## Problem
Users without Codex access can hit a confusing local login loop. In the
denial case, the callback could fall through to generic behavior
(including a plain "Missing authorization code" page) instead of clearly
explaining that access was denied.
<img width="842" height="464" alt="Screenshot 2026-02-19 at 11 43 45 PM"
src="https://github.com/user-attachments/assets/f7a25e1d-e480-4ac2-b0ff-8bfe31003e66"
/>
<img width="842" height="464" alt="Screenshot 2026-02-19 at 11 44 53 PM"
src="https://github.com/user-attachments/assets/8a4fe6e4-b27b-483c-9f0c-60164933221d"
/>
## Scope
This PR improves local login error clarity only. It does not change
entitlement policy, RBAC rules, or who is allowed to use Codex.
## What Changed
- The local OAuth callback handler now parses `error` and
`error_description` on `/auth/callback` and exits the callback loop with
a real failure.
- Callback failures render a branded local Codex error page instead of a
generic/plain page.
- `access_denied` + `missing_codex_entitlement` is now mapped to an
explicit user-facing message telling the user Codex is not enabled for
their workspace and to contact their workspace administrator for access.
- Unknown OAuth callback errors continue to use a generic error page
while preserving the OAuth error code/details for debugging.
- Added the login error page template to Bazel assets so the local
binary can render it in Bazel builds.
## Non-goals
- No TUI onboarding/toast changes in this PR.
- No backend entitlement or policy changes.
## Tests
- Added an end-to-end `codex-login` test for `access_denied` +
`missing_codex_entitlement` and verified the page shows the actionable
admin guidance.
- Added an end-to-end `codex-login` test for a generic `access_denied`
reason to verify we keep a generic fallback page/message.
This PR configures Codex CLI so it can be built with
[Bazel](https://bazel.build) in addition to Cargo. The `.bazelrc`
includes configuration so that remote builds can be done using
[BuildBuddy](https://www.buildbuddy.io).
If you are familiar with Bazel, things should work as you expect, e.g.,
run `bazel test //... --keep-going` to run all the tests in the repo,
but we have also added some new aliases in the `justfile` for
convenience:
- `just bazel-test` to run tests locally
- `just bazel-remote-test` to run tests remotely (currently, the remote
build is for x86_64 Linux regardless of your host platform). Note we are
currently seeing the following test failures in the remote build, so we
still need to figure out what is happening here:
```
failures:
suite::compact::manual_compact_twice_preserves_latest_user_messages
suite::compact_resume_fork::compact_resume_after_second_compaction_preserves_history
suite::compact_resume_fork::compact_resume_and_fork_preserve_model_history_view
```
- `just build-for-release` to build release binaries for all
platforms/architectures remotely
To setup remote execution:
- [Create a buildbuddy account](https://app.buildbuddy.io/) (OpenAI
employees should also request org access at
https://openai.buildbuddy.io/join/ with their `@openai.com` email
address.)
- [Copy your API key](https://app.buildbuddy.io/docs/setup/) to
`~/.bazelrc` (add the line `build
--remote_header=x-buildbuddy-api-key=YOUR_KEY`)
- Use `--config=remote` in your `bazel` invocations (or add `common
--config=remote` to your `~/.bazelrc`, or use the `just` commands)
## CI
In terms of CI, this PR introduces `.github/workflows/bazel.yml`, which
uses Bazel to run the tests _locally_ on Mac and Linux GitHub runners
(we are working on supporting Windows, but that is not ready yet). Note
that the failures we are seeing in `just bazel-remote-test` do not occur
on these GitHub CI jobs, so everything in `.github/workflows/bazel.yml`
is green right now.
The `bazel.yml` uses extra config in `.github/workflows/ci.bazelrc` so
that macOS CI jobs build _remotely_ on Linux hosts (using the
`docker://docker.io/mbolin491/codex-bazel` Docker image declared in the
root `BUILD.bazel`) using cross-compilation to build the macOS
artifacts. Then these artifacts are downloaded locally to GitHub's macOS
runner so the tests can be executed natively. This is the relevant
config that enables this:
```
common:macos --config=remote
common:macos --strategy=remote
common:macos --strategy=TestRunner=darwin-sandbox,local
```
Because of the remote caching benefits we get from BuildBuddy, these new
CI jobs can be extremely fast! For example, consider these two jobs that
ran all the tests on Linux x86_64:
- Bazel 1m37s
https://github.com/openai/codex/actions/runs/20861063212/job/59940545209?pr=8875
- Cargo 9m20s
https://github.com/openai/codex/actions/runs/20861063192/job/59940559592?pr=8875
For now, we will continue to run both the Bazel and Cargo jobs for PRs,
but once we add support for Windows and running Clippy, we should be
able to cutover to using Bazel exclusively for PRs, which should still
speed things up considerably. We will probably continue to run the Cargo
jobs post-merge for commits that land on `main` as a sanity check.
Release builds will also continue to be done by Cargo for now.
Earlier attempt at this PR: https://github.com/openai/codex/pull/8832
Earlier attempt to add support for Buck2, now abandoned:
https://github.com/openai/codex/pull/8504
---------
Co-authored-by: David Zbarsky <dzbarsky@gmail.com>
Co-authored-by: Michael Bolin <mbolin@openai.com>
daniel-oaiandGitHub
