flow.yaml is the package contract for a delivery process. Schema version 1 defines metadata, compatibility, nodes, transitions, inputs, outputs, gates, and bounded rework.

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Shape

Execution starts at the first node. done is a reserved transition target, not a node type. This example uses the resolved default runner and only a whitespace check; add your project’s actual tests and required evidence before using it for delivery. The reviewer inspects a failed check before requesting rework. The current engine is 3.8.0. Keep the minimum at the earliest version that supports the Flow’s contracts. Flows that rely on rendering a consensus draft prompt with Run context before fan-out should declare engine_min: 3.8.0. Participant output is inserted as data into verifier and synthesizer prompts; template-like text in that output is not expanded again.

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Authoring rules

  • Give every node a stable unique identifier.
  • Declare all transition targets.
  • Bound every rework loop.
  • Keep runner selection explicit or inherit it intentionally.
  • Declare required inputs and evidence rather than relying on prompt prose.
  • Use setup scripts only in packages whose executable content is trusted.
  • Raise compat.engine_min only when the Flow needs the newer contract.

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Installation contract

MAIster validates the graph and compatibility before a package can run. The installed revision and trust status are recorded. Editing the package source does not mutate an already active Run.