import { z } from "zod";
import { FastMCP } from "fastmcp";
import { AppConfig } from "../../models/appConfig.js";
import { ExtendedLogger } from "../../helpers/logger.js";
import { createGitInstance, validateGitRepository, GitOperationResult } from "./common.js";
export const ToolName: string = `git_diff`;
/**
* Gets the diff between two commits in a git repository
* @param workingDir Directory of the git repository
* @param fromCommit First commit hash to compare from
* @param toCommit Second commit hash to compare to
* @param options Optional diff options (files, unified, ignoreSpace)
* @param logger Logger instance for operation tracking
*/
async function executeGitDiff(
workingDir: string,
fromCommit: string,
toCommit: string,
options: {
files?: string[];
unified?: number;
ignoreSpace?: boolean;
ignoreBlankLines?: boolean;
} = {},
logger: ExtendedLogger
): Promise<GitOperationResult> {
try {
// Validate repository
await validateGitRepository(workingDir, logger);
const git = createGitInstance(workingDir);
// Build diff options
const diffOptions: string[] = [fromCommit, toCommit];
if (options.unified !== undefined) {
diffOptions.unshift(`-U${options.unified}`);
}
if (options.ignoreSpace) {
diffOptions.unshift('--ignore-space-change');
}
if (options.ignoreBlankLines) {
diffOptions.unshift('--ignore-blank-lines');
}
if (options.files && options.files.length > 0) {
diffOptions.push('--');
diffOptions.push(...options.files);
logger.info(`Getting diff for specific files: ${options.files.join(', ')}`);
}
// Get the diff
logger.info(`Getting diff between commits: ${fromCommit} and ${toCommit}`);
const diffResult = await git.diff(diffOptions);
const successMessage = `Successfully retrieved diff between ${fromCommit} and ${toCommit}`;
logger.info(successMessage);
return {
success: true,
message: diffResult || 'No differences found'
};
} catch (error) {
const errorMessage = `Failed to get diff: ${error}`;
logger.error(errorMessage);
return {
success: false,
message: errorMessage,
error: String(error)
};
}
}
/**
* Adds the git diff tool to the MCP server.
*/
export function Add_Tool(server: FastMCP, config: AppConfig, logger: ExtendedLogger): void {
// Check if tool is allowed
if (!config.validateTool(ToolName))
return;
// Schema for input parameters
const ClientArgsSchema = z.object({
workingDir: z.string()
.describe("Directory of the git repository to analyze"),
fromCommit: z.string()
.describe("Initial commit hash to compare from"),
toCommit: z.string()
.describe("Target commit hash to compare to"),
files: z.array(z.string())
.optional()
.describe("Optional list of specific files to check for differences"),
unified: z.number()
.min(0)
.optional()
.describe("Number of context lines around the differences (translates to -U option in git diff command)"),
ignoreSpace: z.boolean()
.optional()
.default(true)
.describe("Whether to ignore whitespace changes in the diff (--ignore-space-change)"),
ignoreBlankLines: z.boolean()
.optional()
.default(true)
.describe("Whether to ignore changes that are empty lines only (--ignore-blank-lines)")
});
// Add tool to server
server.addTool({
name: ToolName,
description: "Returns the diff between two commits in a git repository. " +
"Supports filtering by specific files, setting context lines (unified), " +
"and ignoring whitespace or blank line changes. " +
"Only works within allowed directories.",
parameters: ClientArgsSchema,
execute: async (args, context) => {
return logger.withOperationContext(async () => {
logger.info(`Calling tool '${ToolName}':`, args);
try {
// Validate and resolve working directory
const workingDir = config.validatePath(args.workingDir);
// Execute git diff
const result = await executeGitDiff(
workingDir,
args.fromCommit,
args.toCommit,
{
files: args.files,
unified: args.unified,
ignoreSpace: args.ignoreSpace,
ignoreBlankLines: args.ignoreBlankLines
},
logger
);
return result.success
? result.message
: `Error: ${result.message}`;
} catch (error) {
logger.error(`${ToolName} failed:`, error);
throw error;
}
});
},
});
}
