## Why
Bazel remote configuration was selected in several CI scripts and
workflow steps. That made the BuildBuddy tenant policy easy to duplicate
and harder to audit, especially for fork pull requests that must not use
the OpenAI tenant.
This builds on
[sluongng/buildbuddy-ci-host-routing](https://github.com/openai/codex/compare/main...sluongng:codex:sluongng/buildbuddy-ci-host-routing)
and consolidates the policy in one place.
## What to do if this breaks you
See `codex-rs/docs/bazel.md` for details. TLDR:
1. make a BuildBuddy API key and put it in `~/.bazelrc`
2. if you're an OpenAI employee, add `common
--config=buildbuddy-openai-rbe` to `user.bazelrc` in the repo root
Run `just bazel-test` to ensure it works.
Note that `just bazel-remote-test` no longer exists, you need to select
a remote configuration as documented to use RBE.
## What changed
- Add `.github/scripts/run_bazel_with_buildbuddy.py` as the shared Bazel
wrapper and Python library. It selects the OpenAI host only for trusted
upstream GitHub Actions runs, routes keyed fork runs to the generic
host, and falls back to local Bazel execution when no key is available.
- Move endpoint selection into explicit `.bazelrc` configurations and
update Bazel CI, query helpers, and `rusty_v8` staging to use the shared
policy. Loading-phase target-discovery queries remain local.
- Add wrapper and `rusty_v8` unit coverage, plus `just test-scripts` for
the `.github/scripts` Python tests.
- Document local Bazel usage, `user.bazelrc` setup, BuildBuddy
configurations, and CI behavior in `codex-rs/docs/bazel.md`.
## Validation
- `just test-scripts`
- `bash -n .github/scripts/run-bazel-ci.sh
.github/scripts/run-bazel-query-ci.sh
.github/scripts/run-argument-comment-lint-bazel.sh
scripts/list-bazel-clippy-targets.sh`
- `python3 -m py_compile .github/scripts/run_bazel_with_buildbuddy.py
.github/scripts/test_run_bazel_with_buildbuddy.py
.github/scripts/test_rusty_v8_bazel.py
.github/scripts/rusty_v8_bazel.py`
- `ruff check .github/scripts/run_bazel_with_buildbuddy.py
.github/scripts/test_run_bazel_with_buildbuddy.py
.github/scripts/test_rusty_v8_bazel.py
.github/scripts/rusty_v8_bazel.py`
## Summary
- skip startup websocket prewarm setup when the model client has
Responses-over-WebSocket disabled
- avoid making HTTP-only sessions build prewarm prompt/tool state that
cannot produce a reusable websocket session
## Why
Recent macOS timing flakes were timing out while waiting for first-turn
events in HTTP-only core tests. Startup prewarm is only useful for
websocket-capable providers, but it was scheduled for every session. For
HTTP-only test providers this added unnecessary async startup work
before the regular turn could reach the mocked response flow.
## Testing
- bazel test //codex-rs/core:core-all-test
--test_filter=suite::auto_review::remote_model_override_uses_catalog_model_for_strict_auto_review
--test_output=errors
- bazel test //codex-rs/core:core-all-test
--test_filter=suite::request_permissions_tool::approved_folder_write_request_permissions_unblocks_later_apply_patch
--test_output=errors
## Why
`Runtime::block_on` executes the top-level future on the caller's OS
thread, not on one of Tokio's worker threads. That matters for the
interactive CLI because the Tokio runtime already configures larger
worker stacks, while the process main thread can still have a smaller
platform default stack.
This showed up as a `/clear` crash on macOS: starting a fresh TUI thread
reloads config, and the stack-heavy TOML deserialization path can
overflow before the new session is actually started.
## What Changed
- Run the regular `arg0_dispatch_or_else` async entrypoint on a named
`codex-main` thread.
- Give that thread the same `TOKIO_WORKER_STACK_SIZE_BYTES` stack budget
already used for Tokio worker threads.
- Keep `Arg0DispatchPaths` and the arg0 alias guard lifetime behavior
the same.
- Resume panics from the spawned main thread so panic behavior is
preserved.
## Verification
- `cargo check -p codex-cli` currently fails because the top-level
CLI/TUI future is not `Send` under the new thread boundary.
## Summary
Keep the full `TestCodex` harness alive in plugin integration tests
instead of returning only the `CodexThread`.
## Why
The helper was moving a temporary `codex_home` into `TestCodex`, then
immediately dropping the harness and returning only the thread. For
plugin MCP tests, the MCP server cwd is inside that temporary home. If
the temp directory is removed while MCP startup is still racing, the
server launch can fail with `No such file or directory`.
Keeping the harness in scope keeps the temp home alive for the test
duration and removes the lifetime race behind the recent
`explicit_plugin_mentions_inject_plugin_guidance` flake.
## Validation
- `just fmt`
- `just test -p codex-core
explicit_plugin_mentions_inject_plugin_guidance`
## Why
`/clear` starts a fresh thread with `InitialHistory::Cleared`, which
re-enters the thread/session startup path. That path now builds large
async futures through `ThreadManagerState::spawn_thread_with_source`,
`Codex::spawn`, and `Session::new`. Separately, TUI config rebuilds for
cwd and permission-profile changes build a similarly heavy
`ConfigBuilder::build()` future inside the app task. In debug and Bazel
runs, those call chains can put enough state on the caller stack to
abort before startup or config refresh completes.
This change keeps the behavior the same while moving the heaviest future
frames off the caller stack.
## What changed
- Box `Codex::spawn(...)` in `codex-rs/core/src/thread_manager.rs`
before awaiting it from `spawn_thread_with_source`.
- Box `Session::new(...)` in `codex-rs/core/src/session/mod.rs` before
awaiting it from `Codex::spawn_internal`.
- Route `ConfigBuilder::build()` through a small `tokio::spawn` helper
in `codex-rs/tui/src/app/config_persistence.rs` so cwd and
permission-profile config rebuilds run on a runtime worker stack while
preserving error context.
## Verification
CI is running on the PR.
No new targeted tests were added. This is a mechanical stack-pressure
reduction that keeps the existing behavior and error propagation intact.
Stack split from #25708. Original PR intentionally left open. This fifth
PR adds coverage that a remotely selected multi-agent runtime is applied
when the model is selected before the first turn.
Stack split from #25708. Original PR intentionally left open. This
fourth PR adds coverage that remote model multi-agent runtime selectors
override local feature flag defaults.
Cooper Gamble