Request-local payment policies

Install pain001[rules] to add CEL predicates to the existing schema and scheme checks. Policies report findings; they never repair payment data. A true predicate produces a finding. Only error severity blocks generation.

- id: FRIDAY-HIGH-VALUE
  where: payment_amount > 50000 && day_of_week(requested_execution_date) == "Friday"
  severity: error
  message: "High-value Friday payments require a different execution date."

Save this as rules.yaml and run:

pain001 validate -t pain.001.001.03 -d payments.csv \
  --scheme sepa-sct,custom --rules rules.yaml

generate accepts the same policy file. REST validation, synchronous generation and background generation accept the YAML text in the rules request field. Paths are accepted only by the CLI, not by inline REST rules. Each request owns its policy instance; it does not modify the plugin registry. Schema validation still runs, and custom rules compose with built-in or registered scheme profiles.

Predicates use flat record field names. Numeric schema fields are exact decimals. Use decimal("12.34") for fractional thresholds; floating-point literals are rejected. Available helpers are day_of_week(iso_date), country_of_iban(valid_iban), is_business_day(iso_date, country_code) and decimal(text). Weekday names are English. Business days mean weekdays excluding national public holidays, not a bank’s settlement calendar. Calendar years are limited to 1900–2100.

An IBAN does not identify the account currency. currency_of_iban is therefore deliberately unsupported: use the explicit currency or payment_currency field. No external service or bank data is queried.

Limits: 64 KiB policy text, 64 rules, 2,048 characters and 512 AST nodes per expression, and 4,096 characters per referenced string field. YAML aliases, anchors and tags, CEL collection macros and non-whitelisted calls are rejected. Syntax, missing-field and evaluation errors fail closed. Diagnostics identify the rule without returning an interpreter traceback containing rows. Policies are bounded synchronous computations, not a general-purpose script runtime. See ADR-0006.

For review-only repair candidates, the MCP suggest_record_fix tool accepts a record and an error with field and rule keys. Supported rules are CHARSET, FIELD-LENGTH, DATE-FORMAT and MISSING-REQUIRED. Length limits come from bundled schemas, ambiguous dates are refused, and missing fields receive visibly marked placeholders. Every patch requires review and full revalidation. IBANs, BICs, account identifiers, amounts and currencies are always refused, even for whitespace-only changes. Nothing is applied to the record automatically.