Anthropic count_tokens rejects generation-only fields such as temperature, top_p, top_k, stream, and stop sequences. Passing the original messages payload through unchanged can turn otherwise valid requests into upstream 400 errors.
Sanitize only the count_tokens upstream payload after the gateway's existing request normalization, preserving fields that existing compatibility paths rely on while removing parameters the count_tokens endpoint does not accept.
Fixes#2764
Co-authored-by: Cursor <cursoragent@cursor.com>
27600b1d2c