Infracost MCP Server

Instructions

Implementation Reference

• src/cli.ts:178-217 (handler)

  Core handler function that constructs and executes the 'infracost comment' CLI command using child_process.execFile with the provided options.
  export async function executeComment(options: CommentOptions): Promise<CommandResult> { try { const args = ['comment', options.platform, '--path', resolve(options.path)]; if (options.repo) { args.push('--repo', options.repo); } if (options.pullRequest) { args.push('--pull-request', options.pullRequest); } if (options.commit) { args.push('--commit', options.commit); } if (options.tag) { args.push('--tag', options.tag); } if (options.behavior) { args.push('--behavior', options.behavior); } const { stdout, stderr } = await execFileAsync('infracost', args, { maxBuffer: 10 * 1024 * 1024, }); return { success: true, output: stdout, error: stderr || undefined, }; } catch (error) { return { success: false, error: error instanceof Error ? error.message : 'Unknown error occurred', }; } }
• src/tools.ts:52-63 (schema)

  Zod schema defining and validating the input parameters for the infracost_comment tool.
  export const CommentSchema = z.object({ path: z.string().describe('Path to Infracost JSON file'), platform: z.enum(['github', 'gitlab', 'azure-repos', 'bitbucket']).describe('Git platform'), repo: z.string().optional().describe('Repository in format owner/repo'), pullRequest: z.string().optional().describe('Pull request number'), commit: z.string().optional().describe('Commit SHA'), tag: z.string().optional().describe('Tag for comment identification'), behavior: z .enum(['update', 'new', 'delete-and-new']) .optional() .describe('Comment behavior'), });
• src/tools.ts:382-404 (handler)

  Wrapper handler in InfracostTools class that checks for infracost CLI installation, calls executeComment, and formats MCP response.
  async handleComment(args: z.infer<typeof CommentSchema>) { const isInstalled = await checkInfracostInstalled(); if (!isInstalled) { throw new Error( 'Infracost CLI is not installed. Please install it from https://www.infracost.io/docs/' ); } const result = await executeComment(args); if (!result.success) { throw new Error(result.error || 'Comment command failed'); } return { content: [ { type: 'text', text: result.output || 'Comment posted successfully', }, ], }; }
• src/index.ts:191-231 (registration)

  Tool registration in the ListTools response, defining name, description, and input schema for MCP server.
  { name: 'infracost_comment', description: 'Post cost estimate comments to pull requests on GitHub, GitLab, Azure Repos, or Bitbucket. Automatically updates existing comments. Requires infracost CLI to be installed and appropriate platform credentials.', inputSchema: { type: 'object', properties: { path: { type: 'string', description: 'Path to Infracost JSON file', }, platform: { type: 'string', enum: ['github', 'gitlab', 'azure-repos', 'bitbucket'], description: 'Git platform', }, repo: { type: 'string', description: 'Repository in format owner/repo', }, pullRequest: { type: 'string', description: 'Pull request number', }, commit: { type: 'string', description: 'Commit SHA to associate comment with', }, tag: { type: 'string', description: 'Tag for comment identification', }, behavior: { type: 'string', enum: ['update', 'new', 'delete-and-new'], description: 'How to handle existing comments (default: update)', }, }, required: ['path', 'platform'], }, },
• src/index.ts:724-727 (registration)

  Dispatch case in CallToolRequest handler that routes infracost_comment calls to tools.handleComment after schema validation.
  case 'infracost_comment': { const validatedArgs = CommentSchema.parse(args); return await tools.handleComment(validatedArgs); }