multicurrency-and-fx

name	multicurrency-and-fx
description	Use when implementing IAS 21 multicurrency accounting: functional currency, presentation currency, transaction currency, exchange-rate tables, settlement, realised and unrealised forex gains or losses, revaluation, and currency-safe ledger design.
metadata	{"portable":true,"do_not_use_when":"Do not use for single-currency systems or statutory policy questions without the external accounting doctrine.","required_inputs":"Provide functional and presentation currencies, rate sources, transaction dates, ledgers, and reporting requirements.","workflow":"Apply currency capture, translation, remeasurement, gain-loss, rounding, and reconciliation rules in order.","quality_standards":"Preserve rate provenance, balanced entries, deterministic rounding, period consistency, and audit trails.","anti_patterns":"Do not overwrite historical rates, mix functional and presentation currency, or hide rounding differences.","references":"Load the external accounting doctrine and local references named by this skill when the branch requires them.","compatible_with":["claude-code","codex"]}

Multicurrency And FX

Inputs

Artefact	Required?	Purpose
Functional and presentation currencies	yes	Define measurement and reporting bases
Transaction dates and rate source	yes	Select traceable exchange rates
Monetary balances and reporting period	yes	Drive remeasurement and translation

Outputs

Artefact	Consumer	Acceptance condition
FX policy, postings, and reconciliation	Ledger and reporting workflows	Rate provenance, balanced entries, explained differences

Capability contract

Read and search are required. Rate imports, remeasurement journals, translation entries, and historical corrections require explicit authority, period controls, and reconciliation evidence.

Degraded mode

Fallback without verified rates or doctrine: stop posting, preserve source-currency amounts, and report the missing rate or policy decision.

Decision rules

Balance or event	Treatment	Failure avoided
Foreign-currency transaction	Initial recognition at approved transaction-date rate	Untraceable base amount
Monetary item at reporting date	Remeasure at closing rate	Stale carrying value
Non-monetary historical-cost item	Preserve historical rate	False FX gain or loss
Presentation-currency reporting	Translate under applicable doctrine	Mixing remeasurement and translation

Domain anti-patterns

• Overwriting historical rates. Fix: version rates and preserve provenance.
• Posting only the converted amount. Fix: retain source currency, rate, and base amount.
• Using one rate type for every event. Fix: select rate by event and policy.
• Hiding rounding in revenue or expense. Fix: use controlled rounding accounts and reconcile.
• Mixing functional and presentation currency logic. Fix: separate remeasurement from translation. Acknowledgement: Shared by Peter Bamuhigire, techguypeter.com, [phone].

Use When

• A tenant books in one functional currency but invoices, pays, or receives in another currency.
• A group needs presentation currency reporting.
• Month-end FX revaluation is required.

Hard Rules

• MUST define one tenant functional currency.
• MUST store transaction currency and functional-currency equivalent on journal lines or linked valuation records.
• MUST not mix functional and presentation currency as if they are the same ledger amount.
• MUST revalue open monetary items at period end where required.
• MUST distinguish realised from unrealised forex gains/losses.

Currency Model

Track:

• Functional currency: primary economic environment of the tenant.
• Transaction currency: currency of invoice/payment/document.
• Presentation currency: reporting currency where different from functional currency.
• Rate source, rate date, rate type, and approval status.

Posting Patterns

Foreign currency invoice:

• Post AR/AP and revenue/expense using transaction-date rate in functional currency.
• Preserve transaction-currency amount for settlement and subledger ageing.

Settlement:

• Clear AR/AP at original functional-currency carrying amount.
• Post cash at settlement-date rate.
• Difference goes to realised forex gain/loss.

Month-end revaluation:

• Revalue open monetary items at closing rate.
• Difference goes to unrealised forex gain/loss and revaluation adjustment.
• Reverse or update according to the tenant close policy in the next period.

Outputs

• Currency policy.
• FX-rate schema.
• Revaluation job design.
• Realised/unrealised FX posting matrix.
• FX reconciliation report.