diff --git a/internal/cli/runtime.go b/internal/cli/runtime.go
index c4725a3..2e3e659 100644
--- a/internal/cli/runtime.go
+++ b/internal/cli/runtime.go
@@ -7,6 +7,7 @@ package cli
 import (
 	"io"
 	"os"
+	"strings"
 
 	"golang.org/x/term"
 )
@@ -101,3 +102,14 @@ func (r Runtime) SetVerbose(verbose bool) {
 		r.setVerbose(verbose)
 	}
 }
+
+// EnvValue returns the value and presence of one environment entry.
+func (r Runtime) EnvValue(name string) (string, bool) {
+	prefix := name + "="
+	for _, entry := range r.environment {
+		if strings.HasPrefix(entry, prefix) {
+			return strings.TrimPrefix(entry, prefix), true
+		}
+	}
+	return "", false
+}
diff --git a/internal/cli/runtime_test.go b/internal/cli/runtime_test.go
index 2f16142..d087095 100644
--- a/internal/cli/runtime_test.go
+++ b/internal/cli/runtime_test.go
@@ -14,6 +14,7 @@ func TestCLIRuntime(t *testing.T) {
 		{"stream defaults", testRuntimeStreams},
 		{"terminal predicates", testRuntimeTerminal},
 		{"verbosity callback", testRuntimeVerbose},
+		{"environment lookup", testRuntimeEnvValue},
 		{"instance isolation", testRuntimeIsolation},
 	}
 	for _, scenario := range scenarios {
@@ -76,6 +77,17 @@ func testRuntimeVerbose(t *testing.T) {
 	}
 }
 
+func testRuntimeEnvValue(t *testing.T) {
+	runtime, _, _ := runtimeFixture(t, []string{"CATTERY_REPO=repo", "OTHER=x"}, nil)
+	value, present := runtime.EnvValue("CATTERY_REPO")
+	if !present || value != "repo" {
+		t.Fatalf("CATTERY_REPO = %q present = %v, want repo true", value, present)
+	}
+	if _, present := runtime.EnvValue("MISSING"); present {
+		t.Fatal("a missing variable must report absent")
+	}
+}
+
 func testRuntimeIsolation(t *testing.T) {
 	first, _, _ := runtimeFixture(t, []string{"A=1", "B=2"}, nil)
 	second, _, _ := runtimeFixture(t, []string{"C=3"}, nil)