AWL reference — Ablative docs

Document structure

A file’s opening declaration selects a workflow, worker, workloop or binding family. A workflow declares a name, typed inputs and terminal outcomes. Its narration goes immediately before the opening line.

workflow awl 1

Opens the document: one `.awl` file declares exactly one workflow, named here.

form declaration
positions top-level

//! Greet whoever starts the run.
workflow greet_visitor
  input name: String
  outcome done: type String, route success

step greet
  "hello " + name -> greeting
  route done(greeting)

input awl 3

Declares one field of the workflow's start contract; it is repeatable.

form header-clause
positions workflow-header, workloop-header

//! Each `input` line declares one field of the start contract.
workflow open_ticket
  input title: String
  input urgent: Bool
  outcome done: type String, route success

step file
  outcome fast: if urgent, route done("expedited: " + title)
  outcome slow: else, route done("queued: " + title)

signal awl 3

Declares a durable signal this workflow receives; a step body takes delivery with `wait`.

form header-clause
positions workflow-header, workloop-header

//! Hold until the declared approval signal arrives.
workflow release_gate
  input build_id: String
  signal approval: Approval
  outcome done: type String, route success

type Approval { reviewer: String }

step hold
  wait approval -> decision
  route done(decision.reviewer + " approved " + build_id)

failure awl 3

Maps a declared outcome to the engine's failed status, and after `on` names a step's compensation block.

form statement
positions workflow-header, step-body, route-target, step-reference

//! `route failure` marks the outcome that fails the run.
workflow validate_order
  input order_id: String
  input valid: Bool
  outcome accepted: type String, route success
  outcome rejected: type String, route failure

step validate
  outcome ok: if valid, route accepted(order_id)
  outcome bad: else, route rejected("invalid order: " + order_id)

success awl 3

Maps a declared outcome to the engine's completed status.

form header-clause
positions workflow-header, route-target, step-reference

//! `route success` maps the outcome to the engine's completed status.
workflow finish_job
  input job: String
  outcome done: type String, route success

step wrap
  route done("finished " + job)

level awl 3

Marks where an `input` or an `outcome` is set — `level board` once when the workflow is connected, `level card` on every card; a declaration with no clause is unmarked and is never defaulted.

form header-clause
positions workflow-header, workloop-header

//! `level` says WHERE a fact is set: once for the board, or on every card.
workflow triage_card
  input board_name: String, level board
  input card_title: String, level card
  outcome triaged: type Triage, route success, level card

type Triage { priority: String }

step triage
  route triaged(priority: board_name + "/" + card_title)

board awl 3

The level of a fact set ONCE, when the workflow is connected to a board, and the same for every run it starts.

form header-clause
positions workflow-header, workloop-header

//! `level board` marks a fact set ONCE, when the workflow is connected.
workflow notify_board
  input channel: String, level board
  input card_title: String, level card
  outcome notified: type Notice, route success, level card

type Notice { sent_to: String }

step notify
  route notified(sent_to: channel + ": " + card_title)

card awl 3

The level of a fact carried by every card: read when the card fires the workflow, written back when the run ends.

form header-clause
positions workflow-header, workloop-header

//! `level card` marks a fact every card carries, read when it fires.
workflow score_card
  input card_title: String, level card
  outcome scored: type Score, route success, level card

type Score { title: String, points: Int }

step score
  route scored(title: card_title, points: 1)

Use two-space indentation and lowercase names with underscores. Type names and enum alternatives use TitleCase. The formatter writes one canonical rendering.

An outcome is the workflow’s terminal value. Successful record outcomes also supply the named card output fields. Scalar, list and enum outcomes return their value directly.

The board and card level clauses mark where an input or outcome belongs. Omission stays unmarked. There is no output keyword.

Find a construct

Types and values

Records, enums, optional fields, schema imports, constants and expressions.

Workers and placement

Actions, retries, declared bodies, agent harnesses and relative nodes.

Steps and decisions

Dependencies, guards, routes and list pipelines.

Parallel work and loops

Fork/join, regions, collection and bounded iteration.

Children, waits and failure

Subflows, child results, sleeps, signal waits and failure handlers.

Signals and queries

Sending, receiving and registering read-only answers.

Commands

Headers, arguments, capture forms, working directories and exports.

Recipes

Typed parameters, walls, artifacts, preconditions and firing receipts.

Workloops

Cadence, carried state, health, detached work and retirement.

Roles and bindings

Separate a flow's contract from a venue's queue and harness facts.

Compiler boundaries

Failure handlers: No substeps, per-item regions, bounded loops, forks, timed waits or child spawns in on failure. Untimed wait is supported.
Forks: A collection fork body is exactly one unbound action or child call. Each named branch is one action call.
Substeps: Only a step body’s trailing substep block compiles. No after or max visits clause on a substep.
Indexing: Literal indexing is refused in parallel fork branches, parallel per-item tracks, outcome guards and visit bounds. Sequential tracks accept indexing.
Sort: The sort key must be Int, Float or String.
Schema values: schema of Type compiles in constant position. Bind a const and use it later.
Routes: A route to the middle of a folded fall-through chain is refused.
Check scope: awl check parses and typechecks. Use awl emit --target beam with an output file to verify bytecode compilation locally before deployment.

Compile the document before deploying it. Worker activities also require the declared programs or agent harness on their execution hosts.

Local guide

The installed command also serves this vocabulary as text or JSON, with a complete example for each word. See the guide command.

Editor support

Use the AWL language server and editor setup for diagnostics, formatting, completion and navigation.