Fix validate_project tool to handle directory paths and json import error

- Move json import to module level to fix NameError
- Add directory path handling to automatically find .kicad_pro files
- Improve error messages and validation logic
- Add proper file type validation

Fixes IsADirectoryError and 'json' variable access errors.

kicad_mcp/tools/analysis_tools.py

@@ -2,6 +2,7 @@
 Analysis and validation tools for KiCad projects.
 """
 
+import json
 import os
 from typing import Any
 
@@ -19,12 +20,49 @@ def register_analysis_tools(mcp: FastMCP) -> None:
 
     @mcp.tool()
     def validate_project(project_path: str) -> dict[str, Any]:
-        """Basic validation of a KiCad project."""
+        """Basic validation of a KiCad project.
+        
+        Args:
+            project_path: Path to the KiCad project file (.kicad_pro) or directory containing it
+        
+        Returns:
+            Dictionary with validation results
+        """
+        # Handle directory paths by looking for .kicad_pro file
+        if os.path.isdir(project_path):
+            # Look for .kicad_pro files in the directory
+            kicad_pro_files = [f for f in os.listdir(project_path) if f.endswith('.kicad_pro')]
+            if not kicad_pro_files:
+                return {
+                    "valid": False, 
+                    "error": f"No .kicad_pro file found in directory: {project_path}"
+                }
+            elif len(kicad_pro_files) > 1:
+                return {
+                    "valid": False,
+                    "error": f"Multiple .kicad_pro files found in directory: {project_path}. Please specify the exact file."
+                }
+            else:
+                project_path = os.path.join(project_path, kicad_pro_files[0])
+        
         if not os.path.exists(project_path):
-            return {"valid": False, "error": f"Project not found: {project_path}"}
+            return {"valid": False, "error": f"Project file not found: {project_path}"}
+        
+        if not project_path.endswith('.kicad_pro'):
+            return {
+                "valid": False, 
+                "error": f"Invalid file type. Expected .kicad_pro file, got: {project_path}"
+            }
 
         issues = []
-        files = get_project_files(project_path)
+        
+        try:
+            files = get_project_files(project_path)
+        except Exception as e:
+            return {
+                "valid": False,
+                "error": f"Error analyzing project files: {str(e)}"
+            }
 
         # Check for essential files
         if "pcb" not in files:
@@ -33,14 +71,12 @@ def register_analysis_tools(mcp: FastMCP) -> None:
         if "schematic" not in files:
             issues.append("Missing schematic file")
 
-        # Validate project file
+        # Validate project file JSON format
         try:
             with open(project_path) as f:
-                import json
-
                 json.load(f)
-        except json.JSONDecodeError:
+        except json.JSONDecodeError as e:
-            issues.append("Invalid project file format (JSON parsing error)")
+            issues.append(f"Invalid project file format (JSON parsing error): {str(e)}")
         except Exception as e:
             issues.append(f"Error reading project file: {str(e)}")