feat(mma): Optimize sub-agent research with get_code_outline and get_git_diff

mcp_client.py

@@ -281,6 +281,31 @@ def get_code_outline(path: str) -> str:
         return f"ERROR generating outline for '{path}': {e}"
 
 
+def get_git_diff(path: str, base_rev: str = "HEAD", head_rev: str = "") -> str:
+    """
+    Returns the git diff for a file or directory.
+    base_rev: The base revision (default: HEAD)
+    head_rev: The head revision (optional)
+    """
+    import subprocess
+    p, err = _resolve_and_check(path)
+    if err:
+        return err
+    
+    cmd = ["git", "diff", base_rev]
+    if head_rev:
+        cmd.append(head_rev)
+    cmd.extend(["--", str(p)])
+    
+    try:
+        result = subprocess.run(cmd, capture_output=True, text=True, check=True, encoding="utf-8")
+        return result.stdout if result.stdout else "(no changes)"
+    except subprocess.CalledProcessError as e:
+        return f"ERROR running git diff: {e.stderr}"
+    except Exception as e:
+        return f"ERROR: {e}"
+
+
 
 # ------------------------------------------------------------------ web tools
 
@@ -407,7 +432,7 @@ def get_ui_performance() -> str:
 # ------------------------------------------------------------------ tool dispatch
 
 
-TOOL_NAMES = {"read_file", "list_directory", "search_files", "get_file_summary", "get_python_skeleton", "get_code_outline", "web_search", "fetch_url", "get_ui_performance"}
+TOOL_NAMES = {"read_file", "list_directory", "search_files", "get_file_summary", "get_python_skeleton", "get_code_outline", "get_git_diff", "web_search", "fetch_url", "get_ui_performance"}
 
 
 def dispatch(tool_name: str, tool_input: dict) -> str:
@@ -426,6 +451,12 @@ def dispatch(tool_name: str, tool_input: dict) -> str:
         return get_python_skeleton(tool_input.get("path", ""))
     if tool_name == "get_code_outline":
         return get_code_outline(tool_input.get("path", ""))
+    if tool_name == "get_git_diff":
+        return get_git_diff(
+            tool_input.get("path", ""), 
+            tool_input.get("base_rev", "HEAD"), 
+            tool_input.get("head_rev", "")
+        )
     if tool_name == "web_search":
         return web_search(tool_input.get("query", ""))
     if tool_name == "fetch_url":
@@ -551,6 +582,31 @@ MCP_TOOL_SPECS = [
             "required": ["path"],
         },
     },
+    {
+        "name": "get_git_diff",
+        "description": (
+            "Returns the git diff for a file or directory. "
+            "Use this to review changes efficiently without reading entire files."
+        ),
+        "parameters": {
+            "type": "object",
+            "properties": {
+                "path": {
+                    "type": "string",
+                    "description": "Path to the file or directory.",
+                },
+                "base_rev": {
+                    "type": "string",
+                    "description": "Base revision (e.g. 'HEAD', 'HEAD~1', or a commit hash). Defaults to 'HEAD'.",
+                },
+                "head_rev": {
+                    "type": "string",
+                    "description": "Head revision (optional).",
+                }
+            },
+            "required": ["path"],
+        },
+    },
     {
         "name": "web_search",
         "description": "Search the web using DuckDuckGo. Returns the top 5 search results with titles, URLs, and snippets. Chain this with fetch_url to read specific pages.",