iso20022-mcp

validate

Read-onlyIdempotent

Checks ISO 20022 records against a message type's JSON Schema before XML generation, verifying required fields, types, dates, and IBAN/BIC constraints.

Instructions

Validate records for a message type against its JSON Schema, via the family's backing server. When to use: Ahead of 'generate', to verify record field types, required fields, date formats (YYYY-MM-DD), and IBAN/BIC constraints without generating XML. Not for: Raw XML documents; the backing server's XSD validation tools and 'parse' handle those. Behavior: Pure deterministic validation; read-only and idempotent with zero network I/O.

Input Schema

Name	Required	Description	Default
`records`	Yes	List of flat record objects (field name → value). Field names come from the family's input schema — call describe(message_type) for the required fields. For pain.001 credit transfers the key fields are: id, date ('YYYY-MM-DD' accepted), initiator_name, payment_id, requested_execution_date ('YYYY-MM-DD'), debtor_name, debtor_account_IBAN, debtor_agent_BIC, creditor_name, creditor_account_IBAN, creditor_agent_BIC, payment_amount (alias 'amount'), currency (alias 'payment_currency'), remittance_information; batch_booking takes JSON true/false, and nb_of_txs/ctrl_sum are computed automatically. IBAN and BIC values are strictly validated, never coerced.
`message_type`	Yes	ISO 20022 message type, e.g. 'pain.001.001.09', 'pacs.008' or 'camt.053'. For pain messages a fully-versioned type is preferred; the bare family name 'pain.001' resolves to 'pain.001.001.09'.

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.0.5Jul 29, 2026

TDQS

A4.7/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint and closed-world behavior, so the 'read-only and idempotent' phrasing is partially redundant. It nonetheless adds real context beyond the annotations: 'pure deterministic validation' and 'zero network I/O', plus the specific class of checks performed (types, required fields, date formats, IBAN/BIC).

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Purpose is front-loaded, then cleanly labeled 'When to use:', 'Not for:' and 'Behavior:' blocks. It is dense but every clause carries information an agent needs, with no filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With an output schema present, return values need no explanation, and the description covers prerequisites, the validation scope, side-effect profile and sibling alternatives. Nothing an agent needs to invoke this two-parameter tool is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and the records parameter is exhaustively documented, so the schema does the heavy lifting. The description still adds meaning by framing the parameters as validation targets: it names the accepted date format (YYYY-MM-DD) and the IBAN/BIC constraints enforced, telling the agent what the two inputs are scrutinized against.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The first sentence states a specific verb (validate) and resource (records for a message type against its JSON Schema), and even names the mechanism (the family's backing server). It clearly separates itself from 'generate' and 'parse' by describing validation-before-generation rather than XML production or parsing.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives an explicit 'When to use' (ahead of 'generate' to verify types, required fields, date formats and IBAN/BIC) and an explicit 'Not for' boundary (raw XML, XSD tools, and 'parse'). Both the triggering condition and the excluded cases are stated, leaving nothing to inference.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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