Infracost MCP Server

Instructions

Implementation Reference

• src/cli.ts:112-155 (handler)

  Core handler function that executes the 'infracost output' CLI command with the provided options, handles output parsing for JSON, and returns success/error with stdout/stderr.

  export async function executeOutput(options: OutputOptions): Promise<CommandResult> {
    try {
      const args = ['output', '--path', resolve(options.path)];
  
      if (options.format) {
        args.push('--format', options.format);
      }
  
      if (options.outFile) {
        args.push('--out-file', resolve(options.outFile));
      }
  
      if (options.fields && options.fields.length > 0) {
        args.push('--fields', options.fields.join(','));
      }
  
      if (options.showSkipped) {
        args.push('--show-skipped');
      }
  
      const { stdout, stderr } = await execFileAsync('infracost', args, {
        maxBuffer: 10 * 1024 * 1024,
      });
  
      let parsedData;
      if (options.format === 'json' && !options.outFile && stdout.trim()) {
        try {
          parsedData = JSON.parse(stdout);
        } catch (e) {}
      }
  
      return {
        success: true,
        output: options.outFile ? `Output saved to ${options.outFile}` : stdout,
        error: stderr || undefined,
        data: parsedData,
      };
    } catch (error) {
      return {
        success: false,
        error: error instanceof Error ? error.message : 'Unknown error occurred',
      };
    }
  }

• src/tools.ts:334-356 (handler)

  MCP tool handler method in InfracostTools class. Checks if infracost CLI is installed, calls executeOutput, and formats the response as MCP content.

  async handleOutput(args: z.infer<typeof OutputSchema>) {
    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 executeOutput(args);
  
    if (!result.success) {
      throw new Error(result.error || 'Output command failed');
    }
  
    return {
      content: [
        {
          type: 'text',
          text: result.output || 'Output generated successfully',
        },
      ],
    };
  }

• src/tools.ts:28-46 (schema)

  Zod schema for validating input arguments to the infracost_output tool.

  export const OutputSchema = z.object({
    path: z.string().describe('Path to Infracost JSON file(s)'),
    format: z
      .enum([
        'json',
        'table',
        'html',
        'diff',
        'github-comment',
        'gitlab-comment',
        'azure-repos-comment',
        'bitbucket-comment',
      ])
      .optional()
      .describe('Output format'),
    outFile: z.string().optional().describe('Save output to file'),
    fields: z.array(z.string()).optional().describe('Fields to include in output'),
    showSkipped: z.boolean().optional().describe('Show skipped resources'),
  });

• src/index.ts:714-717 (registration)

  Switch case in CallToolRequestHandler that routes 'infracost_output' calls to tools.handleOutput after schema validation.

  case 'infracost_output': {
    const validatedArgs = OutputSchema.parse(args);
    return await tools.handleOutput(validatedArgs);
  }

• src/index.ts:134-175 (registration)

  Tool registration in ListToolsRequestHandler, including name, description, and input schema mirroring OutputSchema.

  {
    name: 'infracost_output',
    description:
      'Combine and format Infracost JSON files. Useful for merging multiple cost estimates or converting formats. Requires infracost CLI to be installed.',
    inputSchema: {
      type: 'object',
      properties: {
        path: {
          type: 'string',
          description: 'Path to Infracost JSON file(s) - supports glob patterns',
        },
        format: {
          type: 'string',
          enum: [
            'json',
            'table',
            'html',
            'diff',
            'github-comment',
            'gitlab-comment',
            'azure-repos-comment',
            'bitbucket-comment',
          ],
          description: 'Output format',
        },
        outFile: {
          type: 'string',
          description: 'Save output to a file',
        },
        fields: {
          type: 'array',
          items: { type: 'string' },
          description: 'Fields to include in output (e.g., ["price", "monthlyQuantity"])',
        },
        showSkipped: {
          type: 'boolean',
          description: 'Show skipped resources in output',
        },
      },
      required: ['path'],
    },
  },