> For a complete page index of the Captain API documentation, fetch https://docs.captain.dev/llms.txt?excludeSpec=true

# Query Latency Metrics

* **Latency over a period in one call**: [Get Query Latency](/reference/queries/latency) returns exact p50, p95 and p99 for every query matching your filters, a histogram with bin edges, and the same bins per collection. This used to mean paging [List Queries](/reference/queries/list) a hundred records at a time. Response size follows the number of bins, and windows cover up to 90 days.
* **Unrecorded times are counted, not averaged in**: `measured` and `missing` are reported separately, so a query with no timing stays out of the percentiles instead of counting as zero.
* **Filters say when a setting was never recorded**: filter by collection, environment, API version, rerank, search mode or metadata filter; each accepts `unknown` for queries that predate the field, and `coverage` reports what share recorded it.
* **Find the slow ones**: [List Slowest Queries](/reference/queries/latency/slowest) returns durations and identifiers that open in [Get Query](/reference/queries/get); [List Latency Collections](/reference/queries/latency/collections) pages the collections active in a window. Guide: [Query latency](/guides/query-latency). The hosted [MCP server](/guides/mcp) adds `captain_get_query_latency`.