The Amadeus platform introduces a core operational efficiency feature for the LC Settlement Stack: Cost-Aware Routing. Any execution step can be seamlessly reassigned to a cheaper automation executor without touching or redeploying the core application state machine.

The Executor Abstraction

transaction_tracker/src/orchestrator/executors/base.ts defines a uniform contract for three primary kinds of automated executors:

Executor Kind	Cost Unit (Relative)	Execution Mode	Example Use Case
llm	~3	Synchronous (In-Process)	Qwen VL document examination
pad	~10	Asynchronous (Fire-and-Track)	Power Automate Desktop flow
uipath	~100	Asynchronous (Fire-and-Track)	UiPath Orchestrator job

An executor's run(ctx) function is guaranteed to return one of three deterministic outcomes:

• completed — The engine advances the state machine immediately (Typically for LLM or instant API executors).
• dispatched — A job was successfully handed to an external asynchronous robot. The state machine pauses and will not advance until that robot reports back via a complete_step REST call or an A2A task.complete message.
• failed — The execution failed immediately, returning a detailed reason string.

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The Routing Engine

The router (executors/router.ts) utilizes a strict evaluation matrix in chooseExecutor(step, type):

1. Capability Matching: Identifies all registered executors whose capabilities match the requested (step, type).
2. Preference Override: Checks if an explicit EXECUTOR_PREFERENCES environment variable exists for this step. If found, it forces the selection.
3. Cost Optimization: If no explicit override exists, it automatically selects the executor with the lowest costUnit.
4. Tiebreaker: Falls back to the order of registration.

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Default Wiring (executorMap.ts)

Step	Assigned Executor	Kind	Cost
submitted	(None — manual/Contact Point)	—	0
distributed_to_analyst	executor.pad.distribute	pad	10
doc_examined	executor.qwen_vl.doc_exam	llm	3
ee_ntf_created	executor.pad.ee_create	pad	10
ee_ntf_approved	(None — manual/checker)	—	0
mt_converted	executor.uipath.mt_convert	uipath	100
swift_released	executor.uipath.swift_release	uipath	100
settled	executor.uipath.settle	uipath	100
advised	executor.pad.advise	pad	10

ROI Impact: Utilizing this dynamic map brings the total base cost per LC down to ~333 units, compared to ~900 units if every step ran exclusively on premium UiPath robots—a 63% reduction achieved with zero structural code changes.

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Re-Routing Steps Dynamically

To re-route a step to a cheaper executor, no code modification is required. Simply set the environment variable and restart the transaction_tracker:

bash
export EXECUTOR_PREFERENCES="mt_converted=executor.pad.mt_convert"

The moment a PAD-based alternative executor is registered for mt_converted, this environment variable instantly forces the router to utilize it over UiPath, immediately reducing execution costs.