Use this first, before any generation or validation call, to discover the
exact ``message_type`` strings this server accepts (e.g.
``pacs.008.001.08`` FI-to-FI Customer Credit Transfer). To learn a type's
required fields or full schema, call ``get_required_fields`` or
``get_input_schema`` instead.

Returns a list of ``{"message_type": ..., "name": ...}`` dictionaries, one
per supported message type.

Scheme profiles (CBPR+, HVPS+, Fedwire, CHAPS, T2 RTGS, SCT Inst, generic)
layer rail-specific rules on top of base ISO 20022. Use this to discover
the ``scheme`` names accepted by ``get_scheme`` and ``validate_scheme``.

Registry aliases (e.g. ``cbpr+``, ``cbprplus``) collapse to their canonical
profile, so each profile appears exactly once. Returns a list of
``{"scheme": ..., "name": ...}`` dictionaries.

Use this to inspect a rail's constraints -- whether the UETR is mandatory,
the permitted charge bearers, remittance-info length cap, per-message
transaction cardinality, pinned message versions, and which parties must
carry an LEI -- before assembling or validating a batch.

Args:
    scheme: A registered scheme profile name (see ``list_schemes``).

Use this for a quick checklist of the mandatory columns before building
payment records. For full type/format constraints (not just which fields
are required), call ``get_input_schema`` instead.

Args:
    message_type: A supported ISO 20022 pacs message type.

Use this to learn every field, its type, and its constraints before
assembling records, or to drive a form/UI. For just the required-field
names use ``get_required_fields``; to check records against this schema use
``validate_records``.

Args:
    message_type: A supported ISO 20022 pacs message type.

Use this before ``generate_message`` to catch structural/type errors per
record and get a row-by-row error report. This checks JSON-Schema shape
only; to check a batch against a rail's usage guidelines use
``validate_scheme``.

Returns a report ``{"is_valid": bool, "total": int, "valid": int,
"errors": [...]}``.

Args:
    message_type: A supported ISO 20022 pacs message type.
    records: One or more flat payment records to validate.

Use this to check a batch against a rail's rulebook (CBPR+, HVPS+,
Fedwire, CHAPS, T2 RTGS, SCT Inst) -- charge-bearer restrictions, UETR
presence, remittance-info length, and per-message transaction cardinality.
This is complementary to ``validate_records`` (JSON-Schema shape).

Returns ``{"scheme": str, "is_valid": bool, "total": int,
"violations": [...]}``.

Args:
    scheme: A registered scheme profile name (see ``list_schemes``).
    records: One or more flat payment records to check.

This is the primary generation tool: pass payment records you already hold
in memory and receive an XSD-validated XML document; no file is written.
Run ``validate_records`` first to surface record-level errors, and
``list_message_types`` to confirm the ``message_type`` string.

Returns the validated XML document as a string, or an ``{"error": ...}``
payload (serialized) if generation fails.

Args:
    message_type: A supported ISO 20022 pacs message type.
    records: One or more flat payment records.

Use this to check an externally produced XML document against the official
ISO 20022 schema. To generate a document that is already XSD-validated,
use ``generate_message`` instead.

Returns ``{"message_type": str, "is_valid": bool}``.

Args:
    message_type: A supported ISO 20022 pacs message type.
    xml: The raw XML document to validate.

Use this on the receiving side to identify what a message is -- its
``msg_def_idr`` (e.g. ``pacs.002.001.10``), family, version, and any
Business Application Header -- before processing it. Handles both bare
``Document`` messages and BAH-wrapped envelopes.

Returns a dict with ``msg_def_idr``, ``msg_family``, ``version``,
``root_local_name``, ``namespace_uri``, ``envelope_wrapped`` and ``bah``.

Args:
    xml: The raw inbound XML message.