diff --git a/live_tracker.go b/live_tracker.go
index 40e1930..1d48e58 100644
--- a/live_tracker.go
+++ b/live_tracker.go
@@ -68,6 +68,11 @@ func (l *liveTracker) AddBuildDefDeps(def *buildDef) error {
 		return err
 	}
 
+	err = l.addNinjaStringListDeps(def.Validations)
+	if err != nil {
+		return err
+	}
+
 	for _, value := range def.Variables {
 		err = l.addNinjaStringDeps(value)
 		if err != nil {
diff --git a/ninja_defs.go b/ninja_defs.go
index c5d0e4b..8c5db57 100644
--- a/ninja_defs.go
+++ b/ninja_defs.go
@@ -87,6 +87,7 @@ type BuildParams struct {
 	Inputs          []string          // The list of explicit input dependencies.
 	Implicits       []string          // The list of implicit input dependencies.
 	OrderOnly       []string          // The list of order-only dependencies.
+	Validations     []string          // The list of validations to run when this rule runs.
 	Args            map[string]string // The variable/value pairs to set.
 	Optional        bool              // Skip outputting a default statement
 }
@@ -257,6 +258,7 @@ type buildDef struct {
 	Inputs          []ninjaString
 	Implicits       []ninjaString
 	OrderOnly       []ninjaString
+	Validations     []ninjaString
 	Args            map[Variable]ninjaString
 	Variables       map[string]ninjaString
 	Optional        bool
@@ -314,6 +316,11 @@ func parseBuildParams(scope scope, params *BuildParams) (*buildDef,
 		return nil, fmt.Errorf("error parsing OrderOnly param: %s", err)
 	}
 
+	b.Validations, err = parseNinjaStrings(scope, params.Validations)
+	if err != nil {
+		return nil, fmt.Errorf("error parsing Validations param: %s", err)
+	}
+
 	b.Optional = params.Optional
 
 	if params.Depfile != "" {
@@ -373,6 +380,7 @@ func (b *buildDef) WriteTo(nw *ninjaWriter, pkgNames map[*packageContext]string)
 		explicitDeps  = valueList(b.Inputs, pkgNames, inputEscaper)
 		implicitDeps  = valueList(b.Implicits, pkgNames, inputEscaper)
 		orderOnlyDeps = valueList(b.OrderOnly, pkgNames, inputEscaper)
+		validations   = valueList(b.Validations, pkgNames, inputEscaper)
 	)
 
 	if b.RuleDef != nil {
@@ -380,7 +388,7 @@ func (b *buildDef) WriteTo(nw *ninjaWriter, pkgNames map[*packageContext]string)
 		orderOnlyDeps = append(valueList(b.RuleDef.CommandOrderOnly, pkgNames, inputEscaper), orderOnlyDeps...)
 	}
 
-	err := nw.Build(comment, rule, outputs, implicitOuts, explicitDeps, implicitDeps, orderOnlyDeps)
+	err := nw.Build(comment, rule, outputs, implicitOuts, explicitDeps, implicitDeps, orderOnlyDeps, validations)
 	if err != nil {
 		return err
 	}
diff --git a/ninja_writer.go b/ninja_writer.go
index 5366f3f..5e69c08 100644
--- a/ninja_writer.go
+++ b/ninja_writer.go
@@ -104,7 +104,7 @@ func (n *ninjaWriter) Rule(name string) error {
 }
 
 func (n *ninjaWriter) Build(comment string, rule string, outputs, implicitOuts,
-	explicitDeps, implicitDeps, orderOnlyDeps []string) error {
+	explicitDeps, implicitDeps, orderOnlyDeps, validations []string) error {
 
 	n.justDidBlankLine = false
 
@@ -161,6 +161,14 @@ func (n *ninjaWriter) Build(comment string, rule string, outputs, implicitOuts,
 		}
 	}
 
+	if len(validations) > 0 {
+		wrapper.WriteStringWithSpace("|@")
+
+		for _, dep := range validations {
+			wrapper.WriteStringWithSpace(dep)
+		}
+	}
+
 	return wrapper.Flush()
 }
 
diff --git a/ninja_writer_test.go b/ninja_writer_test.go
index cc880e5..48ecb7c 100644
--- a/ninja_writer_test.go
+++ b/ninja_writer_test.go
@@ -50,9 +50,9 @@ var ninjaWriterTestCases = []struct {
 	{
 		input: func(w *ninjaWriter) {
 			ck(w.Build("foo comment", "foo", []string{"o1", "o2"}, []string{"io1", "io2"},
-				[]string{"e1", "e2"}, []string{"i1", "i2"}, []string{"oo1", "oo2"}))
+				[]string{"e1", "e2"}, []string{"i1", "i2"}, []string{"oo1", "oo2"}, []string{"v1", "v2"}))
 		},
-		output: "# foo comment\nbuild o1 o2 | io1 io2: foo e1 e2 | i1 i2 || oo1 oo2\n",
+		output: "# foo comment\nbuild o1 o2 | io1 io2: foo e1 e2 | i1 i2 || oo1 oo2 |@ v1 v2\n",
 	},
 	{
 		input: func(w *ninjaWriter) {
@@ -94,7 +94,7 @@ var ninjaWriterTestCases = []struct {
 			ck(w.ScopedAssign("command", "echo out: $out in: $in _arg: $_arg"))
 			ck(w.ScopedAssign("pool", "p"))
 			ck(w.BlankLine())
-			ck(w.Build("r comment", "r", []string{"foo.o"}, nil, []string{"foo.in"}, nil, nil))
+			ck(w.Build("r comment", "r", []string{"foo.o"}, nil, []string{"foo.in"}, nil, nil, nil))
 			ck(w.ScopedAssign("_arg", "arg value"))
 		},
 		output: `pool p