Quick start

Build a small schema without creating an engine, opening a database, or running migrations.

Define two models

Save the following as models.py in a scratch directory:

from sqlalchemy import ForeignKey, String
from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column, relationship

class Base(DeclarativeBase):
    pass

class User(Base):
    __tablename__ = "users"
    id: Mapped[int] = mapped_column(primary_key=True)
    name: Mapped[str] = mapped_column(String(100))
    tasks: Mapped[list["Task"]] = relationship(back_populates="owner")

class Task(Base):
    __tablename__ = "tasks"
    id: Mapped[int] = mapped_column(primary_key=True)
    owner_id: Mapped[int] = mapped_column(ForeignKey("users.id"), index=True)
    owner: Mapped[User] = relationship(back_populates="tasks")

Build a document

Run in that scratch directory, using the environment where you installed the package:

laranex-schema-viewer build

With no options, build finds the single models.py or models package in the current directory and writes schema-viewer.json, a laranex-schema 2.0 document. The output reports actual table, model, ORM relationship, and diagnostic counts. This example declares two tables, two models, one physical FK, and two ORM relationships.

Open the viewer

laranex-schema-viewer serve

Open http://127.0.0.1:8765. Select a table for details, search for owner_id, and toggle the foreign-key and ORM layers independently.

Connect an agent

laranex-schema-viewer mcp --snapshot /absolute/path/to/schema-viewer.json

This command speaks MCP over stdio, so configure it as a client subprocess rather than opening it in a browser. See MCP integration.