nf-core module meta.yml schema

JSON Schema vendored verbatim from nf-core/modules at SHA d852990. Validates every meta.yml under modules/nf-core/<tool>/<subtool>/.

Operational role. This is the IO ground truth for summarize-nextflow §4. The Mold body says “Where meta.yml exists, use it for description and IO documentation rather than parsing the script: block” — this schema is the contract that says what fields are mandatory, what shapes they take, and what type enum the LLM extracting processes[].inputs[].shape is allowed to emit.

Source-of-truth chain:

1. modules/meta-schema.json in nf-core/modules — authored alongside the module library and cited by every meta.yml via # yaml-language-server: $schema=https://raw.githubusercontent.com/nf-core/modules/master/modules/meta-schema.json.
2. Vendored verbatim into content/schemas/nf-core-module-meta.schema.json here, pinned at the SHA in upstream.
3. Re-sync: re-run curl -sL https://raw.githubusercontent.com/nf-core/modules/<sha>/modules/meta-schema.json -o content/schemas/nf-core-module-meta.schema.json and bump the SHA in this note’s upstream field.

At cast time (per docs/COMPILATION_PIPELINE.md): copied verbatim into the cast bundle’s references/schemas/. Cast skills resolving an nf-core module’s meta.yml validate against this contract before consuming the IO descriptions.

Top-level shape

The schema’s required keys are name, description, keywords (≥3, no example), authors, output, tools. Optional but commonly present: input, extra_args, topics, maintainers, containers.

The most important sub-shapes for downstream Molds:

• elementProperties.type — enum [map, file, directory, string, integer, float, boolean, list, eval]. This is the canonical set the cast skill must coerce into summary-nextflow.schema.json’s ChannelIO.shape strings.
• channelArray — list of channelElement or list-of-list (the recent flat-vs-nested change the 2025-meta.yml blog post introduced: tuple channels are nested arrays, single-element channels are flat).
• tools[] — each tool block requires description and at least one of homepage / documentation / tool_dev_url / doi. licence is an array of SPDX identifiers. identifier is a bio.tools ID (pattern ^(biotools:.*)?$).
• containers.docker / .singularity / .conda — the schema explicitly allows ^oras://.*$ for the singularity branch (legal ORAS pull form documented in component-nextflow-containers-and-envs).

Upstream license

This schema is redistributed under nf-core/modules’s MIT license. See LICENSES/nf-core-modules.LICENSE.