release: 0.57.0

[stainless-app]

Automated Release PR

0.57.0 (2026-05-22)

Full Changelog: v0.56.0...v0.57.0

Features

• [kernel-1116] browser events api integration (bfd4043)
• api: type can_reauth_reason as an enum on ManagedAuth (c9a6c75)
• browsers: accept chrome_policy on POST /browsers (KERNEL-1216) (b1807a2)
• EOL persistent browsers: openapi limits (253be85)

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Note

Medium Risk
Medium risk due to new SSE streaming surface area and multiple breaking API removals/shape changes (deprecated persistent browser delete/persistence fields, project limit fields). Main logic is generated client code, but it changes request/response schemas and public SDK methods.

Overview
Bumps the SDK to 0.57.0 and updates the generated client to match a new OpenAPI spec.

Adds a new browsers.telemetry.stream() SSE endpoint (sync/async, raw/streaming variants) plus a large set of typed browser telemetry event models, and wires telemetry configuration into POST /browsers and PATCH /browsers/{id}.

Extends browser session APIs to accept/return chrome_policy overrides, updates docs/examples accordingly, and removes end-of-life persistent browser support (drops persistence fields, DELETE /browsers by persistent_id, and max_persistent_sessions project limit overrides) while refining some endpoint docstrings (e.g., browser pool start_url, proxy checks).

^{Reviewed by Cursor Bugbot for commit e81bfa4. Bugbot is set up for automated code reviews on this repo. Configure here.}

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[stainless-app]

🧪 Testing

To try out this version of the SDK:

pip install 'https://pkg.stainless.com/s/kernel-python/253be85c497bf65329c484e28a3732b3bd5b3208/kernel-0.56.0-py3-none-any.whl'

Expires at: Sun, 21 Jun 2026 16:49:25 GMT
Updated at: Fri, 22 May 2026 16:49:25 GMT

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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^{Reviewed by Cursor Bugbot for commit f0b2dc9. Configure here.}

[cursor]

Omit sentinel not stripped by strip_not_given for header

High Severity

The last_event_id parameter defaults to omit (an Omit instance), but strip_not_given only removes values that are isinstance(value, NotGiven). Since Omit and NotGiven are unrelated classes, strip_not_given({"Last-Event-ID": omit}) keeps the key with the Omit sentinel object as its value instead of removing it. This causes a garbage Last-Event-ID header (the repr of the Omit object) to be sent on every telemetry stream request where the user doesn't explicitly provide last_event_id.

Additional Locations (1)

• src/kernel/resources/browsers/telemetry.py#L149-L150

 

^{Reviewed by Cursor Bugbot for commit f0b2dc9. Configure here.}

[IlyaasK]

I checked this on the PR branch and I believe this is a false positive.

strip_not_given({"Last-Event-ID": last_event_id}) does not remove omit, since strip_not_given only strips NotGiven. But request headers are later passed through _build_headers(...), which calls _merge_mappings(...) in src/kernel/_base_client.py. _merge_mappings(...) explicitly removes values that are instances of Omit before httpx.Headers is constructed.

I verified with httpx.MockTransport on this branch:

• default sync client.browsers.telemetry.stream("browser_123") does not send Last-Event-ID
• default async stream also does not send Last-Event-ID
• last_event_id="42" correctly sends Last-Event-ID: 42

So the Omit sentinel does not leak onto the wire.

[IlyaasK]

review test

[IlyaasK]

lgtm

[stainless-app]

🤖 Release is at https://github.com/kernel/kernel-python-sdk/releases/tag/v0.57.0 🌻