## Why
Permission profile allowlists are an enterprise security boundary, but
they also need to compose across the managed requirements layers added
in #24620.
A map representation lets each requirements layer add, allow, or revoke
individual profiles without replacing an entire array.
## Managed Contract
Administrators configure the mergeable allow map with
`allowed_permission_profiles`. A recommended enterprise configuration
explicitly lists every built-in and custom profile users should be able
to select:
```toml
default_permissions = "review_only"
[allowed_permission_profiles]
":read-only" = true
":workspace" = true
review_only = true
# ":danger-full-access" is intentionally omitted, so it is denied.
[permissions.review_only]
extends = ":read-only"
```
- Profiles whose effective merged value is `true` are allowed.
- Missing profiles and profiles set to `false` are denied.
- This is a closed allowlist: built-in profiles and profiles introduced
in future versions are denied unless explicitly allowed.
- Explicitly list each built-in profile the enterprise wants to make
available. Omit built-ins such as `:danger-full-access` when they should
remain unavailable.
- Set `default_permissions` explicitly to the allowed profile users
should receive when they have no local selection.
- Higher-precedence layers override only the profile keys they define.
- `false` is only needed when a higher-precedence layer must revoke a
`true` inherited from a lower layer.
- Explicit keys must refer to known built-in or managed profiles.
A custom or narrowed allowlist requires an allowed
`default_permissions`. For compatibility, if both `:workspace` and
`:read-only` are explicitly allowed, an omitted default resolves to
`:workspace`; customer configurations should still set the intended
default explicitly.
When `allowed_permission_profiles` is absent, existing implicit
permission and legacy `sandbox_mode` behavior is unchanged.
## What Changed
- Add `allowed_permission_profiles` as a `BTreeMap<String, bool>` that
merges per profile across requirements layers.
- Enforce managed defaults, strict denial of omitted profiles, and the
explicitly allowed standard-pair fallback.
- Expose `allowedPermissionProfiles` through `configRequirements/read`
and regenerate its schemas.
- Add regression coverage for map composition and revocation, managed
defaults, strict denial of omitted built-ins, and API output.
## Verification
- Focused `codex-config` coverage for layered map composition and
revocation
- Focused `codex-core` coverage for managed defaults, invalid defaults,
strict denial of omitted built-ins, and the standard built-in pair
- Focused `codex-app-server` coverage for requirements API output
- Scoped Clippy for `codex-config`, `codex-core`,
`codex-app-server-protocol`, and `codex-app-server`
## Documentation
The managed `requirements.toml` documentation should introduce
`allowed_permission_profiles` as a closed permission-profile allowlist
before this setting is published on developers.openai.com.
---------
Co-authored-by: Codex <noreply@openai.com>
## Summary
PR 2 of 5 in the cloud-managed config client stack.
Adds a shared requirements-layer composition engine. The composer
defines how ordered requirements layers combine, with focused tests for
the merge semantics and provenance behavior. The final PR in the stack
wires runtime requirements sources into this path.
## Details
- Mental model: requirements layers are ordered lowest priority first,
matching `ConfigLayerStack`; lower-priority layers provide defaults
while higher-priority layers win scalar/list conflicts.
- Regular fields use config-style TOML merging, including recursive
table merging, so requirements layering follows the same broad model as
`config.toml` layering.
- Domain-specific fields keep explicit semantics: `rules.prefix_rules`
and hooks preserve high-priority-first output, hooks fail closed on
active managed-dir conflicts, and `permissions.filesystem.deny_read`
dedupes as a stable high-priority-first union.
- `remote_sandbox_config` is evaluated within each layer before the
regular TOML merge, so host-specific sandbox constraints do not leak
across layers.
- Provenance points at the exact source when one layer owns a value and
uses composite provenance when a table field is assembled from multiple
layers.
## Validation
Local validation:
- `just fmt`
- `cargo check -p codex-config`
- `just test -p codex-config requirements_composition`
- `git diff --check`
CI will run the broader test matrix.
