promtool

promtool is Prometheus's utility CLI for checking, querying, testing, and debugging monitoring setups from the shell. It sits around a Prometheus deployment rather than replacing the server, giving you direct commands for validation, inspection, and TSDB-level maintenance tasks.

• Validate Prometheus config files, rule files, web config, and discovered targets before rollout or in CI.
• Query a Prometheus server, check health and readiness, inspect label values or series, and fetch debug data from the terminal.
• Lint scraped metrics, unit test alerting or recording rules, dump or analyze TSDB blocks, and backfill blocks from OpenMetrics or recording rules.

• promtool query can emit JSON, and most commands use stable flags, stdout, and exit codes that fit unattended validation and follow-up parsing.
• It works well in inspect, change, verify loops around Prometheus because agents can check configs, run rule tests, query live data, and inspect TSDB state without opening the UI.
• Coverage is narrower than a general infrastructure CLI: many commands are read-only diagnostics, and server-facing actions depend on reachable Prometheus endpoints or local TSDB files.

• Some useful surfaces are explicitly experimental, including promql editing and parts of the TSDB tooling.
• The recommended install path in the repo is released binaries from prometheus.io, so the current go install entry is more of a build path than the main end-user install flow.