The tox schema command generated a JSON Schema that was missing several type mappings, packaging-related keys, and lacked IDE-friendly metadata. With no_package = true, keys like package, skip_install, use_develop, package_env, and package_root were absent from the generated schema. The int and PythonConstraints types were logged as unrecognized, and editors using taplo/Even Better TOML had no documentation links.

This generates a complete schema by using a packaging-enabled config for introspection, ensuring all configuration keys are present regardless of the project's packaging mode. It adds x-taplo metadata with links to tox documentation for all major sections, proper handling of int and PythonConstraints types, product dict support for env_list, and marks legacy aliases (usedevelop, setenv, basepython, etc.) as "deprecated": true with descriptions recommending the canonical names. The $schema URI is corrected for draft-07 compliance, $id points to the canonical raw GitHub URL, and schema introspection uses any available environment instead of hardcoding "py". A freshness test ensures the committed tox.schema.json stays in sync with the generator output.

A new update-schemastore.yaml workflow automatically opens a PR on SchemaStore to sync the local copy of tox.json whenever a new release tag is pushed. It copies the committed tox.schema.json (kept fresh by the test), adjusts the $id for SchemaStore resolution, and creates the PR via gh. Requires a SCHEMASTORE_TOKEN secret with fork/PR permissions on the SchemaStore repo.

Companion PR at SchemaStore/schemastore#5402 adds tox.toml to the SchemaStore catalog and updates partial-tox.json to provide full autocompletion for [tool.tox] in pyproject.toml.

Fixes #1388