initial file_str_replace implementation

ra_aid/__main__.py

@@ -15,7 +15,8 @@ from ra_aid.tools import (
     emit_research_notes, emit_plan, emit_related_files, emit_task,
     emit_expert_context, get_memory_value, emit_key_facts, delete_key_facts,
     emit_key_snippets, delete_key_snippets,
-    emit_research_subtask, request_implementation, read_file_tool, fuzzy_find_project_files, ripgrep_search, list_directory_tree
+    emit_research_subtask, request_implementation, read_file_tool, fuzzy_find_project_files, ripgrep_search, list_directory_tree,
+    file_str_replace
 )
 from ra_aid.tools.memory import _global_memory, get_related_files
 from ra_aid import print_agent_output, print_stage_header, print_task_header, print_error
@@ -38,7 +39,8 @@ COMMON_TOOLS = [
     delete_key_snippets,
     read_file_tool,
     fuzzy_find_project_files,
-    ripgrep_search
+    ripgrep_search,
+    file_str_replace
 ]
 
 # Expert-specific tools

ra_aid/tools/__init__.py

@@ -2,6 +2,7 @@ from .shell import run_shell_command
 from .programmer import run_programming_task
 from .expert import ask_expert, emit_expert_context
 from .read_file import read_file_tool
+from .file_str_replace import file_str_replace
 from .fuzzy_find import fuzzy_find_project_files
 from .list_directory import list_directory_tree
 from .ripgrep import ripgrep_search
@@ -31,5 +32,6 @@ __all__ = [
     'run_shell_command',
     'skip_implementation',
     'emit_research_subtask',
-    'ripgrep_search'
+    'ripgrep_search',
+    'file_str_replace'
 ]

ra_aid/tools/file_str_replace.py

@@ -0,0 +1,46 @@
+from langchain_core.tools import tool
+from typing import Dict
+from pathlib import Path
+
+@tool
+def file_str_replace(
+    filepath: str,
+    old_str: str,
+    new_str: str
+) -> Dict[str, any]:
+    """Replace an exact string match in a file with a new string.
+    Only performs replacement if the old string appears exactly once.
+    
+    Args:
+        filepath: Path to the file to modify
+        old_str: Exact string to replace
+        new_str: String to replace with
+        
+    Returns:
+        Dict containing:
+            - success: Whether the operation succeeded
+            - message: Success confirmation or error details
+    """
+    try:
+        path = Path(filepath)
+        if not path.exists():
+            return {"success": False, "message": f"File not found: {filepath}"}
+            
+        content = path.read_text()
+        count = content.count(old_str)
+        
+        if count == 0:
+            return {"success": False, "message": f"String not found: {old_str}"}
+        elif count > 1:
+            return {"success": False, "message": f"String appears {count} times - must be unique"}
+            
+        new_content = content.replace(old_str, new_str)
+        path.write_text(new_content)
+        
+        return {
+            "success": True,
+            "message": f"Successfully replaced '{old_str}' with '{new_str}' in {filepath}"
+        }
+        
+    except Exception as e:
+        return {"success": False, "message": f"Error: {str(e)}"}