Overview

A schema is a single .mjs file that wraps a data source for AI agents. Each schema declares its tools, resources, prompts, and skills in a static main export. An optional handlers export adds response transformation.

FlowMCP v3.0.0 supports four primitives:

Tools

REST API endpoints. Map parameters to URLs, inject authentication, validate inputs. The core primitive — every schema has at least one tool. See Tools.

Resources

Local SQLite databases. Fast, deterministic queries for bulk data like company registers, transit schedules, or sanctions lists. See Resources.

Prompts

Explanatory texts that teach AI agents how a provider’s tools work together — pagination patterns, error codes, data interpretation. See Prompts.

Skills

Multi-step workflow instructions. Reusable pipelines that compose tools and resources into higher-level operations. See Skills.

Schema Structure

Every schema exports two things:

Export	Required	Purpose
main	Yes	Declarative configuration — tools, resources, prompts, skills. JSON-serializable and hashable.
handlers	No	Response transformation — pre/post processing for API responses.

Tip

Most schemas only need main. Add handlers when API responses need transformation before reaching the AI agent.