Legacy strict schema, current payload:

HTTP/1.1 400 Bad Request
content-type: application/json

{"ok":false,"error":{"code":"invalid_input","message":"rpc input validation failed","issues":[{"message":"Unrecognized key: \"experimental_hostId\"","path":["source"]}]}}

Current schema, same payload:

HTTP/1.1 200 OK
content-type: application/json

{"ok":true,"result":{"kind":"text","content":"{\n  \"name\": \"issue-2519-repro\",\n  \"version\": \"1.0.0\"\n}\n","sha256":"955e50d1db03f9f36007472138b7fdb4230318c23a4ec7a711a5c9bc404b4fa7","absolutePath":"/tmp/bb-report-2519-project/package.json","relativePath":"package.json"}}