## Summary

Adds Admin API support for reading and updating project service tier
settings.

## Changes

- Retrieve a project’s default and enabled service tiers.
- Update either setting independently, including an empty list of
enabled optional tiers.

Co-authored-by: dpiet-oai <[email protected]>

## Summary

Adds typed 12-hour Responses prompt-cache lifetimes and optional
cache-write usage details.

## Changes

- Accept "12h" alongside "30m" in Responses request and response TTL
types.
- Expose optional cache-write details with separate 30-minute and
12-hour token counts.

## Compatibility

Callers that type a returned TTL as exactly `Literal["30m"]` should
allow `"12h"` too. The optional usage breakdown now decodes as a typed
model.

Co-authored-by: marcuswood-oai <[email protected]>

Consolidate generated-file ownership guidance in the contributor guide
and link to it from `AGENTS.md`. Explain how to trace a fix to the API
schema, SDK generator, or a handwritten file, with a repository-specific
example.

Verified the documentation links and section anchors and ran `git diff
--check`.

Automated Release PR
---


##
[3.45.0](v3.44.0...v3.45.0)
(2026-11-03)


### Features

* **api:** add 12-hour Responses caching and cache-write usage
([#4240](#4240))
([5f717b5](5f717b5))
* **api:** add project service tier settings
([#4239](#4239))
([1a2a3d0](1a2a3d0))


### Documentation

* clarify generated-file ownership
([#4241](#4241))
([0309a8c](0309a8c))

---
This PR was generated with [Release
Please](https://github.com/googleapis/release-please). See
[documentation](https://github.com/googleapis/release-please#release-please).

Co-authored-by: openai-sdks[bot] <284451331+openai-sdks[bot]@users.noreply.github.com>