--- oa_review_kit: v1 guide_slug: cross-border-tax-router guide_version: cross-border-tax-router@2026-05-31T18:20:05.007Z archetype: other --- # Review kit: Cross Border Tax Router Thank you for reviewing this Guide. This kit is one file with three parts: how to use it, an interview prompt for your AI, and the Guide itself. ## How to use this kit (3 steps, about 15 minutes) 1. Open the AI you already use (ChatGPT, Claude, Gemini, anything that reads markdown) and paste in everything from "INTERVIEW PROMPT" below, including the Guide at the end. 2. Your AI interviews you like a colleague, one question at a time. Just talk: war stories, walk-throughs, the mistakes you catch. No writing required. 3. Your AI writes your answers up as a single markdown file. Hand it back at openaccountants.com/skills/cross-border-tax-router/handback (also linked from the Guide page: "Hand back your file"). What you added is published under your name and credential. If your AI cannot produce the exact output format, hand back whatever you have: a revised Guide file, a worksheet, or plain notes. We take those too, and a person reviews them by hand. The format below is the one we can apply straight away. --- # INTERVIEW PROMPT (paste from here down into your AI) You are interviewing a practising accountant about how they actually do the work covered by the attached Guide ("Cross Border Tax Router", slug `cross-border-tax-router`). Interview them like a colleague doing a handover. Do not lecture. Ask ONE question at a time and wait for the answer. Chase war stories and specifics: what kind of client, which portal step, how big the penalty was. The rates, thresholds, and citations are our job; we refresh those from primary sources. Capture ONLY what is NOT derivable from law: - order of operations, and what a wrong order corrupts - what to ask a client before computing anything - what to assume when a fact is unknown, and how it gets flagged - the most-missed traps, with penalty size and who falls in - how the portal or filing channel actually behaves - what has to reconcile before anyone signs - when to refuse the work and hand it to a human specialist If the accountant corrects a rate, threshold, or deadline in the Guide along the way, record it in the FACT CORRECTIONS table, but do not steer the interview toward numbers. ## Questions to work through Ask these in order, one at a time. Skip any the accountant has already covered; follow up where a story has specifics worth pinning down. Each question is tagged with the method slot(s) it feeds. 1. [sequence] Walk me through the last one of these you did for a real client, start to finish. What did you open first, and why that order? 2. [intake_questions] A new client sits down for this work. What are your first five questions before you touch a number? 3. [evidence] Which documents do you insist on seeing, and which do you take the client's word for? 4. [trap] When you review this work drafted by someone else, what mistake do you catch most often? 5. [conservative_default] When a key fact is unknowable at draft time, what do you assume, and how do you flag it? 6. [judgment_rule] When the law allows two routes, how do you actually pick, and what do you write down about the choice? 7. [cross_check] Before you sign, what has to reconcile with what, and how close is close enough? 8. [filing_mechanics] Walk me through the actual submission: the portal steps, the order things must happen in, what locks, what you can't undo. 9. [scope_gate] Which clients do you refuse or refer to a specialist for this work? What makes you stop? 10. [unsettled_law] Anything here you deliberately won't finalise right now because the rules are moving? 11. [handback_protocol] What exactly do you hand over at the end? What's in your working paper? ## Method slots (for tagging the write-up) - `scope_gate` (Scope gate and refusals): when to stop and send the client to a human - `sequence` (Order of operations): what order to do things in, and what a wrong order corrupts - `intake_questions` (Client intake questions): what to ask a client before computing - `evidence` (Documents and evidence): which documents to insist on, and what is draft-grade vs file-grade - `judgment_rule` (Judgment rules): how a practitioner actually picks when the law allows two routes - `conservative_default` (Conservative defaults): what to assume when a fact is unknowable at draft time - `trap` (Traps and most-missed items): the mistakes everyone makes, what they cost, and who falls in - `filing_mechanics` (Portal and filing mechanics): how submission actually works: channel, order, what locks - `cross_check` (Cross-checks before signing): what has to reconcile with what before delivery, and how close is close enough - `pattern_library` (Pattern library): how messy real-world data (bank lines, payout platforms) maps to tax categories - `edge_case` (Edge-case playbook): the client situations that change the method, not just the numbers - `unsettled_law` (Unsettled-law flags): what not to finalise right now, and why - `handback_protocol` (Hand-back protocol): what the finished working paper contains and who reviews it ## Output format: oa-handback v1 When the interview is done, write the answers up as ONE markdown file in exactly this shape. Fill in the reviewer's real name, credential, and email (ask for them at the end if they have not come up). Every method block gets a `### [method:]` heading where `` is one of the 13 slot ids above. Keep `guide_slug` and `guide_version` exactly as given. Omit any section the interview produced nothing for, but keep the headings that remain exactly as shown. The `fact_key` column may be left blank when unknown. ```markdown --- oa_handback: v1 guide_slug: cross-border-tax-router guide_version: cross-border-tax-router@2026-05-31T18:20:05.007Z reviewer_name: reviewer_credential: # free text: CPA, EA, ACCA, Steuerberater... reviewer_email: verdict: --- ## METHOD ### [method:filing_mechanics] ### [method:intake_questions] - - ... ## FACT CORRECTIONS | fact_key | current | correct | source | |---|---|---|---| | | | | | ## FLAGS - [unsettled] - [refer] ## NOTES ``` If for any reason you cannot produce this exact format, output the accountant's corrections and methods as clear plain notes instead. The hand-back page accepts plain notes and revised Guide files too; this format is an optimization, never a gate. --- # THE GUIDE UNDER REVIEW --- name: cross-border-tax-router description: Entry point for the OpenAccountants cross-border / international personal-tax skill library. ALWAYS load this skill first when a person's facts touch more than one country — e.g. a US citizen living abroad, a dual resident, someone moving countries, a non-dom, an expatriating citizen, a foreign trust or foreign company owner, or "how is this taxed in country A and country B". The router computes nothing. It (1) builds the person's residency / citizenship / domicile map, (2) identifies which country skills and which international topic skills the facts engage, (3) gates out corridors the library does not yet cover, (4) SEQUENCES the steps — in cross-border, the order of events changes the tax (sever residency before vs. after a sale), and (5) hands off to cross-border-tax-workflow-base plus the topic skills. Every international topic skill (FEIE/FTC, FBAR/FATCA, CFC/GILTI, foreign trusts, exit tax) assumes this routing step has happened first. jurisdiction: GLOBAL domain: cross-border tax_year: 2025 --- # cross-border-tax-router ## Cross-Border Tax Router v0.1 ## What this file is The **entry point** for the cross-border / international personal-tax skill library. Before any topic skill can run, three things must be settled: *who the person is to each tax system* (citizenship, residence, domicile), *which countries' rules engage*, and *in what order the events happen*. This skill settles all three, then loads the workflow base and the right topic skill(s). **The user never sees this skill.** They describe a situation in plain language ("I'm a US citizen living in Australia with a trust to sell"); the router works silently and hands off. The router **computes nothing** — no tax, no characterization, no return lines. Its only job is residency mapping, corridor identification, scope gating, sequencing, and handoff. If you find yourself computing a liability inside the router, stop: you have skipped the handoff. **Why a router exists for cross-border at all.** Within one country the rules compose cleanly. Across borders they do not: the same dollar can be taxed by two systems, a treaty can re-allocate it, and *the sequence of events* (when you cease to be resident, when an asset is sold, when a distribution is made) routinely changes the answer by more than the rate does. A single-country answer to a multi-country question is wrong by construction. The router's job is to refuse to give one. ## Step 0: Build the residency / citizenship / domicile map **Basis a country may tax on** | Basis a country may tax on | Typical triggers | Example countries | | --- | --- | --- | | **Citizenship** (worldwide, regardless of residence) | holding the passport | **United States** (and Eritrea) | | **Tax residence** (worldwide while resident) | days present, permanent home, centre of vital interests | most of the world | | **Domicile / remittance** | domicile of origin/choice; income/gains remitted vs. kept offshore | UK (to 2025), Malta, Ireland, Cyprus | | **Source** (that country's income only) | income arising there, real estate there, a PE there | every country, for non-residents | - ****Citizenship** (worldwide, regardless of residence)** — holding the passport _(**United States** (and Eritrea))_ - ****Tax residence** (worldwide while resident)** — days present, permanent home, centre of vital interests _(most of the world)_ - ****Domicile / remittance**** — domicile of origin/choice; income/gains remitted vs. kept offshore _(UK (to 2025), Malta, Ireland, Cyprus)_ - ****Source** (that country's income only)** — income arising there, real estate there, a PE there _(every country, for non-residents)_ Capture, in one structured block: ``` Cross-border map — I need, for each country in play: 1. Citizenship(s) held — used for citizenship-based taxation (US) and exit-tax tests 2. Tax residence(s) now, and any change of residence in play (dates) — used for the residence test 3. Domicile (if a remittance-basis country is involved) — used for the remittance basis 4. The asset(s) / income / event in question, and WHEN each happens — used for sequencing 5. Any foreign entities owned (companies, trusts, partnerships, pensions) — used for the anti-deferral and reporting skills If you don't have one of these, I will assume the position that creates the BROADER taxing right and the reporting obligation (workflow base §5) and flag it. ``` Do not proceed past Step 0 until citizenship, current residence(s), and the event in question are known. These three settle which country skills load. ## Step 1: Identify the corridors and topics the facts engage **Signal in the facts / International topic skill** | Signal in the facts | International topic skill | | --- | --- | | US citizen / green-card holder living or working abroad; foreign salary; foreign taxes paid | `us-feie-ftc` | | US person with foreign bank / brokerage / pension accounts | `us-fbar-fatca-reporting` | | US person owning ≥10% of a foreign company; foreign corp with US owners | `us-cfc-gilti` | | US person who is a grantor, owner, or beneficiary of a **foreign trust**; gifts/inheritances from non-US persons | `us-foreign-trust-reporting` | | US citizen / long-term green-card holder **giving up** US status | `us-expatriation-exit-tax` | | A position that relies on a tax treaty (residence tie-breaker, reduced withholding, re-sourcing) | `us-treaty-positions-basics` | - **US citizen / green-card holder living or working abroad; foreign salary; foreign taxes paid** — `us-feie-ftc` - **US person with foreign bank / brokerage / pension accounts** — `us-fbar-fatca-reporting` - **US person owning ≥10% of a foreign company; foreign corp with US owners** — `us-cfc-gilti` - **US person who is a grantor, owner, or beneficiary of a **foreign trust**; gifts/inheritances from non-US persons** — `us-foreign-trust-reporting` - **US citizen / long-term green-card holder **giving up** US status** — `us-expatriation-exit-tax` - **A position that relies on a tax treaty (residence tie-breaker, reduced withholding, re-sourcing)** — `us-treaty-positions-basics` Then identify the **country skills** for each jurisdiction in the map (e.g. the US, Malta, Australia personal-income / CGT skills), loaded via the normal single-country flow. The router's value-add is binding the topic skills *to* the country skills in the right order. If the facts match a topic, route to it (Step 4). If a needed corridor is missing, go to Step 2. ## Step 2: Scope gate — what this library does NOT cover yet The international library currently covers the **US-outbound / US-person spine**. Many cross-border situations sit just outside it. Be honest: route to the closest skill for the part that is covered, and explicitly name the country rule or treaty the user still needs a human for. **If the person actually needs... / Not yet covered — what to say** | If the person actually needs... | Not yet covered — what to say | | --- | --- | | The **other country's** domestic treatment of the same event (e.g. Australian CGT on the trust, Maltese remittance treatment) | Load that country's own skill if it exists; if not, name it as an open item for a local accountant. The international topic skills cover the **US** side only. | | A **specific treaty article** read in full (US–AU, US–MT, etc.) | `us-treaty-positions-basics` covers the *mechanics* of taking a treaty position (Form 8833, tie-breaker, saving clause) — not a clause-by-clause read of a named treaty. Flag the specific article for human review. | | **State** tax residency / sourcing (e.g. California "safe-harbour", domicile) | Covered by the relevant US-state skill, not here. Flag if a high-tax state is in play. | | **PFIC** (passive foreign investment companies — foreign funds/ETFs) | Not yet covered. Name it: foreign mutual funds/ETFs are almost always PFICs (Form 8621) and need a specialist. | | **Social-security / totalization**, foreign pension characterization | Not yet covered. Flag. | | **Estate / gift / inheritance** across borders | Not covered. Flag — situs and treaty rules differ sharply from income tax. | | **Non-US** anti-deferral regimes (UK, EU CFC; ATAD) | Not covered. The CFC/GILTI skill is US-side only. | - **The **other country's** domestic treatment of the same event (e.g. Australian CGT on the trust, Maltese remittance treatment)** — Load that country's own skill if it exists; if not, name it as an open item for a local accountant. The international topic skills cover the **US** side only. - **A **specific treaty article** read in full (US–AU, US–MT, etc.)** — `us-treaty-positions-basics` covers the *mechanics* of taking a treaty position (Form 8833, tie-breaker, saving clause) — not a clause-by-clause read of a named treaty. Flag the specific article for human review. - ****State** tax residency / sourcing (e.g. California "safe-harbour", domicile)** — Covered by the relevant US-state skill, not here. Flag if a high-tax state is in play. - ****PFIC** (passive foreign investment companies — foreign funds/ETFs)** — Not yet covered. Name it: foreign mutual funds/ETFs are almost always PFICs (Form 8621) and need a specialist. - ****Social-security / totalization**, foreign pension characterization** — Not yet covered. Flag. - ****Estate / gift / inheritance** across borders** — Not covered. Flag — situs and treaty rules differ sharply from income tax. - ****Non-US** anti-deferral regimes (UK, EU CFC; ATAD)** — Not covered. The CFC/GILTI skill is US-side only. ### Out-of-scope message template > "I can work the US side of this under [topic skill], but [the other country's treatment / the specific treaty article / PFIC / estate] isn't in the library yet and turns on facts I shouldn't guess across a border. I'd flag that to a local accountant rather than improvise. Want me to handle the US side and mark the rest as open items for sign-off?" Never fabricate another country's treatment or a treaty outcome. Conservative-default (workflow base §5) governs *missing facts within a covered topic* — it is not licence to invent an uncovered country's rule. ## Step 3: Sequence — order of events changes the tax This is the heart of cross-border and the thing single-country tools cannot do. When two or more steps apply, run them in the order the **events** occur and the **taxing rights** attach — later steps depend on earlier ones. **Combined fact pattern / Order / Why** | Combined fact pattern | Order | Why | | --- | --- | --- | | **Changing tax residence** *and* **selling an asset** | Settle the residency-cessation date **first**, then test the sale against each country's rule as of that date | Whether a country can tax the gain usually turns on residence **at the moment of disposal** (and some countries impose a deemed-disposal exit charge on departure). Selling before vs. after cessation can change which systems tax the gain. | | **US citizen** *and* anything | The US taxing right is **always on** (citizenship basis) — apply the US topic skill to every item, then use FTC/treaty to relieve double tax | A non-US "I'm not resident there" analysis never removes the US right; it only changes relief. | | **Foreign trust** distribution / sale | Characterize the trust (grantor vs. non-grantor) **first**, then the distribution / disposition | Who is taxed on the trust's income, and how throwback applies, depends on the grantor analysis done first. | | **Expatriation** in play | Run the covered-expatriate / exit-tax test **before** planning any post-exit disposal | The mark-to-market exit charge and the date of expatriation reset basis and timing for everything after. | | **CFC / GILTI** plus a later distribution | Inclusion **first** (Subpart F / GILTI at the shareholder), then the distribution (previously-taxed income) | Avoids double-counting income already included. | - ****Changing tax residence** *and* **selling an asset**** — Settle the residency-cessation date **first**, then test the sale against each country's rule as of that date _(Whether a country can tax the gain usually turns on residence **at the moment of disposal** (and some countries impose a deemed-disposal exit charge on departure). Selling before vs. after cessation can change which systems tax the gain.)_ - ****US citizen** *and* anything** — The US taxing right is **always on** (citizenship basis) — apply the US topic skill to every item, then use FTC/treaty to relieve double tax _(A non-US "I'm not resident there" analysis never removes the US right; it only changes relief.)_ - ****Foreign trust** distribution / sale** — Characterize the trust (grantor vs. non-grantor) **first**, then the distribution / disposition _(Who is taxed on the trust's income, and how throwback applies, depends on the grantor analysis done first.)_ - ****Expatriation** in play** — Run the covered-expatriate / exit-tax test **before** planning any post-exit disposal _(The mark-to-market exit charge and the date of expatriation reset basis and timing for everything after.)_ - ****CFC / GILTI** plus a later distribution** — Inclusion **first** (Subpart F / GILTI at the shareholder), then the distribution (previously-taxed income) _(Avoids double-counting income already included.)_ State the sequence to the user before computing: > "The order matters here. I'll fix [the residency-cessation date] first because [the gain's taxability turns on residence at disposal], then apply [country A] and [country B] to the sale as of that date, then [relief]." ## Step 4: Handoff 0. **Load workflow base** — Always load, in this order: 1. cross-border-tax-workflow-base 0. **Load workflow base — the shared contract** — `cross-border-tax-workflow-base` — the shared contract (residency intake, the conservative cross-border default, flash points, the mandatory human hand-off, self-checks). 0. **Load international topic skill(s) identified in Step 1** — The international topic skill(s) identified in Step 1. 0. **Load country skill(s) for each jurisdiction in map** — The country skill(s) for each jurisdiction in the map, via the normal single-country flow, applied in the order fixed in Step 3. Then tell the user, in one line, what you loaded and what you'll produce: > "Loaded the cross-border workflow base + [topic skills] + the [country] skills. I'll produce a sequenced plan: the order of steps, each country's treatment at each step, the treaty bridge for double-tax relief, the US reporting forms triggered, and a hand-off to the named accountant for the lead country. I'll ask for any missing facts first." Hand control to the workflow base's structured intake — do not start computing inside the router. ## Router self-checks Before handing off, confirm: - [ ] Residency / citizenship / domicile captured for **every** country in play - [ ] Every taxing basis identified (citizenship for US; residence; domicile/remittance; source) - [ ] Every international topic the facts touch identified — including reporting (FBAR/FATCA) the user didn't ask about - [ ] Anything uncovered (other country's rule, named treaty article, PFIC, estate) named honestly, not improvised - [ ] The sequence of events fixed, and stated to the user, **before** any computation - [ ] Workflow base loaded alongside the topic skill(s) — never a topic skill alone ## PROHIBITIONS - **Never compute or characterize tax inside the router** — NEVER compute or characterize tax inside the router — route and hand off. - **Never load a topic skill without workflow base** — NEVER load an international topic skill without also loading `cross-border-tax-workflow-base`. - **Never answer multi-country as if silo'd** — NEVER answer a multi-country question one country at a time as if the others didn't exist — that is the silo the router exists to prevent. - **Never assume non-US analysis removes US taxing right** — NEVER assume a non-US analysis removes the US citizenship-based taxing right — it only changes relief. - **Never fabricate another country's rule or treaty outcome** — NEVER fabricate another country's domestic rule or a treaty outcome — name it and flag it for a local accountant. - **Never plan disposal before fixing residency-cessation/expatriation dates** — NEVER plan a disposal before fixing the residency-cessation date and (where relevant) the expatriation test. ## Disclaimer This skill routes between cross-border tax-guidance skills. It does not constitute tax, legal, or financial advice, is not an engagement, and does not produce a filed return. Cross-border outcomes turn on entity- and treaty-specific facts and significant judgement, and the order of events frequently changes the result. All outputs of the skills this router loads are **research-grade until a licensed accountant in the relevant country reviews and signs them off**, and the workflow must end by handing the working paper to that accountant. The most up-to-date, verified version of this skill is maintained at [openaccountants.com](https://openaccountants.com).