Extension Catalog and Wizard

The extension catalog is the data source behind the wizard’s extension-pack flow. It maps user-facing extension types to the canonical manifest entries Greentic understands.

Use it through gtc wizard; do not hand-author catalog internals unless you are maintaining Greentic tooling.

Wizard Entry Points

Interactive authoring:

gtc wizard

Agentic and CI authoring:

gtc wizard --schema
gtc wizard --answers extension-pack-answers.json

The launcher schema includes the embedded pack and bundle answer schemas. Coding agents should fetch this schema first, generate an answers file that matches it, and replay the wizard non-interactively.

What the Catalog Provides

Each extension type can define:

a stable type id such as messaging, events, secrets, or deployer
the canonical manifest key to write
localized names and descriptions
questions for the wizard
templates for scaffolded files
plan steps such as creating directories, writing files, delegating component or flow creation, and running CLI commands

The wizard writes generated extension answers as JSON under extensions/ and merges the validated extension payload into pack.yaml.

Catalog Types

The current catalog covers:

messaging
events
oauth
mcp
state
telemetry
secrets
admin
control
observer
deployer
runtime-capability
contract
ops
capability-offer
custom-scaffold

Most types map to greentic.ext.capabilities.v1. The deployer type maps to greentic.deployer.v1.

Default and Custom Catalogs

The wizard can use the bundled catalog, check a catalog source, or use an explicit catalog reference when that is supported by the answer schema. Catalog references may be local files, fixtures, or registry-backed sources depending on the CLI build.

For normal extension authoring, prefer the bundled/default catalog exposed by gtc wizard. For automation, pin the answers file and validate it with the schema before applying it.

Legacy Note

This page replaces the old “designer extensions” documentation. .gtxpack, gtdx, and design-time extension classes are not the current extension-pack authoring path.