MCP Server - A Node In Layers Package for building MCP Servers

What is MCP Server - A Node In Layers Package for building MCP Servers?

A Node In Layers package for building MCP servers that exposes domains, features, and model CRUDs as MCP tools so an AI can discover and call them. It is self-describing, automatically organizes tools into an optimized system, and includes built-in prompting and examples to improve AI tool selection and formatting accuracy.

How to use MCP Server - A Node In Layers Package for building MCP Servers?

Install with npm install @node-in-layers/mcp-server. Configure in /config.base.mts by adding the MCP server module to the apps list, including the mcp layer in the layer order, and setting server connection details. Run the server via a script that calls system.mcp[McpNamespace].start(context).

Key features of MCP Server - A Node In Layers Package for building MCP Servers

• Automatically exposes features and model CRUDs as MCP tools.
• Self-describing system with a configurable START_HERE navigation tool.
• Domain-organized tool surface with list_domains, list_features, describe_feature, execute_feature, and model CRUD tools.
• Flat mode to expose feature functions as individual tools without navigation tools.
• Component hiding via hideComponents to restrict visibility of domains, features, or models.
• Custom tool extension using addTool() and addAnnotatedFunction().

Use cases of MCP Server - A Node In Layers Package for building MCP Servers

• Build an MCP server that exposes a business domain’s features and data models to an AI assistant.
• Create a self-documenting API surface where the AI can discover and execute operations without hardcoded tool names.
• Reduce tool selection errors in systems with hundreds of tools through automatic organization and prompting.
• Expose a minimal tool surface (flat mode) for systems with a single function or small tool set.
• Hide sensitive or experimental domains/features while keeping the rest of the system available.

FAQ from MCP Server - A Node In Layers Package for building MCP Servers

What is the difference between normal mode and flat mode?

In normal mode the server exposes domain-, feature-, and model-level navigation tools (START_HERE, list_domains, etc.). In flat mode each feature function becomes its own MCP tool named domain_featureName, and navigation tools are not exposed.

How do I hide certain domains, features, or model CRUDs?

Configure hideComponents in the MCP namespace with domains (hide entire domains), paths (dot-separated paths to specific features or models), or allModels (hide all model CRUD tools).

What is the START_HERE tool and how is it configured?

START_HERE is the first tool an AI should call to learn how to navigate the system. Its response includes system metadata, default system entries, and optionally pre‑fetched domain/feature lists. You can also add custom examplesOfUse to document higher‑level flows.

How do I add custom tools beyond the auto‑exposed ones?

Use the addTool() method on the MCP layer (accessible via mcp[McpNamespace] inside a layer that runs after the MCP layer). Provide a name, description, input/output schema, and an execute function.

What are the runtime requirements?

The package requires Node.js, npm, TypeScript, and the @node-in-layers/core library. It is used within a Node In Layers system configuration.