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    🧾 Invoice & Estimate Linter

    by JustHandled Labs

    Check an invoice or estimate before you send it: missing document number, dates, or payment terms, totals that do not add up, tax gaps, missing remittance details, and slow terms with no late fee. Read-only, plain-English findings. Not accounting advice.

    Updated Jul 2026
    Security scanned
    Cursor

    $12

    · or 60 credits

    30-day refund guarantee

    Secure checkout via Stripe

    Included in download

    • Audit invoice arithmetic to catch calculation errors
    • Ensure all payment remittance instructions are present
    • file_read automation included
    • Ready for Cursor
    • Instant install

    Media gallery

    See it in action

    You say

    Check the invoice at path/to/invoice_v2.md for any errors or missing fields before I send it to the client.

    Your agent does

    I found 2 issues in invoice_v2.md: [IEL003] ERROR: Grand total ($1,250) does not match line items ($1,200). [IEL006] WARNING: Missing payment or remittance instructions. Please correct the arithmetic and add your banking details before sending.

    About This Skill

    The problem

    Manual invoice reviews are prone to arithmetic errors and missing compliance fields. Sending an invoice with broken math or missing payment instructions delays your payout and looks unprofessional.

    What it does

    • Validates line item arithmetic, subtotals, and tax calculations for document accuracy.
    • Scans for missing mandatory fields including document numbers, issue dates, and due dates.
    • Identifies missing seller or buyer identity blocks and tax identifiers.
    • Flags unfavorable payment terms such as high net-term thresholds or missing late-fee clauses.
    • Reports findings by severity and rule ID without modifying your source files.

    Frameworks & tools

    Python script compatible with MD, TXT, CSV, and JSON files. Supports stdin for raw text pipes.

    Why this beats prompting it yourself

    Static prompts often miss subtle math errors or overlook specific fields like remittance instructions. This skill uses a structured rule engine to ensure every check, from IEL001 to IEL009, is applied consistently to every document.

    Use cases

    • Reviewing markdown-based invoices before generating a PDF.
    • Double-checking arithmetic on JSON or CSV export data.
    • Auditing contractor estimates for missing terms or identity info.

    Known limitations

    Validates document structure and math only. It does not verify if your specific tax rates or amounts are legally correct for your jurisdiction.

    Use Cases

    • Audit invoice arithmetic to catch calculation errors
    • Ensure all payment remittance instructions are present
    • Flag slow net-60 terms or missing late-fee clauses
    • Verify buyer and seller identity blocks are complete

    Reviews

    No reviews yet - be the first to share your experience.

    Only users who have downloaded or purchased this skill can leave a review.

    Security Scanned

    Passed automated security review

    Permissions

    Read Files

    Allowed Hosts

    www.agensi.io

    File Scopes

    invoice-estimate-linter/**
    **/*.md
    **/*.txt
    **/*.csv
    **/*.json

    Read Files only. It reads the invoice or estimate you point it at, or text you paste via --stdin, as plain text. It does not run code, read your live environment, use secrets, or send anything anywhere. No write, shell, or network.

    Tags

    invoicing
    accounting-tools
    linting
    business-ops

    Runs anywhere a coding agent can execute a Python 3 script. Tested with Claude Code, Cursor, Codex CLI, Windsurf, and Cline. Python 3 standard library only: no third-party packages, no network calls, and it never runs your code. Reads .md, .txt, .csv, and .json invoices or estimates, or pasted text via --stdin. Rules live in an editable references/invoice-rules.json you can tune.

    Creator

    JustHandled Labs

    JustHandled Labs builds focused agent skills for the work nobody wants to do by hand. Each one is a single repeatable job done well: catching the security and data mistakes that quietly ship, keeping docs and tests honest, gating the commands an agent is about to run, sharpening writing, and handling the founder chores around launches, outreach, and brand setup. Not generic AI productivity. Specific workflows that are easy to run, review, and repeat. Maintained by H.J. Westerfield, with a background in communications, editing, project coordination, customer support, and practical AI systems. Tools for people who want useful automation without theatrical complexity.

    Frequently Asked Questions

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