diff --git a/patchwork/steps/FixIssue/FixIssue.py b/patchwork/steps/FixIssue/FixIssue.py
index 7652ede25..bcb81e7a2 100644
--- a/patchwork/steps/FixIssue/FixIssue.py
+++ b/patchwork/steps/FixIssue/FixIssue.py
@@ -1,8 +1,10 @@
+import difflib
 import re
 from pathlib import Path
 from typing import Any, Optional
 
-from git import Repo
+from git import Repo, InvalidGitRepositoryError
+from patchwork.logger import logger
 from openai.types.chat import ChatCompletionMessageParam
 
 from patchwork.common.client.llm.aio import AioLlmClient
@@ -97,11 +99,31 @@ def is_stop(self, messages: list[ChatCompletionMessageParam]) -> bool:
 
 class FixIssue(Step, input_class=FixIssueInputs, output_class=FixIssueOutputs):
     def __init__(self, inputs):
+        """Initialize the FixIssue step.
+        
+        Args:
+            inputs: Dictionary containing input parameters including:
+                - base_path: Optional path to the repository root
+                - Other LLM-related parameters
+        """
         super().__init__(inputs)
-        self.base_path = inputs.get("base_path")
-        if self.base_path is None:
-            repo = Repo(Path.cwd(), search_parent_directories=True)
-            self.base_path = repo.working_tree_dir
+        cwd = str(Path.cwd())
+        original_base_path = inputs.get("base_path")
+
+        if original_base_path is not None:
+            original_base_path = str(Path(str(original_base_path)).resolve())
+
+        # Check if we're in a git repository
+        try:
+            self.repo = Repo(original_base_path or cwd, search_parent_directories=True)
+        except (InvalidGitRepositoryError, Exception):
+            self.repo = None
+
+        repo_working_dir = None
+        if self.repo is not None:
+            repo_working_dir = self.repo.working_dir
+
+        self.base_path = original_base_path or repo_working_dir or cwd
 
         llm_client = AioLlmClient.create_aio_client(inputs)
         if llm_client is None:
@@ -122,10 +144,40 @@ def __init__(self, inputs):
         )
 
     def run(self):
+        """Execute the FixIssue step.
+        
+        This method:
+        1. Executes the multi-turn LLM conversation to analyze and fix the issue
+        2. Tracks file modifications made by the CodeEditTool
+        3. Generates in-memory diffs for all modified files
+        
+        Returns:
+            dict: Dictionary containing list of modified files with their diffs
+        """
         self.multiturn_llm_call.execute(limit=100)
+
+        modified_files = []
+        cwd = Path.cwd()
         for tool in self.multiturn_llm_call.tool_set.values():
-            if isinstance(tool, CodeEditTool):
-                cwd = Path.cwd()
-                modified_files = [file_path.relative_to(cwd) for file_path in tool.tool_records["modified_files"]]
-                return dict(modified_files=[{"path": str(file)} for file in modified_files])
-        return dict()
+            if not isinstance(tool, CodeEditTool):
+                continue
+            tool_modified_files = [
+                dict(path=str(file_path.relative_to(cwd)), diff="")
+                for file_path in tool.tool_records["modified_files"]
+            ]
+            modified_files.extend(tool_modified_files)
+
+        # Generate diffs for modified files
+        # Only try to generate git diff if we're in a git repository
+        if self.repo is not None:
+            for modified_file in modified_files:
+                file = modified_file["path"]
+                try:
+                    # Try to get the diff using git
+                    diff = self.repo.git.diff('HEAD', file)
+                    modified_file["diff"] = diff or ""
+                except Exception as e:
+                    # Git-specific errors (untracked files, etc) - keep empty diff
+                    logger.warning(f"Could not get git diff for {file}: {str(e)}")
+
+        return dict(modified_files=modified_files)
diff --git a/patchwork/steps/FixIssue/typed.py b/patchwork/steps/FixIssue/typed.py
index 35732a6fa..2ead5452f 100644
--- a/patchwork/steps/FixIssue/typed.py
+++ b/patchwork/steps/FixIssue/typed.py
@@ -35,5 +35,21 @@ class FixIssueInputs(__FixIssueRequiredInputs, total=False):
     ]
 
 
+class ModifiedFile(TypedDict):
+    """Represents a file that has been modified by the FixIssue step.
+    
+    Attributes:
+        path: The relative path to the modified file from the repository root
+        diff: A unified diff string showing the changes made to the file.
+              Generated using Python's difflib to compare the original and
+              modified file contents in memory.
+    
+    Note:
+        The diff is generated by comparing file contents before and after
+        modifications, without relying on version control systems.
+    """
+    path: str
+    diff: str
+
 class FixIssueOutputs(TypedDict):
-    modified_files: List[Dict]
+    modified_files: List[ModifiedFile]
diff --git a/patchwork/steps/ModifyCode/ModifyCode.py b/patchwork/steps/ModifyCode/ModifyCode.py
index f7c6d7e4f..5f517c1e4 100644
--- a/patchwork/steps/ModifyCode/ModifyCode.py
+++ b/patchwork/steps/ModifyCode/ModifyCode.py
@@ -1,13 +1,21 @@
 from __future__ import annotations
 
+import difflib
 from pathlib import Path
 
+from patchwork.logger import logger
 from patchwork.step import Step, StepStatus
 
 
-def save_file_contents(file_path, content):
-    """Utility function to save content to a file."""
-    with open(file_path, "w") as file:
+def save_file_contents(file_path: str | Path, content: str) -> None:
+    """Utility function to save content to a file.
+    
+    Args:
+        file_path: Path to the file to save content to (str or Path)
+        content: Content to write to the file
+    """
+    path = Path(file_path)
+    with path.open("w") as file:
         file.write(content)
 
 
@@ -33,20 +41,26 @@ def handle_indent(src: list[str], target: list[str], start: int, end: int) -> li
 
 
 def replace_code_in_file(
-    file_path: str,
+    file_path: str | Path,
     start_line: int | None,
     end_line: int | None,
     new_code: str,
 ) -> None:
+    """Replace code in a file at the specified line range.
+    
+    Args:
+        file_path: Path to the file to modify (str or Path)
+        start_line: Starting line number (1-based)
+        end_line: Ending line number (1-based)
+        new_code: New code to insert
+    """
     path = Path(file_path)
     new_code_lines = new_code.splitlines(keepends=True)
     if len(new_code_lines) > 0 and not new_code_lines[-1].endswith("\n"):
         new_code_lines[-1] += "\n"
 
     if path.exists() and start_line is not None and end_line is not None:
-        """Replaces specified lines in a file with new code."""
         text = path.read_text()
-
         lines = text.splitlines(keepends=True)
 
         # Insert the new code at the start line after converting it into a list of lines
@@ -55,7 +69,7 @@ def replace_code_in_file(
         lines = new_code_lines
 
     # Save the modified contents back to the file
-    save_file_contents(file_path, "".join(lines))
+    save_file_contents(path, "".join(lines))
 
 
 class ModifyCode(Step):
@@ -81,7 +95,8 @@ def run(self) -> dict:
             return dict(modified_code_files=[])
 
         for code_snippet, extracted_response in sorted_list:
-            uri = code_snippet.get("uri")
+            # Use Path for consistent path handling
+            file_path = Path(code_snippet.get("uri", ""))
             start_line = code_snippet.get("startLine")
             end_line = code_snippet.get("endLine")
             new_code = extracted_response.get("patch")
@@ -89,8 +104,44 @@ def run(self) -> dict:
             if new_code is None:
                 continue
 
-            replace_code_in_file(uri, start_line, end_line, new_code)
-            modified_code_file = dict(path=uri, start_line=start_line, end_line=end_line, **extracted_response)
+            # Get the original content for diffing
+            diff = ""
+            try:
+                # Store original content in memory
+                original_content = file_path.read_text() if file_path.exists() else ""
+                
+                # Apply the changes
+                replace_code_in_file(file_path, start_line, end_line, new_code)
+                
+                # Read modified content
+                current_content = file_path.read_text() if file_path.exists() else ""
+                
+                # Generate unified diff
+                fromfile = f"a/{file_path}"
+                tofile = f"b/{file_path}"
+                diff = "".join(difflib.unified_diff(
+                    original_content.splitlines(keepends=True),
+                    current_content.splitlines(keepends=True),
+                    fromfile=fromfile,
+                    tofile=tofile
+                ))
+                
+                if not diff and new_code:  # If no diff but we have new code (new file)
+                    diff = f"+++ {file_path}\n{new_code}"
+            except (OSError, IOError) as e:
+                logger.warning(f"Failed to generate diff for {file_path}: {str(e)}")
+                # Still proceed with the modification even if diff generation fails
+                replace_code_in_file(file_path, start_line, end_line, new_code)
+                diff = f"+++ {file_path}\n{new_code}"  # Use new code as diff on error
+            
+            # Create the modified code file dictionary
+            modified_code_file = dict(
+                path=str(file_path),
+                start_line=start_line,
+                end_line=end_line,
+                diff=diff,
+                **extracted_response
+            )
             modified_code_files.append(modified_code_file)
 
         return dict(modified_code_files=modified_code_files)
diff --git a/patchwork/steps/ModifyCode/typed.py b/patchwork/steps/ModifyCode/typed.py
index 2cfba5e8f..6f26f79b4 100644
--- a/patchwork/steps/ModifyCode/typed.py
+++ b/patchwork/steps/ModifyCode/typed.py
@@ -11,6 +11,22 @@ class ModifyCodeOutputs(TypedDict):
 
 
 class ModifiedCodeFile(TypedDict, total=False):
+    """Represents a file that has been modified by the ModifyCode step.
+    
+    Attributes:
+        path: The path to the modified file
+        start_line: The starting line number of the modification (1-based)
+        end_line: The ending line number of the modification (1-based)
+        diff: A unified diff string showing the changes made to the file.
+              Generated using Python's difflib for in-memory comparison
+              of original and modified file contents.
+    
+    Note:
+        The diff field is generated using difflib.unified_diff() to compare
+        the original and modified file contents in memory, ensuring efficient
+        and secure diff generation.
+    """
     path: str
     start_line: int
     end_line: int
+    diff: str
diff --git a/pyproject.toml b/pyproject.toml
index aa7a33390..9d5da77d1 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "patchwork-cli"
-version = "0.0.90"
+version = "0.0.91"
 description = ""
 authors = ["patched.codes"]
 license = "AGPL"