The search/filtering syntax for searching spans in the Phoenix web UI uses Python boolean expressions, such as `span_kind == 'LLM'`. This syntax is documented at <https://arize.com/docs/phoenix/tracing/how-to-tracing/extract-data-from-spans#how-to-apply-filters-ui|this page>, which provides examples and explains that the same expressions used in the `.where()` method of the Python SDK can be entered directly into the UI search bar.
You can filter on span attributes, use logical operators like `and`, and perform substring searches with the `in` operator. However, filtering is only applied to each span itself, not to child spans, and some advanced features (like filtering by event parameters) are not currently supported in the UI. Would you like more detail or code examples?
Sources:
- <https://arize.com/docs/phoenix/tracing/how-to-tracing/extract-data-from-spans#how-to-apply-filters-ui|How to Apply Filters (UI)>
- <https://arize-ai.slack.com/archives/C04R3GXC8HK/p1721253355.764669|Slack discussion: search/filtering syntax and child span limitations>
