diff --git a/format.go b/format.go
index 58cd0ef..c12661a 100644
--- a/format.go
+++ b/format.go
@@ -6,6 +6,60 @@ import (
 )
 
 const (
+	// CommandBuild build a derivation or fetch a store path
+	CommandBuild = "build"
+
+	// FlagDryRun show what this command would do without doing it.
+	FlagDryRun = "--dry-run"
+	// FlagJson produce output in JSON format, suitable for consumption by another program.
+	FlagJson = "--json"
+	// FlagNoLink do not create symlinks to the build results.
+	FlagNoLink = "--no-link"
+	// FlagOutLink use path as prefix for the symlinks to the build results. It defaults to result.
+	FlagOutLink = "--out-link"
+	// FlagPrintOutPaths print the resulting output paths
+	FlagPrintOutPaths = "--print-out-paths"
+	// FlagProfile the profile to operate on.
+	FlagProfile = "--profile"
+	// FlagRebuild rebuild an already built package and compare the result to the existing store paths.
+	FlagRebuild = "--rebuild"
+	// FlagStdin read installables from the standard input. No default installable applied.
+	FlagStdin = "--stdin"
+
+	// FlagDebug set the logging verbosity level to 'debug'.
+	FlagDebug = "--debug"
+	// FlagLogFormat set the format of log output; one of raw, internal-json, bar or bar-with-logs.
+	FlagLogFormat = "--log-format"
+	// FlagPrintBuildLogs print full build logs on standard error.
+	FlagPrintBuildLogs = "--print-build-logs"
+	// FlagQuiet decrease the logging verbosity level.
+	FlagQuiet = "--quiet"
+	// FlagVerbose increase the logging verbosity level.
+	FlagVerbose = "--verbose"
+
+	// FlagOffline disable substituters and consider all previously downloaded files up-to-date.
+	FlagOffline = "--offline"
+	// FlagOption set the Nix configuration setting name to value (overriding nix.conf).
+	FlagOption = "--option"
+	// FlagRefresh consider all previously downloaded files out-of-date.
+	FlagRefresh = "--refresh"
+	// FlagRepair during evaluation, rewrite missing or corrupted files in the Nix store. During building, rebuild missing or corrupted store paths.
+	FlagRepair = "--repair"
+	// FlagVersion show version information.
+	FlagVersion = "--version"
+
+	// OptionEvalCache whether to use the flake evaluation cache.
+	// Certain commands won’t have to evaluate when invoked for the second time with a particular version of a flake.
+	// Intermediate results are not cached.
+	OptionEvalCache = "eval-cache"
+
+	ValueTrue  = "true"
+	ValueFalse = "false"
+)
+
+const (
+	nix = "nix"
+
 	nixExtraExperimentalFeatures  = "--extra-experimental-features"
 	nixExperimentalFeaturesFlakes = "nix-command flakes"
 )
@@ -15,7 +69,7 @@ var nixEnableFlakes = []string{nixExtraExperimentalFeatures, nixExperimentalFeat
 
 // Nix returns the [exec.Cmd] struct to execute a nix command.
 func Nix(ctx context.Context, arg ...string) *exec.Cmd {
-	return exec.CommandContext(ctx, "nix", append(nixEnableFlakes, arg...)...)
+	return exec.CommandContext(ctx, nix, append(nixEnableFlakes, arg...)...)
 }
 
 const (
diff --git a/instantiated.go b/instantiated.go
index d739ca9..f11230e 100644
--- a/instantiated.go
+++ b/instantiated.go
@@ -149,13 +149,13 @@ func (e *InstantiatedEvaluator) Err() error {
 func NewInstantiatedEvaluator(ctx context.Context, installable string) (*InstantiatedEvaluator, error) {
 	c, cancel := context.WithCancel(ctx)
 	e := &InstantiatedEvaluator{
-		cmd: Nix(c, "build", installable,
+		cmd: Nix(c, CommandBuild, installable,
 			// 'instantiated' messages are only emitted when actually evaluating something
-			"--option", "eval-cache", "false",
+			FlagOption, OptionEvalCache, ValueFalse,
 			// do not actually build anything
-			"--dry-run",
+			FlagDryRun,
 			// increase verbosity so nix outputs 'instantiated' messages
-			"-Lvvv",
+			FlagPrintBuildLogs, FlagDebug,
 		),
 		cancel: cancel,
 	}