MCP Goose Subagents Server

Instructions

Implementation Reference

• src/index.js:280-328 (handler)

  The handler function that implements the create_goose_recipe tool. It constructs a recipe object from input args, serializes it to YAML using objectToYaml helper, writes it to a file in goose-recipes directory, and returns a success message.

  async createGooseRecipe(args) {
    const { recipe_name, role, instructions, extensions = [], parameters = {} } = args;
  
    const recipe = {
      id: recipe_name,
      version: '1.0.0',
      title: `${role.replace(/_/g, ' ').replace(/\b\w/g, l => l.toUpperCase())} Recipe`,
      description: `Specialized subagent for ${role}`,
      instructions: instructions,
      activities: [
        `Perform ${role} tasks`,
        'Analyze and provide feedback',
        'Generate deliverables'
      ],
      extensions: extensions.map(ext => ({
        type: 'builtin',
        name: ext,
        display_name: ext.replace(/_/g, ' ').replace(/\b\w/g, l => l.toUpperCase()),
        timeout: 300,
        bundled: true
      })),
      parameters: Object.entries(parameters).map(([key, value]) => ({
        key,
        input_type: typeof value,
        requirement: 'optional',
        description: `Parameter for ${key}`,
        default: value
      })),
      prompt: instructions
    };
  
    // Create recipes directory if it doesn't exist
    const recipesDir = path.join(process.cwd(), 'goose-recipes');
    await fs.mkdir(recipesDir, { recursive: true });
  
    // Write recipe file
    const recipeFile = path.join(recipesDir, `${recipe_name}.yaml`);
    const yamlContent = this.objectToYaml(recipe);
    await fs.writeFile(recipeFile, yamlContent);
  
    return {
      content: [
        {
          type: 'text',
          text: `Successfully created Goose recipe "${recipe_name}" at ${recipeFile}\n\nRecipe details:\n- Role: ${role}\n- Extensions: ${extensions.join(', ') || 'none'}\n- Parameters: ${Object.keys(parameters).join(', ') || 'none'}\n\nTo use this recipe, set GOOSE_RECIPE_PATH environment variable to the recipes directory or place the recipe in your working directory.`
        }
      ]
    };
  }

• src/index.js:87-117 (registration)

  Registration of the create_goose_recipe tool in the ListToolsRequestSchema handler, including name, description, and input schema definition.

  {
    name: 'create_goose_recipe',
    description: 'Create a reusable Goose recipe for specialized subagents',
    inputSchema: {
      type: 'object',
      properties: {
        recipe_name: {
          type: 'string',
          description: 'Name of the recipe'
        },
        role: {
          type: 'string',
          description: 'Agent role (e.g., code_reviewer, security_auditor)'
        },
        instructions: {
          type: 'string',
          description: 'Detailed instructions for the agent'
        },
        extensions: {
          type: 'array',
          items: { type: 'string' },
          description: 'List of Goose extensions to enable'
        },
        parameters: {
          type: 'object',
          description: 'Recipe parameters'
        }
      },
      required: ['recipe_name', 'role', 'instructions']
    }
  },

• src/index.js:90-116 (schema)

  Input schema definition for the create_goose_recipe tool, specifying properties and required fields.

  inputSchema: {
    type: 'object',
    properties: {
      recipe_name: {
        type: 'string',
        description: 'Name of the recipe'
      },
      role: {
        type: 'string',
        description: 'Agent role (e.g., code_reviewer, security_auditor)'
      },
      instructions: {
        type: 'string',
        description: 'Detailed instructions for the agent'
      },
      extensions: {
        type: 'array',
        items: { type: 'string' },
        description: 'List of Goose extensions to enable'
      },
      parameters: {
        type: 'object',
        description: 'Recipe parameters'
      }
    },
    required: ['recipe_name', 'role', 'instructions']
  }

• src/index.js:330-356 (helper)

  Helper function used by the handler to convert the recipe object to YAML format for file writing.

  objectToYaml(obj, indent = 0) {
    let yaml = '';
    const spaces = '  '.repeat(indent);
  
    for (const [key, value] of Object.entries(obj)) {
      if (value === null || value === undefined) continue;
  
      if (Array.isArray(value)) {
        yaml += `${spaces}${key}:\n`;
        for (const item of value) {
          if (typeof item === 'object') {
            yaml += `${spaces}- \n${this.objectToYaml(item, indent + 1).split('\n').map(line => line ? `${spaces}  ${line}` : '').join('\n')}\n`;
          } else {
            yaml += `${spaces}- ${item}\n`;
          }
        }
      } else if (typeof value === 'object') {
        yaml += `${spaces}${key}:\n${this.objectToYaml(value, indent + 1)}`;
      } else if (typeof value === 'string' && value.includes('\n')) {
        yaml += `${spaces}${key}: |\n${value.split('\n').map(line => `${spaces}  ${line}`).join('\n')}\n`;
      } else {
        yaml += `${spaces}${key}: ${value}\n`;
      }
    }
  
    return yaml;
  }