release: 3.20.0 (#3957)

Automated Release PR
---


##
[3.20.0](https://github.com/openai/openai-python/compare/v3.19.2...v3.20.0)
(2026-09-28)


### Features

* **api:** add Agents credential and session options
([#3967](https://github.com/openai/openai-python/issues/3967))
([bb68198](https://github.com/openai/openai-python/commit/bb68198a4bb4a161cbb32a28c3888a51540eaf0f))
* **api:** add Cyber access programs to Responses
([#3956](https://github.com/openai/openai-python/issues/3956))
([09c5b6f](https://github.com/openai/openai-python/commit/09c5b6f13f716ad4e417fd7ba9209a8a057e0383))
* **responses:** opt in to incremental WebSocket text and tool snapshots
([#3973](https://github.com/openai/openai-python/issues/3973))
([d0207b4](https://github.com/openai/openai-python/commit/d0207b48c043741ff483d7a8c945f8003d1ee714))
* **responses:** preserve detailed WebSocket accumulator snapshots
([#3981](https://github.com/openai/openai-python/issues/3981))
([a380cf2](https://github.com/openai/openai-python/commit/a380cf256abc2aa51cbf5d49437ae039b9aa9b12))


### Bug Fixes

* **client:** retry unmapped TLS transport errors
([#3982](https://github.com/openai/openai-python/issues/3982))
([0d35a26](https://github.com/openai/openai-python/commit/0d35a2640458b64ed2ff4a7c9b1f1a1e5705336e))
* **live:** avoid hangs at fractional transcript grouping deadlines
([#3970](https://github.com/openai/openai-python/issues/3970))
([4ef4129](https://github.com/openai/openai-python/commit/4ef4129e85e81a285905755e57b392aa9e77f9bd))
* **live:** keep query parameters out of WebSocket endpoint paths
([#3972](https://github.com/openai/openai-python/issues/3972))
([f9c458b](https://github.com/openai/openai-python/commit/f9c458b759e3756979fceebf50bffa78d9cf0b97))
* **live:** preserve caller queues and prevent uncertain WebSocket
replay ([#3980](https://github.com/openai/openai-python/issues/3980))
([80e9686](https://github.com/openai/openai-python/commit/80e96860b5ccbfcf4a1c9dd9947fc31cd021037a))
* **realtime:** preserve base URL queries in WebSocket upgrades
([#3971](https://github.com/openai/openai-python/issues/3971))
([f7bd4a7](https://github.com/openai/openai-python/commit/f7bd4a703cad904e4f5d91ec9d7abac70d8c0bd6))
* **realtime:** retain configured queues without replaying attempted
sends ([#3978](https://github.com/openai/openai-python/issues/3978))
([a52805c](https://github.com/openai/openai-python/commit/a52805c2537422ad602eba2bf66072880ea3fd22))


### Chores

* **api:** clarify documented API error responses
([#3965](https://github.com/openai/openai-python/issues/3965))
([384fee3](https://github.com/openai/openai-python/commit/384fee3252e2336a85450ff38f9bae41f9199616))
* **api:** document batch error responses
([#3961](https://github.com/openai/openai-python/issues/3961))
([6e4a79c](https://github.com/openai/openai-python/commit/6e4a79cc8c7e640e7ac4be710db32fe20b1020f2))
* **api:** document files and uploads error responses
([#3960](https://github.com/openai/openai-python/issues/3960))
([a9d727f](https://github.com/openai/openai-python/commit/a9d727ff9c4a38fc5dca8d31bd3dd76f473cfc27))
* **api:** document fine-tuning and model errors
([#3964](https://github.com/openai/openai-python/issues/3964))
([5d4003c](https://github.com/openai/openai-python/commit/5d4003c12d5df5a5faed35971cac3bcb711fdf7d))
* **api:** document Responses not-found errors
([#3959](https://github.com/openai/openai-python/issues/3959))
([63099e7](https://github.com/openai/openai-python/commit/63099e739d25cb18f90cae93648471bf037bc46f))
* **api:** document stored chat completion errors
([#3963](https://github.com/openai/openai-python/issues/3963))
([a73fe0c](https://github.com/openai/openai-python/commit/a73fe0c3d404335a342d1251bd32709b8e3d76f2))

---
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