go tool: Usage, Options & Common CI Errors

Run the lower-level tools shipped with the Go toolchain.

go tool runs the compiler’s auxiliary programs: pprof for profiling, cover for coverage reports, trace for execution traces, and more. In CI it most often turns a coverage profile into a summary or HTML.

What it does

Dispatches to a named tool installed with the Go toolchain. Running go tool with no argument lists the available tools for your platform.

Common usage

go test -coverprofile=cover.out ./...
go tool cover -func=cover.out     # per-function coverage summary
go tool cover -html=cover.out -o coverage.html
go tool pprof cpu.prof            # analyze a CPU profile

Common CI error: unknown tool

go tool foo fails with "go: no such tool foo" when the name is wrong or the tool is not bundled (e.g. stringer, which is installed separately). Fix: run go tool to list valid tools; install standalone tools with go install <path>@version and invoke them directly, not via go tool.

Common tools

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