feat: improve run command error output for missing workflow inputs

pkg/cli/run_input_validation_test.go

@@ -116,11 +116,12 @@ jobs:
 
 func TestValidateWorkflowInputs(t *testing.T) {
 	tests := []struct {
-		name           string
-		lockContent    string
-		providedInputs []string
-		expectError    bool
-		errorContains  []string // strings that should be in the error message
+		name             string
+		lockContent      string
+		providedInputs   []string
+		expectError      bool
+		errorContains    []string // strings that should be in the error message
+		errorNotContains []string // strings that should NOT be in the error message
 	}{
 		{
 			name: "all required inputs provided",
@@ -159,7 +160,53 @@ jobs:
 `,
 			providedInputs: []string{},
 			expectError:    true,
-			errorContains:  []string{"Missing required input(s)", "issue_url"},
+			errorContains:  []string{"Missing required input(s)", "issue_url", "gh aw run test-workflow -F issue_url=<value>"},
+		},
+		{
+			name: "required input with default value - should not error when missing",
+			lockContent: `name: "Test Workflow"
+on:
+  workflow_dispatch:
+    inputs:
+      release_type:
+        description: 'Release type'
+        required: true
+        default: patch
+        type: string
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - run: echo "test"
+`,
+			providedInputs: []string{},
+			expectError:    false,
+		},
+		{
+			name: "required input with default shown in valid inputs list",
+			lockContent: `name: "Test Workflow"
+on:
+  workflow_dispatch:
+    inputs:
+      missing_required:
+        description: 'Must be set'
+        required: true
+        type: string
+      defaulted:
+        description: 'Has a default'
+        required: true
+        default: patch
+        type: string
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - run: echo "test"
+`,
+			providedInputs:   []string{},
+			expectError:      true,
+			errorContains:    []string{"Missing required input(s)", "missing_required", "default: patch"},
+			errorNotContains: []string{"gh aw run test-workflow -F defaulted=<value>"},
 		},
 		{
 			name: "typo in input name",
@@ -290,6 +337,11 @@ jobs:
 							t.Errorf("Expected error to contain '%s', but got: %s", expected, errStr)
 						}
 					}
+					for _, notExpected := range tt.errorNotContains {
+						if strings.Contains(errStr, notExpected) {
+							t.Errorf("Expected error NOT to contain '%s', but got: %s", notExpected, errStr)
+						}
+					}
 				}
 			} else {
 				if err != nil {

pkg/cli/run_workflow_validation.go

@@ -186,10 +186,10 @@ func validateWorkflowInputs(markdownPath string, providedInputs []string) error
 		}
 	}
 
-	// Check for required inputs that are missing
+	// Check for required inputs that are missing (ignore inputs with a default value)
 	var missingInputs []string
 	for inputName, inputDef := range workflowInputs {
-		if inputDef.Required {
+		if inputDef.Required && inputDef.Default == nil {
 			if _, exists := providedInputsMap[inputName]; !exists {
 				missingInputs = append(missingInputs, inputName)
 			}
@@ -231,18 +231,39 @@ func validateWorkflowInputs(markdownPath string, providedInputs []string) error
 		// Add helpful information about valid inputs
 		if len(workflowInputs) > 0 {
 			var inputDescriptions []string
-			for name, def := range workflowInputs {
+			sortedNames := slices.Sorted(maps.Keys(workflowInputs))
+			for _, name := range sortedNames {
+				def := workflowInputs[name]
 				required := ""
-				if def.Required {
+				if def.Required && def.Default == nil {
 					required = " (required)"
 				}
 				desc := ""
 				if def.Description != "" {
 					desc = ": " + def.Description
 				}
-				inputDescriptions = append(inputDescriptions, fmt.Sprintf("  %s%s%s", name, required, desc))
+				defaultStr := ""
+				if def.Default != nil {
+					defaultStr = fmt.Sprintf(" [default: %s]", def.GetDefaultAsString())
+				}
+				inputDescriptions = append(inputDescriptions, fmt.Sprintf("  %s%s%s%s", name, required, desc, defaultStr))
+			}
+
+			// Derive the workflow name for the syntax hint
+			workflowName := strings.TrimSuffix(filepath.Base(markdownPath), ".md")
+			var syntaxExamples []string
+			for _, name := range sortedNames {
+				def := workflowInputs[name]
+				if def.Required && def.Default == nil {
+					syntaxExamples = append(syntaxExamples, fmt.Sprintf("  gh aw run %s -F %s=<value>", workflowName, name))
+				}
+			}
+
+			validInputsMsg := "\nValid inputs:\n" + strings.Join(inputDescriptions, "\n")
+			if len(syntaxExamples) > 0 {
+				validInputsMsg += "\n\nTo set required inputs, use:\n" + strings.Join(syntaxExamples, "\n")
 			}
-			errorParts = append(errorParts, "\nValid inputs:\n"+strings.Join(inputDescriptions, "\n"))
+			errorParts = append(errorParts, validInputsMsg)
 		}
 
 		return fmt.Errorf("%s", strings.Join(errorParts, "\n\n"))