Conditional Skipping

The skip_if field on a step definition evaluates a condition against a parent step’s output, skipping the step entirely when the condition is true.

ParentCond

The ParentCond struct defines the skip condition:

Field	JSON Key	Type	Description
StepID	`step_id`	`string`	Parent step to evaluate (must be in `depends_on`)
Field	`field`	`string`	Top-level key in the parent’s JSON output
Op	`op`	`string`	Comparison operator
Value	`value`	`any`	Value to compare against

Supported Operators

Operator	Meaning
`==`	Equal
`!=`	Not equal
`<`	Less than
`>`	Greater than
`<=`	Less than or equal
`>=`	Greater than or equal

Type Coercion

The condition evaluator compares values using these rules:

Numbers: Both sides parsed as float64 (JSON default). All six operators supported.
Strings: Lexicographic comparison. All six operators supported.
Booleans: Only == and != are supported. Other operators return false.
Mismatched types: Condition evaluates to false (step runs normally).

If the parent step has no output or the field is missing, the condition evaluates to false and the step executes.

Builder API

Use SkipIf with a StepRef for compile-time-safe references:

wf := dag.NewWorkflow("review-pipeline")

lint := wf.Task("lint", "lint.run").
    WithTimeout(5 * time.Minute)

postResults := wf.Task("post-results", "github.comment").
    After(lint).
    WithTimeout(30 * time.Second).
    SkipIf(lint, "issues_found", "==", 0)

If the lint step’s output contains {"issues_found": 0}, post-results is skipped. The SkipIfOutput helper constructs the ParentCond internally.

JSON Schema

{
  "id": "post-results",
  "task": "github.comment",
  "timeout": "30s",
  "type": "normal",
  "depends_on": ["lint"],
  "skip_if": {
    "step_id": "lint",
    "field": "issues_found",
    "op": "==",
    "value": 0
  }
}

Skip Semantics

When a step is skipped:

Its status is set to skipped
Downstream steps treat skipped as completed. A step waiting on a skipped dependency proceeds normally. The skipped step produces no output, so any downstream skip_if referencing its fields evaluates to false.
Skipped steps do not count against concurrency limits.
Skipped steps do not appear in the dead letter queue.

Validation

The workflow validator enforces:

skip_if.step_id must reference a step in the depends_on list (not any arbitrary step)
skip_if.op must be one of the six valid operators
The referenced step must exist in the workflow

Violations produce a clear error from Build() or Validate().

Normal Steps – the default step type that supports skip_if
Error Handling – what happens when non-skipped steps fail
Priority – ordering runs when steps are skipped

Rate Limiting Priority