CircleCI Reusable Command "required parameter" - Fix Params

By Kaveh Alemi·Latchkey

A reusable command or executor was invoked without a required parameter, or its steps reference a parameter that was never declared. Parameterized commands only resolve when every << parameters.* >> is declared and every required value is supplied.

What this error means

Validation fails naming a missing required parameter or an undeclared one. The command cannot be expanded into steps because a parameter reference has no value or no declaration.

Config is invalid:
  - command 'deploy': required parameter 'environment' not provided
  - command 'deploy': parameter 'reigon' is not declared

Common causes

Required parameter omitted at the call site

A parameter without a default: is required. Invoking the command without it fails validation.

Step references an undeclared parameter

Using << parameters.region >> inside the command’s steps requires a matching parameters: entry. A typo (reigon) has no declaration.

Wrong parameter type

Passing a string where the parameter declares type: integer or type: boolean, or a value outside an enum, is rejected.

How to fix it

Declare parameters and pass required ones

commands:
  deploy:
    parameters:
      environment:
        type: enum
        enum: [staging, production]
      region:
        type: string
        default: us-east-1
    steps:
      - run: ./deploy.sh --env << parameters.environment >> --region << parameters.region >>

jobs:
  release:
    docker: [{ image: cimg/base:current }]
    steps:
      - checkout
      - deploy:
          environment: production

Give optional parameters defaults

1. Add a default: to any parameter the caller may omit.
2. Reference only declared parameters in the command’s steps.
3. Match the passed value to the declared type/enum.

How to prevent it

• Declare every parameter a command/executor references in its steps.
• Give optional parameters defaults so callers can omit them.
• Validate config so missing/mistyped parameters fail on the PR.

Frequently asked questions

Related guides

References

• GitHub Actions documentation