Generate and Validate EAS CI/CD Workflows

EAS Workflows Skill helps developers write and edit EAS CI/CD workflow YAML files for Expo projects, backed by the current schema rather than memorized syntax that can drift out of date. Before generating or validating a workflow, it fetches three reference resources via a caching Node.js fetch script (node {baseDir}/scripts/fetch.js <url>, which caches responses using ETags): the JSON Schema at https://api.expo.dev/v2/workflows/schema (the source of truth for validation, job types and their required/optional parameters, trigger types, and runner/VM-image enums), the syntax documentation at expo's GitHub docs (overview of workflow YAML syntax, examples, expression syntax and contexts), and the pre-packaged jobs documentation (supported job types, their parameters and outputs).

Workflow files live in .eas/workflows/*.yml (or .yaml) with five top-level keys: name (display name), on (triggers, at least one required), jobs (job definitions, required), defaults (shared defaults for all jobs), and concurrency (control over parallel workflow runs) - the schema is the authority for the full specification of each section. Dynamic values use ${{ }} expression syntax across defined contexts: github.* for repository and event information, inputs.* for workflow_dispatch input values, needs.* for outputs and status from dependent jobs, jobs.* as an alternative job-output syntax, steps.* for step outputs within custom jobs, and workflow.* for workflow metadata.

When generating or editing a workflow, the skill fetches the schema for current job types, parameters, and allowed values, validates that required fields are present for each job type, verifies that job references in needs and after actually exist in the workflow, checks that expressions reference valid contexts and outputs, and ensures if conditions respect the schema's length constraints. After generating or editing, it runs the validator (installing script dependencies if missing, then node {baseDir}/scripts/validate.js <workflow.yml> [...]), which fetches the latest schema and checks the YAML structure - any reported errors are fixed before the workflow is considered complete. When a user asks about available options (job types, triggers, runner types), the skill fetches the schema and derives the answer from it rather than relying on potentially outdated knowledge.

Use this skill when creating, editing, or validating .eas/workflows/*.yml files for an Expo project, for tasks involving EAS build pipelines, deployment automation, workflow triggers, or Expo CI/CD configuration, or when schema-backed workflow guidance is needed instead of stale memorized syntax. Do not treat the output as a substitute for environment-specific validation, testing, or expert review, and stop to ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.

Expo developers setting up or maintaining EAS build and deployment CI/CD pipelines who need workflow YAML validated against the current schema rather than guessed from memory.