GitHub Enterprise MCP Server

Instructions

Implementation Reference

• src/tools/repository.ts:187-239 (handler)

  The core handler function that executes the create-branch tool. Validates inputs using CreateBranchSchema, checks if the branch exists, determines the source branch, fetches its SHA, and creates the new branch ref via GitHub API.

  export async function createBranch(args: unknown): Promise<any> {
    const { owner, repo, branch, from_branch } = CreateBranchSchema.parse(args);
    const github = getGitHubApi();
  
    return tryCatchAsync(async () => {
      // Check if branch already exists
      try {
        await github.getOctokit().git.getRef({
          owner,
          repo,
          ref: `heads/${branch}`,
        });
        
        return {
          success: false,
          message: `Branch '${branch}' already exists in ${owner}/${repo}`,
        };
      } catch (error: any) {
        // If error is not 404 (not found), rethrow it
        if (error.status !== 404) {
          throw error;
        }
      }
  
      // Get the SHA of the latest commit on the source branch
      const sourceBranch = from_branch || await github.getDefaultBranch(owner, repo);
      const { data: refData } = await github.getOctokit().git.getRef({
        owner,
        repo,
        ref: `heads/${sourceBranch}`,
      });
  
      // Create a new branch from the source branch
      const { data } = await github.getOctokit().git.createRef({
        owner,
        repo,
        ref: `refs/heads/${branch}`,
        sha: refData.object.sha,
      });
  
      return {
        success: true,
        ref: data.ref,
        url: data.url,
        object: {
          sha: data.object.sha,
          type: data.object.type,
          url: data.object.url,
        },
        message: `Branch '${branch}' created from '${sourceBranch}' in ${owner}/${repo}`,
      };
    }, 'Failed to create branch');
  }

• src/utils/validation.ts:71-74 (schema)

  Zod validation schema used in the handler to parse and validate the input arguments for create-branch.

  export const CreateBranchSchema = OwnerRepoSchema.extend({
    branch: z.string().min(1, 'Branch name is required'),
    from_branch: z.string().optional(),
  });

• src/server.ts:1175-1177 (registration)

  Switch case in the MCP tool call handler that routes 'create-branch' invocations to the createBranch function.

  case 'create-branch':
    result = await createBranch(parsedArgs);
    break;

• src/server.ts:222-248 (schema)

  Input schema definition for the create-branch tool in the MCP server's listTools response.

  {
    name: 'create-branch',
    description: 'Create a new branch in a GitHub repository',
    inputSchema: {
      type: 'object',
      properties: {
        owner: {
          type: 'string',
          description: 'Repository owner',
        },
        repo: {
          type: 'string',
          description: 'Repository name',
        },
        branch: {
          type: 'string',
          description: 'Name for the new branch',
        },
        from_branch: {
          type: 'string',
          description: 'Source branch to create from (defaults to the repository\'s default branch)',
        },
      },
      required: ['owner', 'repo', 'branch'],
      additionalProperties: false,
    },
  },