[betegon]

Consumers that inspect a raw request before sending it currently have to repeat URL, header and body preparation. Expose sentry.client.prepareRequest(options): Promise<Request> from the concrete client, and extract the same preparation stage used by ordinary SDK requests. This lets consumers inspect and dispatch one native request through their existing transport.

Before / after

Before, the CLI prepares URLs and effective headers for pagination identity and previews, then rebuilds them during raw dispatch. The SDK cannot expose its prepared request without sending it. Passing query alongside a URL that already has query parameters also appends a second ?.

After:

const sentry = createSentryClient({ baseUrl: "https://example.test/sentry" });
const request = await sentry.client.prepareRequest({
  method: "GET",
  url: "/api/0/organizations/example/events/?field=id&field=title&cursor=old",
  query: { cursor: "opaque-next", per_page: 50 },
});
// No fetch yet. Both field values remain and the old cursor is replaced:
// https://example.test/sentry/api/0/organizations/example/events/?field=id&field=title&cursor=opaque-next&per_page=50
const response = await fetch(request);
// The consumer retains raw status, headers and body handling.

Preparation runs configured auth, validation, serialization and request interceptors once. It preserves the native signal and does not invoke fetch or response/error processing. Transports can still attach browser CSRF, credentials or routing when dispatching. Existing custom Client implementations accepted by generated operations need no new method.

The shared URL builder replaces explicitly serialized query keys while retaining unrelated repeated values and encoding. With the default serializer, null clears a parameter and undefined leaves it unchanged. Custom serializers and opaque cursor strings remain supported. Ordinary requests use the same behavior.

Validation and scope

Build, typecheck, 253 SDK tests and 2 Node cancellation tests pass. Coverage compares preparation with ordinary dispatch, exercises raw and browser transports, custom cursors/serializers, body handling, cancellation, concurrent clients and reconfiguration. The packed npm artifact is exercised in a clean Node consumer, including public types and raw non-2xx responses. Review and cleanup completed.

Refs #93 and #99. This is the generic preparation slice for Toolkit #1659; CLI adoption follows publication. Request identity, navigation history, bookmark codecs, output and endpoint recovery remain consumer policy. No production or browser-login validation is claimed, and the remaining v1 adoption gates stay open.