I am an accountant in Newcastle, Australia. I build open source tools for cash-flow modelling, month-end review and Australian tax and payroll calculations.

Website · Tools · Evaluations · Credentials and evidence

• Explain profit and cash differences: the fictional Newcastle cash-flow case shows $35,957.55 quarterly profit and a $25,160 cash shortfall. Read it in your browser; changing the receipt delay needs desktop Excel.
• Calculate in Excel: the Ozzit formula and workbook extract $100 GST from a wholly taxable $1,100 amount. Needs Microsoft 365 or Excel 2024 or later.
• Review a month-end close: Monthly Close Controls reports 8 exceptions, including a $250 creditors difference. Read it in your browser; reproducing the pack needs Git and Rust.

Each example includes its workings, version and review boundary.

• Provisional member of Chartered Accountants ANZ
• SAP S/4HANA certified in Financial Accounting (FI) and Management Accounting (CO)
• Xero Certified Specialist, Level 3, awarded 1 July 2026 and valid until 1 July 2027

Read the certificate in the evidence register, or explore my Xero trial balance export and review workflow.
_{The badge is Xero's artwork, taken from that certificate.}

• au-fpa-pack: Australian cash-flow forecasts and management briefings using fictional businesses. Extends Guiderail's openfpa.
• Accounting Review Pipeline: Xero exports, month-end exceptions and workpaper review packs, with Excel and Power BI components.
• Ozzit: 143 native Excel LAMBDA functions plus 5 help tables for financial modelling and GST arithmetic, with editable examples. No macros or add-ins; needs Microsoft 365 or Excel 2024 or later. What it covers and what it needs.
• Australian Accounting: Tax and payroll calculation packages, plus a local Model Context Protocol (MCP) server for supported tools. Install it with uvx aus-accounting-mcp.
• Australian Accounting Skills: AI-assisted preparation workflows for public practice and subcontractor accounting, with validation cards and recorded model runs.
• llm-tax-guardrails: APES 110 and TPB Code controls, refusal patterns and evaluation fixtures for firms using LLMs in tax work. Conclusions stay with the registered practitioner.
• au-tax-legislation-corpus: Builds retrieval material from in-force Commonwealth tax legislation on the Federal Register of Legislation, with source and provenance records. It is a finding aid, not authorised legislation.

Each repository shows its own CI, coverage and OpenSSF Scorecard results in its README.

flowchart TB
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    assistant["Assistant using<br/>accounting skills"] <--> mcp["Australian Accounting<br/>MCP server"]
    mcp -->|Calculations| engines["Calculation packages"]
    assistant -->|Workpapers and exceptions| reviewer["Authorised human review"]
    official["Federal Register<br/>of Legislation"] -->|Corpus build| corpus["Legislation corpus<br/>Finding aid"]
    corpus -. Locate provisions .-> reviewer
    official -. Check authority .-> reviewer
    style engines fill:#990024,stroke:#FFFFF0,stroke-width:2px,color:#FFFFF0
    style reviewer fill:#E7162F,stroke:#FFFFF0,stroke-width:2px,color:#FFFFF0
    classDef external fill:#745EB1,stroke:#FFFFF0,stroke-width:2px,color:#FFFFF0
    class official external

To get in touch, use the contact page.

_{Not advice. I am not a registered tax agent or BAS agent and take no advice, return-preparation, tax-treatment confirmation or lodgement requests. The tools are review aids that never lodge or write to ledgers; the reviewer keeps judgement and sign-off. Examples use fabricated data, and support covers software issues only, so please send no taxpayer information.}

_{Raiding ledgers, not tombs.
Made in Newcastle, Australia by Ryan Duguid.}