API Surface Review (Polar)

The handle is the diff. The evidence is what this change does to the API contract, and whether any of it is breaking.

This is where Polar's most expensive review mistakes live. A schema change does not stay in the repo: it flows into docs/openapi.json, the generated TypeScript client, the Speakeasy SDKs under sdk/, and out to merchants who already wrote code against it.

Scope

Diffs touching **/schemas.py, **/endpoints.py, polar/openapi.py, docs/openapi.json, sdk/, clients/packages/client/.

CI already does part of this job. The OpenAPI Diff workflow posts the schema delta as a PR comment, and OpenAPI Client Regeneration Check fails if the client is stale. Do not recompute either by hand. Read the diff comment if it exists and judge whether the delta is acceptable; that judgement is the thing CI cannot make.