fixup! fixup! Add Docker usage instructions to README

internal/server/handlers_edit.go

@@ -11,6 +11,17 @@ import (
 	"github.com/mark3labs/mcp-go/mcp"
 )
 
+// unescapeNewlines converts literal \n, \t, \" sequences to actual characters.
+// This handles cases where MCP clients send double-escaped JSON strings.
+func unescapeNewlines(s string) string {
+	// Replace common escape sequences
+	s = strings.ReplaceAll(s, "\\n", "\n")
+	s = strings.ReplaceAll(s, "\\t", "\t")
+	s = strings.ReplaceAll(s, "\\\"", "\"")
+	s = strings.ReplaceAll(s, "\\\\", "\\")
+	return s
+}
+
 // handleEditPreview handles the edit_preview tool.
 func (s *Server) handleEditPreview(ctx context.Context, request mcp.CallToolRequest) (*mcp.CallToolResult, error) {
 	return s.handleEdit(ctx, request, false)
@@ -52,10 +63,15 @@ func (s *Server) handleEdit(ctx context.Context, request mcp.CallToolRequest, ap
 	// The edit engine automatically detects whether to use AST or text mode.
 
 	// Build edit request with both AST and text-mode selectors
+	newContent := request.GetString("new_content", "")
+
+	// Unescape common escape sequences that may be double-encoded by MCP clients
+	newContent = unescapeNewlines(newContent)
+
 	astEdit := &edit.ASTEdit{
 		File:       file,
 		Operation:  edit.EditOperation(operation),
-		NewContent: request.GetString("new_content", ""),
+		NewContent: newContent,
 		Selector: edit.ASTSelector{
 			// AST-mode selectors
 			Kind:   request.GetString("selector_kind", ""),

internal/server/handlers_edit_test.go

@@ -0,0 +1,47 @@
+package server
+
+import "testing"
+
+func TestUnescapeNewlines(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		expected string
+	}{
+		{
+			name:     "no escapes",
+			input:    "func test() {\n\treturn true;\n}",
+			expected: "func test() {\n\treturn true;\n}",
+		},
+		{
+			name:     "literal backslash n",
+			input:    "func test() {\\n\\treturn true;\\n}",
+			expected: "func test() {\n\treturn true;\n}",
+		},
+		{
+			name:     "literal backslash t",
+			input:    "func test() {\\n\\treturn true;\\n}",
+			expected: "func test() {\n\treturn true;\n}",
+		},
+		{
+			name:     "literal quotes",
+			input:    `func test() {\n\treturn \"true\";\n}`,
+			expected: "func test() {\n\treturn \"true\";\n}",
+		},
+
+		{
+			name:     "mixed content",
+			input:    "line1\\nline2\\tindented\\nline3",
+			expected: "line1\nline2\tindented\nline3",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := unescapeNewlines(tt.input)
+			if result != tt.expected {
+				t.Errorf("unescapeNewlines(%q) = %q, expected %q", tt.input, result, tt.expected)
+			}
+		})
+	}
+}