Helm Values Schema

/helm-values-schema [chart]

Use this skill when the user asks to add, change, review, or regenerate a Helm chart values.schema.json, or when a chart feature changes values.yaml in a chart that uses schema annotations.

Detection

A chart uses helm-values-schema-json if charts/<chart>/values.yaml contains either:

• # @schema comments
• a top-level schema reference such as # $schema: ./values.schema.json

When a chart uses this flow, changes to values.yaml must keep schema annotations and values.schema.json in sync.

Documentation

Prefer Context7 for current helm-values-schema-json docs when available.

Upstream documentation:

https://github.com/losisin/helm-values-schema-json/blob/main/docs/README.md

Compatibility

Helm validates chart values with JSON Schema draft-07. Keep generated schemas compatible with draft-07 even if external schema tooling supports newer drafts.

Workflow

1. Read charts/<chart>/values.yaml.
2. Check whether # @schema annotations or # $schema: ./values.schema.json are present.
3. If changing or adding values, preserve nearby annotations and add annotations when inferred schema would be wrong or too loose.
4. Preserve helm-docs comments. When a field has both # @schema and helm-docs # -- comments, # @schema comments must be above the helm-docs description comments.
5. Regenerate values.schema.json.
6. Review the schema diff for only intentional changes.
7. Ensure values changes also have helm-unittest coverage for rendered behavior where applicable.

helm-docs Integration

helm-values-schema-json supports using descriptions from helm-docs comments since v2.0.0, but only when enabled with --use-helm-docs.

Example:

helm schema --use-helm-docs

# -- My description
fullnameOverride: bar

Generates:

{
  "fullnameOverride": {
    "description": "My description",
    "type": "string"
  }
}

Unsupported helm-docs Features

The schema plugin does not support helm-docs-specific properties such as:

• # @default --
• # @section --

It also does not support detached helm-docs comments. Comments must be directly above the property or inline in a supported form.

Supported:

# fullnameOverride -- This works
fullnameOverride: bar

Not supported by the schema plugin:

fullnameOverride: bar

# fullnameOverride -- This does not work for schema generation.
fullnameOverride: bar

Helm-docs itself does not understand # @schema comments. When both # @schema and helm-docs comments are above a field, put # @schema first so schema annotations are not included in the generated description. Treat the inverse order as invalid: helm-docs will include the schema annotation text in the description.

Good:

# @schema maxLength:10
# -- My awesome nameOverride description
nameOverride: "myapp"

Bad:

# -- My awesome nameOverride description
# @schema maxLength:10
nameOverride: "myapp"

Annotation Placement

# @schema annotations may be placed inline, on the line above a field, or in specific cases below a block. Preserve the surrounding style already used in the chart, except when the existing style conflicts with helm-docs ordering. If a value has a helm-docs # -- description, any standalone # @schema comments for that value must be above the # -- comment, never between the helm-docs comment and the value.

Examples:

fullnameOverride: "myapp" # @schema maxLength:10;pattern:^[a-z]+$

# @schema maxLength:10;pattern:^[a-z]+$
nameOverride: "myapp"

# @schema maxLength:10
# -- My awesome nameOverride description
nameOverride: "myapp"

# Invalid with helm-docs: the schema annotation becomes part of the description.
# -- My awesome nameOverride description
# @schema maxLength:10
nameOverride: "myapp"

resources:
  limits: {}
  requests: {}
# @schema additionalProperties:false

Multiple schema annotations can be separated with semicolons.

Commands

For Loki, use the repository target:

make helm-schema HELM_CHART=loki

The underlying command currently runs:

helm schema --config .github/linters/.schema.yaml -f charts/loki/values.yaml -o charts/loki/values.schema.json

If adding schema generation for another chart, follow the chart's local Makefile or CI pattern instead of inventing a one-off command.

Rules

• Do not hand-edit values.schema.json when it can be regenerated.
• Do not remove existing # @schema annotations unless the associated value is removed.
• Keep schema annotations as close as possible to the value they describe.
• Keep # @schema comments above helm-docs # -- comments. Never add a standalone # @schema comment below a helm-docs description comment for the same value.
• Include regenerated values.schema.json in the change.
• Values changes that affect rendered manifests should also be covered by helm-unittest tests.