manifest.yaml Schema

A manifest.yaml file lives at the root of every capability project. It declares the capability’s public interface so the orchestrator knows how to invoke it and agents know what parameters to provide.

Schema reference

Field	Type	Required	Description
apiVersion	string	Yes	Schema version. Currently selu.io/v1.
kind	string	Yes	Must be Capability.
metadata.name	string	Yes	Unique capability identifier. Lowercase, alphanumeric, hyphens.
metadata.version	string	Yes	SemVer version (e.g. 2.1.0).
metadata.description	string	Yes	One-line description shown to agents and users.
metadata.author	string	No	Author or organization name.
metadata.tags	list	No	Searchable tags (e.g. ["search", "web"]).
spec.inputs	list	Yes	Parameters the capability accepts.
spec.inputs[].name	string	Yes	Parameter name.
spec.inputs[].type	string	Yes	Type: string, int, float, bool, object, array.
spec.inputs[].required	bool	No	Whether the parameter is required. Default false.
spec.inputs[].description	string	Yes	Description shown to the agent when selecting parameters.
spec.inputs[].default	any	No	Default value when the parameter is omitted.
spec.outputs	list	Yes	Values the capability returns.
spec.outputs[].name	string	Yes	Output field name.
spec.outputs[].type	string	Yes	Type of the output field.
spec.outputs[].description	string	Yes	Description of the output field.
spec.runtime.image	string	Yes	Docker image that implements the capability’s gRPC server.
spec.runtime.port	int	No	gRPC listen port inside the container. Default 50051.
spec.runtime.resources.cpu	string	No	CPU limit. Default 100m.
spec.runtime.resources.memory	string	No	Memory limit. Default 128Mi.
spec.runtime.env	list	No	Environment variables injected into the container.
spec.runtime.env[].name	string	Yes	Variable name.
spec.runtime.env[].value	string	No	Literal value. Mutually exclusive with secretRef.
spec.runtime.env[].secretRef	string	No	Reference to a Selu secret (e.g. selu/api-key).

Tip

The spec.inputs list is used by the orchestrator to generate the tool description sent to the LLM, so writing clear description fields directly improves how well agents use your capability.

Full example

manifest.yaml

apiVersion: selu.io/v1
kind: Capability
metadata:
  name: web-search
  version: "2.1.0"
  description: Search the web and return a list of results with titles, URLs, and snippets.
  author: selu-platform
  tags:
    - search
    - web

spec:
  inputs:
    - name: query
      type: string
      required: true
      description: The search query string.
    - name: maxResults
      type: int
      required: false
      description: Maximum number of results to return.
      default: 5

  outputs:
    - name: results
      type: array
      description: List of search result objects containing title, url, and snippet.

  runtime:
    image: ghcr.io/selu-platform/cap-web-search:2.1.0
    port: 50051
    resources:
      cpu: "200m"
      memory: "256Mi"
    env:
      - name: SEARCH_PROVIDER
        value: "duckduckgo"
      - name: SEARCH_API_KEY
        secretRef: selu/search-api-key

Validation

Run selu capability validate to check your manifest against the schema. The CLI verifies that all required fields are present, types are valid, and secret references resolve to existing Selu secrets.