Nl Tax Winst

NL Tax Winst uit onderneming

Background helper for winst uit onderneming preparation notes for the 2025 annual return. It supports the standard IB-ondernemer with an eenmanszaak (the usual ZZP legal form): winst uit onderneming, ondernemersaftrek, MKB-winstvrijstelling, and kleinschaligheidsinvesteringsaftrek.

Use this skill only for source-backed preparation support for annual_2025. There is no provisional entrepreneur flow: never prepare winst uit onderneming for a 2026 voorlopige aanslag.

This helper may be called through a Skill/Task tool or inlined by an owning workflow when no such tool exists. The same output contract applies either way.

Read first

Resolve every workspace/... path against workspace_root from session-progress.yaml (or profile.yaml); never create a second workspace/ tree. _shared/ is the plugin-shared folder at this skill's ../_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.

Read the reviewed 2025 knowledge notes — they are canonical for every rate, amount, and threshold. Never paraphrase a figure from memory; read it from these files and record each source_id in session-progress.yaml → sources_loaded (the owning workflow owns session state, so hand it the ids to append):

• ../_shared/knowledge/years/2025/entrepreneur/ondernemer-criteria.md
• ../_shared/knowledge/years/2025/entrepreneur/ondernemersaftrek.md
• ../_shared/knowledge/years/2025/entrepreneur/mkb-winstvrijstelling.md
• ../_shared/knowledge/years/2025/entrepreneur/investeringsaftrek.md
• ../_shared/knowledge/years/2025/entrepreneur/winst-en-kosten.md
• ../_shared/knowledge/years/2025/entrepreneur/entrepreneur-aangifte.md
• reference/winst-2025.md — how the pieces fit together for the workpack

There are no bundled calculators for this helper. Compute the ordering (winst → minus investeringsaftrek such as KIA → minus ondernemersaftrek → MKB-winstvrijstelling) by hand from the sourced amounts; if the host ever adds a script under an already-resolved plugin skills/.../scripts/ path, run it only when Bash can reach that path, and always keep the declarative fallback of continuing manually from the sourced inputs and rules. Never copy bundled scripts into workspace/, and never execute a .py under workspace/, uploads/, or evidence/.

Do

• Confirm the taxpayer is an ondernemer voor de inkomstenbelasting with an

eenmanszaak, and record whether the urencriterium (or, for the startersaftrek bij arbeidsongeschiktheid, the verlaagd urencriterium) is met.

• Prepare the winst uit onderneming: turnover minus deductible business costs,

then investeringsaftrek such as KIA, then ondernemersaftrek, then the MKB-winstvrijstelling, in that order.

• Prepare the ondernemersaftrek components the case qualifies for

(zelfstandigenaftrek, startersaftrek, S&O-aftrek, meewerkaftrek), reading the 2025 amounts from the knowledge notes.

• Prepare the kleinschaligheidsinvesteringsaftrek from the KIA table when the

taxpayer invested in qualifying bedrijfsmiddelen.

• Note the beperkt-aftrekbare-kosten threshold (or the 80% election), werkruimte

conditions, the private-use-of-a-business-car bijtelling, and the private-vehicle kilometre deduction where they apply — as preparation notes, not final figures.

• Keep outputs suitable for preparation workpacks and review questions.
• When facts are missing, append a structured question packet to

workspace/shared/winst-open-questions.yaml instead of inventing zeros.

Question packet

Append missing inputs to workspace/shared/winst-open-questions.yaml:

- question_id: "annual.winst.ondernemer.status"
  workflow: "annual_2025"
  section: "winst.ondernemer_status"
  prompt_for_user: "Do you run your own business as an IB-ondernemer (eenmanszaak / ZZP), and did you meet the urencriterium in 2025 as described in the entrepreneur knowledge note?"
  acceptable_sources: ["file", "user_chat"]
  evidence_hint: "KvK registration, urenadministratie, winst-en-verliesrekening"
- question_id: "annual.winst.ondernemersaftrek.startersaftrek"
  workflow: "annual_2025"
  section: "winst.ondernemersaftrek"
  prompt_for_user: "For the regular startersaftrek: in 2020-2024, were you not an IB-ondernemer in at least one calendar year, and was the zelfstandigenaftrek applied at most twice in those years? Also say whether there was a geruisloze terugkeer uit a BV in that period."
  acceptable_sources: ["file", "user_chat"]
  evidence_hint: "prior-year aangiften or aanslagen, notes on start date and ondernemersaftrek history"
- question_id: "annual.winst.result.omzet_kosten"
  workflow: "annual_2025"
  section: "winst.result"
  prompt_for_user: "What was your 2025 turnover (omzet) and total deductible business costs? A winst-en-verliesrekening or bookkeeping export is ideal."
  acceptable_sources: ["file", "user_chat"]
  evidence_hint: "winst-en-verliesrekening, balans, facturen"

The calling skill asks these questions, records the answers with source, quote/evidence_id, and timestamp under its own annual notes tree, then re-runs this helper contract. Do not write caller-owned notes.

Never

• Do not log in, automate a browser, sign, or submit anything.
• Do not claim that the helper gives binding tax advice or a final assessment.
• Do not prepare winst uit onderneming for a 2026 voorlopige aanslag; the

entrepreneur unlock is annual 2025 only.

• Do not route complex business cases as standard preparation. Partnerships (VOF,

maatschap, CV) and profit-share allocation, medegerechtigdheid, DGA/BV winst, agrarische ondernemingen, zeevarenden, staking/cessation events, herinvesteringsreserve, oudedagsreserve wind-down, and resultaat uit overige werkzaamheden all go to manual review.

• Do not treat a btw-ondernemer as automatically an IB-ondernemer.
• Do not write field maps, annual/provisional workpack templates, source

registers, supported workflow files, or shared eval data.

Write only winst preparation notes, open questions, or shared review questions under workspace/shared/ when asked by an owning workflow:

• workspace/shared/winst-notes.md
• workspace/shared/winst-open-questions.yaml
• workspace/shared/winst-review-questions.md

Do not write workpacks directly.

Must NOT write to

This helper writes only under workspace/shared/. It must never write to:

• workspace/annual/**
• workspace/provisional/**

Only nl-tax-annual-return and nl-tax-provisional-assessment own those trees. On hosts that do not enforce allowed-tools (for example Codex, which loads the SKILL.md body but does not enforce allowed-tools), treat this as a hard instruction, not just a tool restriction.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: cyanxxy
• Source: cyanxxy/nl-tax-agent-skills
• License: Apache-2.0

Install and usage instructions live in the source repository linked above.