `/etc/codex`.
## What Changed
- moved the config loader implementation from `codex-core` into
`codex-config::loader` and deleted the old `core::config_loader` module
instead of leaving a compatibility shim
- moved shell-environment policy types and helpers into
`codex-protocol`, then updated `codex-exec-server` and other downstream
crates to import them from their new home
- updated downstream callers to use loader/config APIs from
`codex-config`
- added test-only loader overrides for system config and requirements
paths so loader-focused tests do not depend on host-managed config state
- cleaned up now-unused dependency entries and platform-specific cfgs
that were surfaced by post-push CI
## Testing
- `cargo test -p codex-config`
- `cargo test -p codex-core config_loader_tests::`
- `cargo test -p codex-protocol -p codex-exec-server -p
codex-cloud-requirements -p codex-rmcp-client --lib`
- `cargo test --lib -p codex-app-server-client -p codex-exec`
- `cargo test --no-run --lib -p codex-app-server`
- `cargo test -p codex-linux-sandbox --lib`
- `cargo shear`
- `just bazel-lock-check`
## Notes
- I did not chase unrelated full-suite failures outside the migrated
loader surface.
- `cargo test -p codex-core --lib` still hits unrelated proxy-sensitive
failures on this machine, and Windows CI still shows unrelated
long-running/timeouting test noise outside the loader migration itself.