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Use case · Schema transformation

Payment Schema Mapping (SWIFT MT ↔ ISO 20022)

Banks hold decades of transformation logic that converts legacy SWIFT MT messages into ISO 20022 XML and internal wrappers, but the mapping rules are largely undocumented and locked in existing systems. This reverse-engineers the field-level rules from real message pairs rather than hand-authoring them.

SWIFT MTISO 20022 (pacs · camt · fxtr)Deterministic parserConfidence scoringPostgreSQL checkpointing
01How it runs

From raw input to signed-off output.

agent-runrunning

$ promenaut run payment-schema-mapping

Single MT202 → pacs.009.001.08 run

01

Schema analysis

A deterministic parser reads the block-structured MT message and the target XSD first, for 100% reliable field extraction regardless of variance, then an enrichment step adds human-readable names, data types and formats. No model is used for the structural parse.

02

Mapping generation (gate)

Actual source values are correlated against actual target values, the transformation rule for each is inferred, the existing pattern library is loaded as institutional memory, and a calibrated confidence score is assigned. A human approval gate follows before validation begins.

03

Validation & testing (gate)

Each mapping is replayed against the real output and checked for mandatory coverage, schema compliance, type compatibility, format validation and value reproduction. Twenty test cases and a six-part documentation package are generated. A second gate freezes the mapping version before it is sealed as an immutable snapshot.

02Under the hood

How it actually works.

  • Confidence bands route the work: 0.95+ auto-approves, below 0.80 requires human review; a non-blocking quality check flags low-confidence clusters.
  • A persistent pattern library (date conversion, composite-field split, party resolution, code mapping) is reused across runs: patterns learned on one message type accelerate the next.
  • Handles multi-output targets: one source field can map to both an internal wrapper and the ISO 20022 XML.
  • Fully database-driven execution with PostgreSQL checkpointing for resume at every stage and live progress over SSE.
  • No spec required: the real MT messages and their outputs are the specification.
03Results

What it produced.

Single MT202 → pacs.009.001.08 run

100%

Field coverage

97.7%

Average mapping confidence

Perfect

Pass rate on validation checks

~65s

End to end, brief to sealed package

Test cases and reusable transformation patterns generated automatically; the pipeline paused at the human approval gate exactly as designed.

04Why it's hard

The parts that break naive tools.

Composite fields do not map 1:1

One SWIFT field can pack value-date, currency and amount together; it has to fan out into three separate ISO 20022 fields. A dedicated decomposition pattern handles it.

Reasoning is non-deterministic; parsing must not be

Structural extraction runs on a deterministic parser for 100% reliability; the reasoning step only enriches metadata and correlates values.

Value correlation is the hard cognitive step

Holding the full source and target field sets in mind, tracing values through candidate transformations and calibrating confidence: this one step gets the most capable reasoning in the system.

Trust without a source-of-truth spec

Inferred rules cannot be auto-shipped, so confidence bands, a non-blocking quality check and two hard approval gates keep a human in the loop before anything is sealed.

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