MCP Git Server

git_diff

Compare changes between Git branches or commits to review modifications before merging or deploying code.

Instructions

Shows differences between branches or commits

Input Schema

TableJSON Schema

Name	Required	Description	Default
`repo_path`	Yes
`target`	Yes

Implementation Reference

src/mcp_server_git/server.py:86-88 (handler)
Core handler function that computes the git diff against the specified target using repo.git.diff(target). Called by the MCP tool dispatcher.
```
def git_diff(repo: git.Repo, target: str) -> str:
    return repo.git.diff(target)
```
src/mcp_server_git/server.py:28-30 (schema)
Pydantic input schema for the git_diff tool, defining repo_path and target parameters.
```
class GitDiff(BaseModel):
    repo_path: str
    target: str
```
src/mcp_server_git/server.py:186-190 (registration)
Registration of the 'git_diff' tool (GitTools.DIFF) in the list_tools() method, including name, description, and input schema.
```
Tool(
    name=GitTools.DIFF,
    description="Shows differences between branches or commits",
    inputSchema=GitDiff.schema(),
),
```

src/mcp_server_git/server.py:299-304 (handler)

MCP call_tool dispatcher case for git_diff: extracts target, calls git_diff helper, formats and returns TextContent response.

case GitTools.DIFF:
    diff = git_diff(repo, arguments["target"])
    return [TextContent(
        type="text",
        text=f"Diff with {arguments['target']}:\n{diff}"
    )]

src/mcp_server_git/server.py:63-75 (helper)

Enum definition providing the tool name constant GitTools.DIFF = "git_diff" used in registration and dispatch.

class GitTools(str, Enum):
    STATUS = "git_status"
    DIFF_UNSTAGED = "git_diff_unstaged"
    DIFF_STAGED = "git_diff_staged"
    DIFF = "git_diff"
    COMMIT = "git_commit"
    ADD = "git_add"
    RESET = "git_reset"
    LOG = "git_log"
    CREATE_BRANCH = "git_create_branch"
    CHECKOUT = "git_checkout"
    SHOW = "git_show"
    INIT = "git_init"

Schema Changelog

Changes observed during successful MCP inspections.

First observedAug 15, 2025

TDQS

C2.8/5.0

Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries full burden for behavioral disclosure. While 'shows differences' implies a read-only operation, it doesn't specify output format, whether it's destructive, authentication requirements, rate limits, or error conditions. For a tool with zero annotation coverage, this leaves significant behavioral gaps.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is extremely concise - a single sentence that directly states the tool's purpose with zero wasted words. It's appropriately sized for what it communicates and is front-loaded with the essential information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool has 2 parameters with 0% schema coverage, no annotations, and no output schema, the description is inadequate. It doesn't explain parameter meanings, behavioral characteristics, or output format. For a diff tool that likely produces structured comparison data, this leaves the agent with insufficient information to use it effectively.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters2/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With 0% schema description coverage, the description provides no information about the two required parameters (repo_path and target). It doesn't explain what these parameters represent, their expected formats, or how they interact. The description fails to compensate for the complete lack of schema documentation.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose with a specific verb ('shows differences') and resource ('between branches or commits'), making it immediately understandable. However, it doesn't explicitly distinguish this tool from sibling tools like git_diff_branches, git_diff_staged, and git_diff_unstaged, which appear to offer more specific diff functionality.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no guidance on when to use this tool versus alternatives. With multiple sibling diff tools available (git_diff_branches, git_diff_staged, git_diff_unstaged), the agent receives no indication about which scenarios warrant this general 'git_diff' versus the more specific variants.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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