Changelog

The format follows Keep a Changelog and the project adheres to Semantic Versioning.

[Unreleased]

Added

• Initial extraction as a standalone library.

• DAG builder with cycle detection (Baton, Baton.DAG).

• Node-backed state store (workflow_nodes) — no oban_jobs.meta mutation.

• Worker macros: Baton.Worker, Baton.LLMWorker.

• Dependency gating, completion-triggered rescheduling, retry idempotency.

• Multi-model fan-out + synthesis (Baton.MultiModel).

• Baton.Plugin (Oban plugin) for orphan rescue and failure telemetry.

• Baton.Pricing behaviour + reference implementation.

• Per-step stats and context-window capture (optional features).

• Versioned schema via Baton.Migration.

• Terminal {:workflow_finished, _} PubSub event (and [:baton, :workflow, :finished] telemetry) when a workflow's last step settles, with :completed/:failed outcome and the failed step names (Baton.Completion).

• Baton.Plugin backstops that notification for workflows that settle without a clean worker return (hard crash / Oban kill).

• Schema v2: workflow_completions table — an atomic claim guaranteeing the finished notification fires exactly once across the worker and plugin paths.

• Configurable LLM client for Baton.Debug.call_llm/3 (config :baton, llm_client: ...).

• Opt-in data retention: Baton.Plugin can prune Baton's own tables (workflow_nodes, workflow_step_stats, workflow_debug_logs, workflow_completions) once their Oban job is pruned, with an optional shorter age cap for workflow_debug_logs (prune: true, debug_log_max_age:). See Baton.Retention.

Changed

• Baton.Migration.up/down now default to the latest schema version when :version is omitted.
• Baton.MultiModel.configure/2 model injection now happens inside Baton.add/4, so the documented configure |> Baton.add usage works. Baton.MultiModel.add/4 is deprecated (now a passthrough).

Removed

• Baton.Stats.record_cache_hit (dead code — was never called).

Fixed

• Baton.LLMWorker no longer injects the Oban Pro-only :kill_timeout option, which made use Baton.LLMWorker fail to compile under Oban OSS. Replaced with a configurable timeout/1 callback (:timeout option, default :infinity).
• PubSub broadcast failures no longer crash workers — broadcasting is now best-effort over telemetry (Baton.Events).
• Baton.LLMWorker stores the step result before recording stats and no longer raises on an unexpected llm_usage key, preventing a wasted/repeated LLM call on retry.