fix: schema validation errors report correct line number and cleaner message prefix

pkg/workflow/compiler.go

@@ -443,8 +443,20 @@ func (c *Compiler) generateAndValidateYAML(workflowData *WorkflowData, markdownP
 	if !c.skipValidation {
 		log.Print("Validating workflow against GitHub Actions schema")
 		if err := c.validateGitHubActionsSchema(yamlContent); err != nil {
+			// Try to point at the exact line of the failing field in the source markdown.
+			// extractSchemaErrorField unwraps the error chain to find the top-level field
+			// name (e.g. "timeout-minutes"), which findFrontmatterFieldLine then locates in
+			// the source frontmatter so the error is IDE-navigable.
+			fieldLine := 1
+			if fieldName := extractSchemaErrorField(err); fieldName != "" {
+				frontmatterLines := strings.Split(workflowData.FrontmatterYAML, "\n")
+				if line := findFrontmatterFieldLine(frontmatterLines, 2, fieldName); line > 0 {
+					fieldLine = line
+				}
+			}
 			// Store error first so we can write invalid YAML before returning
-			formattedErr := formatCompilerError(markdownPath, "error", fmt.Sprintf("workflow schema validation failed: %v", err), err)
+			formattedErr := formatCompilerErrorWithPosition(markdownPath, fieldLine, 1, "error",
+				fmt.Sprintf("invalid workflow: %v", err), err)
 			// Write the invalid YAML to a .invalid.yml file for inspection
 			invalidFile := strings.TrimSuffix(lockFile, ".lock.yml") + ".invalid.yml"
 			if writeErr := os.WriteFile(invalidFile, []byte(yamlContent), 0644); writeErr == nil {

pkg/workflow/schema_validation.go

@@ -154,6 +154,21 @@ func extractFieldPath(location []string) string {
 	return location[len(location)-1] // Return the last element as the field name
 }
 
+// extractSchemaErrorField extracts the top-level field name from a schema validation error.
+// It unwraps the error chain to find a *jsonschema.ValidationError and returns the first
+// element of InstanceLocation, which is the top-level frontmatter key (e.g. "timeout-minutes").
+// Returns "" if no field name can be extracted.
+func extractSchemaErrorField(err error) string {
+	var ve *jsonschema.ValidationError
+	if !errors.As(err, &ve) {
+		return ""
+	}
+	if len(ve.InstanceLocation) == 0 {
+		return ""
+	}
+	return ve.InstanceLocation[0] // top-level field name
+}
+
 // getFieldExample returns an example for the given field based on the validation error
 func getFieldExample(fieldPath string, err error) string {
 	// Map of common fields to their examples

pkg/workflow/schema_validation_test.go

@@ -3,8 +3,12 @@
 package workflow
 
 import (
+	"errors"
+	"fmt"
 	"strings"
 	"testing"
+
+	"github.com/santhosh-tekuri/jsonschema/v6"
 )
 
 func TestExtractFieldPath(t *testing.T) {
@@ -236,3 +240,47 @@ jobs:
 		})
 	}
 }
+
+func TestExtractSchemaErrorField(t *testing.T) {
+	tests := []struct {
+		name     string
+		err      error
+		expected string
+	}{
+		{
+			name: "top-level field from ValidationError",
+			err: fmt.Errorf("wrapped: %w", &jsonschema.ValidationError{
+				InstanceLocation: []string{"timeout-minutes"},
+			}),
+			expected: "timeout-minutes",
+		},
+		{
+			name: "nested field returns top-level",
+			err: fmt.Errorf("wrapped: %w", &jsonschema.ValidationError{
+				InstanceLocation: []string{"jobs", "build", "runs-on"},
+			}),
+			expected: "jobs",
+		},
+		{
+			name:     "non-ValidationError returns empty",
+			err:      errors.New("some other error"),
+			expected: "",
+		},
+		{
+			name: "ValidationError with empty location returns empty",
+			err: fmt.Errorf("wrapped: %w", &jsonschema.ValidationError{
+				InstanceLocation: []string{},
+			}),
+			expected: "",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := extractSchemaErrorField(tt.err)
+			if result != tt.expected {
+				t.Errorf("extractSchemaErrorField() = %q, want %q", result, tt.expected)
+			}
+		})
+	}
+}