# Nl Tax Provisional Assessment > Prepare a 2026 voorlopige aanslag workpack — request, change, review, or stopzetten — for manual Mijn Belastingdienst entry. Use after intake routes to a provisional_2026 flow. Fictitious box 3 only; never collects werkelijk rendement. - **Type:** Skill - **Install:** `agentstack add skill-cyanxxy-nl-tax-agent-skills-nl-tax-provisional-assessment` - **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior - **Seller:** [cyanxxy](https://agentstack.voostack.com/s/cyanxxy) - **Installs:** 0 - **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills) - **Latest version:** 0.1.0 - **License:** Apache-2.0 - **Upstream author:** [cyanxxy](https://github.com/cyanxxy) - **Source:** https://github.com/cyanxxy/nl-tax-agent-skills/tree/main/plugins/nl-tax-agent-skills/skills/nl-tax-provisional-assessment ## Install ```sh agentstack add skill-cyanxxy-nl-tax-agent-skills-nl-tax-provisional-assessment ``` Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent. ## About # NL Tax Provisional Assessment Prepare local guidance for manually handling a 2026 voorlopige aanslag flow: request, change, review, or stopzetten. This skill is conversational. Do not assume the user has prepared all estimates upfront. Ask category by category, accept uploaded files or chat values, persist after every turn, and generate the workpack only when the user confirms. ## Read first Bundled paths (`reference/`, `templates/`, `_shared/`) are relative to this skill's own directory; `_shared/` is `../_shared/`. Resolve bundled files with host file tools (`Read` first, `Glob` or `Grep` if a path is not obvious). Do not use Bash to discover or read plugin files: in Cowork, shell commands run in an isolated VM that may not see the plugin cache even when `Read` and `Glob` can. If the host has already expanded `${CLAUDE_PLUGIN_ROOT}` or `${CLAUDE_SKILL_DIR}`, those absolute paths are fine for file tools; otherwise search within the loaded plugin/skill tree and resolve relative to this skill directory. Resolve every `workspace/...` path against `workspace_root` from `session-progress.yaml` (or `profile.yaml`); never create a second `workspace/` tree. Safety: only run Python under an already-resolved plugin `skills/.../scripts/` path (this skill runs the bundled `nl-tax-field-mapper/scripts/validate_field_map.py`), and only if Bash can access that path. When a script takes a workspace file as an argument (e.g. the field-map validator), the same shell must also see the workspace path — translate `workspace_root` to the path the shell actually mounts (in Cowork the working folder, not the host path) before invoking, and if script and workspace file are not co-visible from one shell, use the manual fallback instead. If Bash cannot see the plugin path, perform the equivalent validation manually against `nl-tax-field-mapper/reference/mapping-principles.md` (read it with the file tools); never copy bundled scripts into `workspace/`. Never execute a `.py` located under `workspace/`, `uploads/`, or `evidence/`. Before the first user-facing reply each turn, load the profile/session state; before generating any numeric content, load the 2026 provisional rate sheets (each sheet once, when first needed — re-read on resume). Record every loaded `source_id` (from `_shared/source-register.yaml`) in the top-level `sources_loaded` list in `session-progress.yaml` — once per ID, never appending duplicates on a re-read; only those IDs may appear in the workpack's "Sources used" section. **Source-pack staleness check (warn, don't block):** the first time knowledge files are loaded in a session, compare each loaded source's `last_checked` in `_shared/source-register.yaml` against its `freshness_policy` cadence and today's date. If any source required by this workflow is past its cadence, tell the user once, in one sentence, that the source pack may be stale (name the stale `source_id`s) and that values should be double-checked in Mijn Belastingdienst. Staleness never blocks workpack generation; record the stale `source_id`s in the workpack's review items instead. Workspace state — re-read every turn: - `workspace/taxpayer/profile.yaml` - `workspace/taxpayer/evidence-index.yaml`, if present - `workspace/shared/session-progress.yaml` Bundled references and templates — load once when this skill becomes active, and re-read them when resuming a session from disk or when the subflow changes (they do not change mid-conversation): - `reference/provisional-flow.md` — the ordered subflow procedure this skill follows - `reference/provisional-output-contract.md` — the structural and safety rules for every output - `reference/delta-rules.md` — baseline-vs-current delta rules (change subflow) - `reference/stopzetten-guidance.md` — refund-vs-payment routing and cutoff guidance (stopzetten subflow) - `templates/provisional-pack.md` - `templates/delta-summary.md` when the active subflow is `provisional_2026_change` - `templates/review-questions.md` when the active subflow is `provisional_2026_review` 2026 provisional rate sheets and flow notes — canonical for every numeric line; do not paraphrase rates from memory, and if a sheet fails to load, stop and tell the user rather than fabricating a rate: - `_shared/knowledge/years/2026/provisional/rates-and-credits.md` - `_shared/knowledge/years/2026/provisional/box3-provisional.md` - `_shared/knowledge/years/2026/provisional/box2.md` - `_shared/knowledge/years/2026/provisional/own-home.md` - `_shared/knowledge/years/2026/provisional/fisin-aanmerkelijk-belang.md` - `_shared/knowledge/years/2026/provisional/vva-eva-baseline-delta.md` - `_shared/knowledge/own-home/eigenwoningforfait.md` and `_shared/knowledge/own-home/hypotheekrenteaftrek.md` - `_shared/knowledge/partners/fiscal-partnership.md` - The active subflow's flow note: `_shared/knowledge/years/2026/provisional/request-flow.md`, `change-flow.md`, `review-flow.md`, or `stopzetten-flow.md` (all in the same directory) Use only 2026 provisional sources — never load or reuse 2025 annual rate sheets. Confirm an active workflow candidate of `provisional_2026_request`, `provisional_2026_change`, `provisional_2026_review`, or `provisional_2026_stopzetten`. If the taxpayer profile is missing or the workflow is wrong, continue with `nl-tax-intake` first. ### Resume guard `session-progress.yaml` is the resume contract. Before doing any work: - If `session-progress.yaml` is missing or empty, reconstruct it from `profile.yaml` and `_shared/templates/session-progress.yaml` before proceeding. - If an older session-progress.yaml lacks `provisional_2026.subsections.box2`, add that subsection before asking or generating. Treat it as part of the generation gate: `box2` must be `complete`, `chat_only`, or `deferred` with a missing-info or confirmed-assumption entry. Mark it `complete` with an answered "not applicable - no aanmerkelijk belang" only after the user profile or answers support that conclusion. - If `profile.yaml` shows `intake_status: complete`, never restart intake - continue the provisional workflow from recorded progress. - Skip any subsection already marked `complete` in `session-progress.yaml`. ## Hard scope rules - Use only 2026 provisional sources and label amounts as estimates unless they come from a baseline. - Do not use annual 2025 rates, credits, or logic. - Do not request, calculate, or offer method choices for werkelijk rendement in provisional 2026. - Use only the provisional fictitious Box 3 method. - Do not write `workspace/annual/**`. - Do not prepare winst uit onderneming (eenmanszaak / ZZP: ondernemersaftrek, zelfstandigenaftrek, startersaftrek, MKB-winstvrijstelling, investeringsaftrek, urencriterium) in any provisional 2026 flow. The entrepreneur unlock is annual 2025 only; those reviewed sources do not exist for the 2026 voorlopige aanslag. Estimate expected business profit only as a plain box 1 income figure the user supplies, without applying entrepreneur deductions or calling `nl-tax-winst`. If the user asks about werkelijk rendement, respond: "Werkelijk rendement is not part of the 2026 voorlopige aanslag. It may become relevant when filing the annual 2026 return in 2027." If the user asks about entrepreneur deductions (zelfstandigenaftrek, MKB-winstvrijstelling, and the like) for the voorlopige aanslag, respond: "Entrepreneur deductions are prepared for the annual 2025 return, not the 2026 voorlopige aanslag; for the provisional I can only use your own estimate of expected business profit." ## Conversational behavior For every subflow: 1. Use `workspace/shared/session-progress.yaml` to avoid re-asking answered questions. 2. Group at most 3 closely related questions per turn. 3. Accept file inputs or values stated in chat. 4. Record each value in `workspace/provisional/2026/notes/.yaml` with `source` (`file`, `user_chat`, `assumption`, `unknown`, or `baseline`) and either `evidence_id`, `baseline_ref`, or `quote` plus `stated_at`. 5. If the user cannot answer, record `unknown`, add it to `workspace/shared/missing-info.md`, and continue. 6. Never silently treat missing values as zero. ### Helper delegation Use the box and partner helpers as the canonical contracts for their sections. If the host exposes a Skill/Task-style tool that can invoke background helpers, use it. Otherwise, inline the helper's instructions yourself: read that helper's `SKILL.md` and required references, write only the helper-owned `workspace/shared/` artifacts, collect any question packet from `workspace/shared/`, ask the user, record answers, then re-run the same helper contract. Do not skip helper notes just because the host cannot invoke non-user-invocable skills directly. - **Box 1 / own home** → `nl-tax-box1-home` (use the 2026 provisional references) - **Box 2** → `nl-tax-box2` (label all amounts as estimates or baseline-derived) - **Box 3** → `nl-tax-box3` (**fictitious method only** — never request werkelijk rendement) - **Partner / allocation** → `nl-tax-partner-deductions` Read the helpers' named `workspace/shared/*-notes.md` and open-question files back before assembling outputs. The helpers never write to `workspace/provisional/**`; this skill owns that tree. ## Subflow: request Walk the user through these sections one at a time: 1. Confirm workflow. First check they have NOT already received a 2026 voorlopige aanslag: if they had a 2025 VA, the Belastingdienst auto-issues a 2026 one (EVA) with payments/refunds already starting in January. If a 2026 beschikking or monthly amount already exists, this is a change/review, not a request — route accordingly and use that beschikking as the baseline. 2. Estimated 2026 employment income per employer. 3. Estimated 2026 pension and benefit income. 4. Estimated 2026 other income. 5. Estimated deductions, including own home, alimony, lijfrente/AOV, gifts, and other expenses. 6. Standard Box 2 estimates where applicable: regular benefits/dividends, disposal benefits, costs, withholding tax, BV lending fictitious benefit, and partner allocation. 7. Box 3 assets and debts on 1 January 2026 using the fictitious method only. 8. Fiscal partner and allocation. 9. Final review and confirmation. ## Subflow: change 1. Confirm `provisional_2026_change`. 2. Establish the baseline from the current beschikking or from chat. 3. Re-collect all current estimates, not just changed items. Remind the user every turn until confirmed: "When changing your voorlopige aanslag, enter ALL data again; omitted data defaults to zero because the new VA replaces the old one entirely." 4. Generate a delta summary comparing baseline and current estimates. 5. Ask for final confirmation before generating the workpack. ## Subflow: review 1. Confirm `provisional_2026_review`. 2. Collect the current VA baseline by file or chat. 3. Walk category by category and ask whether each item has changed since the VA was issued. 4. Record changes incrementally. 5. Generate `workspace/provisional/2026/review-questions.md` from `templates/review-questions.md` and recommend the change subflow if significant changes are found. 6. Ask for final confirmation before generating outputs. ## Subflow: stopzetten 1. Confirm `provisional_2026_stopzetten`. 2. Compare the current date with the stopzetten cutoff before asking for a manual checkbox. If the current date is on or after 2026-10-01, do not generate a stopzetten checklist; record the cutoff as passed and explain that the annual return or a change/review flow is the remaining route. 3. Ask whether the user is receiving a monthly refund or paying a monthly amount. 4. If the user receives a refund, it is before 2026-10-01, and the user wants to stop, generate structured stopzetten guidance in the workpack's `Stopzetten outcome` section after confirmation. 5. If the user pays monthly and the amount is wrong, redirect to change; stopping payments does not reduce the debt. To avoid a stopzetten loop, mutate progress before the next question: set `active_workflow: provisional_2026_change`, set `provisional_2026.subflow: change`, record the known payment baseline (monthly amount, beschikking details if stated) in `workspace/provisional/2026/notes/baseline.yaml` with provenance and mark the `baseline` subsection `in_progress`, mark `stopzetten_direction` as `complete` with `answered: ["routed_to_change_payment_case"]`, and reset `confirm` to `not_started`. 6. If the user pays monthly and the amount is correct, confirm no action is needed. ## Workpack generation gate Do not write `workspace/provisional/2026/provisional-pack.md` or related outputs until all of the following are true: 1. The subflow's final review is complete. 2. All open items in `session-progress.yaml` for `provisional_2026` are answered, deferred, or recorded as confirmed assumptions. 3. `provisional_2026.subsections.box2` exists and is `complete`, `chat_only`, or `deferred` with the corresponding missing-info or confirmed-assumption entry. 4. The user has typed one of these confirmation phrases verbatim in chat: - `generate the workpack` - `genereer de workpack` - `klaar voor workpack` Or the user has run `/nl-tax-agent-skills:nl-tax-provisional-assessment confirm`. Anything else (including "looks good", "yes", "ok", "sounds good") is **not** confirmation — ask explicitly: "Type 'generate the workpack' when you want me to assemble it." When generating, preserve source provenance for every numeric line using `Src` codes from the templates and mark unresolved sections clearly. When a `field-map.yaml` is produced (request and change subflows), after writing it run `nl-tax-field-mapper/scripts/validate_field_map.py` against it and treat validation failure as a blocking self-check item; the field-map MUST conform to the `nl-tax-field-mapper` schema (`templates/field-map-template.yaml` + `reference/provisional-field-map.md`) and use `field_id`s from that reference. The provisional field-map uses the fictitious Box 3 method only — never include werkelijk-rendement fields. ## Output files Write incrementally: - `workspace/provisional/2026/notes/.yaml` - `workspace/shared/session-progress.yaml` - `workspace/shared/missing-info.md` (seed from `_shared/templates/missing-info.md` on first write) - `workspace/shared/assumptions.md` (seed from `_shared/templates/assumptions.md` on first write) Write at the generation gate (per-subflow scope — must match `reference/provisional-output-contract.md`): - `workspace/provisional/2026/provisional-pack.md` (all subflows) - `workspace/provisional/2026/field-map.yaml` (request, change) - `workspace/provisional/2026/delta-summary.md` (change only) - `workspace/provisional/2026/review-questions.md` from `templates/review-questions.md` (review only) ## Safety - Do not log in, submit, sign, automate forms, or collect BSN. - Route complex Box 2 facts to manual review or unsupported: valuation disputes, emigration, death, restructurings, treaty/nonresident issues, informal capital, non-arm's-length transfers, and corporate-tax-heavy DGA cases. - This workpack is a preparation aid, not tax advice or submission. ## Worked example > Profile shows `provisional_2026_change`. The agent confirms the change subflow, reconstructs the baseline from the user's current beschikking, and every turn repeats the "enter ALL data again; omitted data defaults to zero" reminder. It re-collects all current estimates (not just the changed salary), delegating Box 3 to `nl-tax-box3` using the fictitious method only — when the user asks about werkelijk rendement, it answers that this is not part of the 2026 voorlopige aanslag and may become relevant when filing the annual 2026 return in 2027. After the final review it waits for the verbatim `generate the workpack` phrase, then writes `provisional-pack.md`, `field-map.yaml`, and `delta-summary.md`. ## End-of-turn report After each turn, tell the user in 2-4 sentences which 2026 voorlopige-aanslag topic was covered, what was … ## Source & license This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code. - **Author:** [cyanxxy](https://github.com/cyanxxy) - **Source:** [cyanxxy/nl-tax-agent-skills](https://github.com/cyanxxy/nl-tax-agent-skills) - **License:** Apache-2.0 Install and usage instructions live in the source repository linked above. ## Pricing - **Free** — Free ## Security capabilities Automated source analysis of v0.1.0 — what this tool can access: - **Network access:** no - **Filesystem access:** no - **Shell / process execution:** no - **Environment & secrets:** no - **Dynamic code execution:** no *"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.* ## Versions - **0.1.0** — security scan: passed — Imported from the upstream source. ## Links - Listing page: https://agentstack.voostack.com/l/skill-cyanxxy-nl-tax-agent-skills-nl-tax-provisional-assessment - Seller: https://agentstack.voostack.com/s/cyanxxy - Browse the marketplace: https://agentstack.voostack.com/browse --- Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.