feat: api: support per-acquire start_url override on browser pool acquire

Author: stainless-app[bot]

.stats.yml

@@ -1,4 +1,4 @@
 configured_endpoints: 122
-openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/kernel/kernel-7cde13c82c71b7a5fd64b592f853a7c999c0e0c02dce161e6126d0e99df3412b.yml
-openapi_spec_hash: 52cda226c70a248cbea3af6c52822b44
+openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/kernel/kernel-d9b82fc5346c9be1bf9c2b18792fdcdec6a80a86153ca765c9e93e597b46fa24.yml
+openapi_spec_hash: 9cbaab975acfa421b795d11aa635c57e
 config_hash: 99b2b2a25e8067ad9c9214e38e01d64c

browserpool.go

@@ -545,6 +545,10 @@ type BrowserPoolAcquireParams struct {
 	// project. Applies to this lease only and is cleared when the browser is released
 	// back to the pool.
 	Name param.Opt[string] `json:"name,omitzero"`
+	// Optional URL to navigate the acquired browser to. Overrides the pool's start_url
+	// for this acquire only. Best-effort: failures to navigate do not fail the
+	// acquire.
+	StartURL param.Opt[string] `json:"start_url,omitzero"`
 	// Optional user-defined key-value tags for the acquired browser session, used to
 	// find and group sessions later. Applies to this lease only and are cleared when
 	// the browser is released back to the pool. Up to 50 pairs.

browserpool_test.go

@@ -217,6 +217,7 @@ func TestBrowserPoolAcquireWithOptionalParams(t *testing.T) {
 		kernel.BrowserPoolAcquireParams{
 			AcquireTimeoutSeconds: kernel.Int(0),
 			Name:                  kernel.String("checkout-flow-1"),
+			StartURL:              kernel.String("https://example.com"),
 			Tags: kernel.Tags{
 				"team": "backend",
 				"env":  "staging",