fix(git): accept JSON-encoded string for git_add files argument

src/git/src/mcp_server_git/server.py

@@ -1,3 +1,4 @@
+import json
 import logging
 from pathlib import Path
 from typing import Sequence, Optional
@@ -42,7 +43,10 @@ class GitCommit(BaseModel):
 
 class GitAdd(BaseModel):
     repo_path: str
-    files: list[str]
+    files: list[str] | str = Field(
+        ...,
+        description="The files to stage. Normally a list of paths. A JSON-encoded array string such as '[\"a.py\", \"b.py\"]' or a single path string are also accepted for leniency.",
+    )
 
 class GitReset(BaseModel):
     repo_path: str
@@ -129,7 +133,23 @@ def git_commit(repo: git.Repo, message: str) -> str:
     commit = repo.index.commit(message)
     return f"Changes committed successfully with hash {commit.hexsha}"
 
-def git_add(repo: git.Repo, files: list[str]) -> str:
+def normalize_file_list(files: list[str] | str) -> list[str]:
+    # Some clients send the files argument as a JSON-encoded array string,
+    # e.g. '["a.py", "b.py"]', instead of a real array. Accept that form, and
+    # also accept a single bare path string, so a stray string does not fail
+    # the call outright.
+    if isinstance(files, str):
+        try:
+            parsed = json.loads(files)
+        except json.JSONDecodeError:
+            return [files]
+        if isinstance(parsed, list) and all(isinstance(item, str) for item in parsed):
+            return parsed
+        return [files]
+    return files
+
+def git_add(repo: git.Repo, files: list[str] | str) -> str:
+    files = normalize_file_list(files)
     if files == ["."]:
         repo.git.add(".")
     else:

src/git/tests/test_server.py

@@ -6,6 +6,7 @@
     git_checkout,
     git_branch,
     git_add,
+    normalize_file_list,
     git_status,
     git_diff_unstaged,
     git_diff_staged,
@@ -109,6 +110,45 @@ def test_git_add_specific_files(test_repository):
     assert "file2.txt" not in staged_files
     assert result == "Files staged successfully"
 
+def test_git_add_json_encoded_string(test_repository):
+    file1 = Path(test_repository.working_dir) / "file1.txt"
+    file2 = Path(test_repository.working_dir) / "file2.txt"
+    file1.write_text("file 1 content")
+    file2.write_text("file 2 content")
+
+    # Some clients send the files argument as a JSON-encoded array string.
+    result = git_add(test_repository, '["file1.txt", "file2.txt"]')
+
+    staged_files = [item.a_path for item in test_repository.index.diff("HEAD")]
+    assert "file1.txt" in staged_files
+    assert "file2.txt" in staged_files
+    assert result == "Files staged successfully"
+
+def test_git_add_single_path_string(test_repository):
+    file1 = Path(test_repository.working_dir) / "file1.txt"
+    file2 = Path(test_repository.working_dir) / "file2.txt"
+    file1.write_text("file 1 content")
+    file2.write_text("file 2 content")
+
+    # A single bare path string is treated as one file, not split apart.
+    result = git_add(test_repository, "file1.txt")
+
+    staged_files = [item.a_path for item in test_repository.index.diff("HEAD")]
+    assert "file1.txt" in staged_files
+    assert "file2.txt" not in staged_files
+    assert result == "Files staged successfully"
+
+def test_normalize_file_list():
+    # Real lists pass through unchanged.
+    assert normalize_file_list(["a.py", "b.py"]) == ["a.py", "b.py"]
+    # JSON-encoded array strings are parsed into a list.
+    assert normalize_file_list('["a.py", "b.py"]') == ["a.py", "b.py"]
+    # A bare path that is not valid JSON is kept as a single entry.
+    assert normalize_file_list("a.py") == ["a.py"]
+    # A JSON value that is not a list of strings is treated as a single path.
+    assert normalize_file_list('{"a": 1}') == ['{"a": 1}']
+    assert normalize_file_list("[1, 2]") == ["[1, 2]"]
+
 def test_git_status(test_repository):
     result = git_status(test_repository)