An inference request and each attempt at an engine carry gen_ai.*: the
operation, the requested and answering model, max_tokens, temperature and
top_p when the client set them, the session as the conversation id, the
input, output and cached tokens, and on an attempt the engine that answered.
A customer's Grafana, Jaeger or Langfuse then shows llmgw's calls as model
calls. No prompt or answer text is ever put in a span, and a test says so.
BACKLOG gains section L: what is worth taking from Kong's AI Gateway, of
which this is the first.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>