Use RevExOS Tools Inside Claude, ChatGPT and Codex

Connector URL

Setup

Setup in ChatGPT and Codex

What's available today

• parse_invoice: give it a public link to an invoice PDF or image (or, in ChatGPT, attach the file) and get back the header fields, every line item, and a check that the totals add up. Same engine as the Invoice Parser. The file is not stored.
• parse_purchase_order and match_po_to_invoice: read a purchase order, or compare it with the invoice billed against it line by line, the same checks as the three-way match checker.
• generate_ar_collection_email: the same logic behind the AR Collections Email Generator.
• Calculators: calculate_proration, build_revrec_schedule, calculate_late_payment_interest and calculate_invoice_due_date run the same code as the proration, revenue recognition, late payment interest and due date calculators, so the numbers match the site.

The document tools and the email generator need an email address (document tools: 5 uses per email per day). RevExOS uses it only to send occasional updates about new free AP/AR tools, never spam. The calculators need nothing.

Install the RevExOS Q2C Kit

Free, open-source quote-to-cash skills for Claude and Codex: quotes, contract handoff, PO to invoice, three-way match, billing and proration, payment terms and late fees, collections and revenue recognition, billing platform selection, and invoice parsing. Installing it also adds this connector and the commands /quote, /parse-invoice, /dunning, /prorate and /revrec-schedule.

claude.ai, Claude Desktop or Cowork: Customize → Plugins → Add → Add marketplace → Add from a repository, enter prab-hub/revexos-q2c-kit and click Sync. Then open the Discover tab, search RevExOS and install RevExOS Q2C Kit (adding the marketplace alone installs nothing).

Codex: run codex plugin marketplace add prab-hub/revexos-q2c-kit, then install it from /plugins.

Claude Code: run /plugin marketplace add prab-hub/revexos-q2c-kit, then /plugin install revexos-q2c-kit@revexos-q2c-kit. Everything in the kit is on the Q2C Kit page.

Parse invoice files with the Claude skill

In Claude, the connector needs a public link. To parse a file you uploaded to Claude or have on disk, install the RevExOS Invoice Parser skill (free, open source). It returns the same fields and totals checks, and can save CSV or JSON.

Limits: 2 parses a day per network, 5 with an email. Files up to 3MB. The file is not stored.

Troubleshooting

"405" or "Not found" when adding the connector

Check the URL is exactly https://revexos.com/api/mcp.

"Couldn't determine how this server signs in"

Expected: the server needs no sign-in. Click Continue anyway, then Connect.

Skill fails with "Tunnel connection failed: 403 Forbidden" or "connect_rejected"

Your network policy for code execution is blocking revexos.com. Add it to the allowed domains (step 3 above). Retrying without that won't help.

Added the marketplace in Claude, but the plugin is not under Yours

Adding a marketplace only makes its plugins available. Open the Discover tab, search RevExOS and click install. To pick up a newer version, use Manage marketplaces → ⋮ → Sync.

ChatGPT does not show new tools, or asks for a link instead of using an attached file

ChatGPT keeps the tool list from when the server was added. Remove the RevExOS plugin and add it again to refresh it.

parse_invoice says the link returned a web page or a login screen

The link has to download the file directly and publicly. Google Drive links work when shared as "Anyone with the link". For a file on your computer, use the skill instead.