Plumbline

For Claude, ChatGPT and Gemini

Check a funding package from your chat window.

Ask your assistant to look at a funding request and its invoices. Plumbline runs the same twelve checks every time, quotes the numbers it verified, and names what it could not. Setup takes about a minute.

A person makes every funding decision

Copy this link first. Every setup below asks for it.

https://mcp.plumbline.cloud/mcp

Set it up

Pick the assistant you already use. There is no account to create, nothing to install, and no password to enter.

Claude

Works on any plan. A free account can hold one of these at a time.

  1. Open your settings and go to Connectors.
  2. Press Add custom connector.
  3. Paste the link into the box. Name it Plumbline.
  4. Press Add. Claude opens a sign-in window; pick Continue with Google and use your work account.

You are done when Plumbline appears in your connector list. Start a new chat and ask it one of the questions below.

On a Team or Enterprise plan an owner adds it once for everybody, and you press Connect on the row they created.

ChatGPT

Needs a paid plan (Plus, Pro, Business, Enterprise or Edu) and a web browser. The phone app cannot do this yet.

  1. Open Settings, then Security and login, and switch on Developer mode.
  2. Go to Plugins and press the plus button.
  3. Name it Plumbline and paste the link into the connection box.
  4. Choose OAuth, create it, and sign in with Google when the window opens.
  5. ChatGPT lists six tools it found. Switch them on.

You are done when those six tools are switched on. Your new app sits under Drafts until someone publishes it.

To give it to a whole team, an admin opens Workspace Settings, then Apps, and publishes it from Drafts.

Gemini

Two different routes, depending on which Gemini your company gave you.

  1. Gemini Enterprise. An administrator opens Data stores, presses Create data store, and picks Custom MCP Server.
  2. They paste the link, choose OAuth, name it Plumbline, and sign in with Google when asked.
  3. The Gemini app. Open Settings, then Connected Apps, then Add a custom app, and paste the link.

You are done when Plumbline shows up in your app or data store list.

The Gemini app route is open to personal Google accounts in the United States only. A work or school account has to go the Enterprise route.

Claude Code and the MCP Inspector were connected to this server and checked on 2026-09-15. The three setups above follow each vendor's current published instructions and have not yet been captured against this server.

Ask it plainly

Plain questions work. You never have to name a tool.

“Check this funding request against the invoices and tell me what doesn't add up.”

“Which checks couldn't you finish, and what document is missing?”

“Write up what you found for the person who has to approve this.”

Nothing of yours is needed to try it. Ask for the sample package with a missing document, and watch eleven of the twelve checks report that they never ran.

Where it stops

It will

  • Run the same twelve checks, in the same order, every time
  • Name every check it could not run, and say why
  • Quote the amounts and names it verified
  • Write up what it found, for a person who has to decide

It won't

  • Approve or decline funding
  • Move, release or schedule any money
  • Sign off an exception or a waiver
  • Change banking instructions
  • Overrule a finding, even if you ask it to

None of that is a setting somebody could turn on. Those tools do not exist on this server, and a test fails if anyone adds one.

Kept

  • Tool name, timing, and outcome per call
  • Every document you send, as you sent it, for 30 days
  • The arguments of each call and the answer it got back, for the same 30 days
  • A SHA-256 of submitted evidence
  • The engine's result for a few hours, then deleted. It quotes the amounts and names it verified.
  • For an extraction: each field's path, confidence, and source
  • Client name and a daily salted IP hash
  • Model token counts

Never kept

  • Raw IP addresses
  • Your name, your email, or any account — the server never asks

Two cautions, and the second one changed on 15 September 2026. Anyone holding the link can use this server, because it asks nobody to sign in. And the operator now keeps what you submit: the documents, the call, the answer. Counts outlive that window; the documents do not. Send the sample packages and your own documents. A customer's documents belong on a server that knows who is calling.

For developers

Command line

Claude Code

verified 2026-09-15 
claude mcp add --transport http plumbline https://mcp.plumbline.cloud/mcp

MCP Inspector

verified 2026-09-15 
npx @modelcontextprotocol/inspector --cli https://mcp.plumbline.cloud/mcp --transport http --method tools/list

Gemini CLI

gemini mcp add --transport http --scope user plumbline https://mcp.plumbline.cloud/mcp

The command writes the server into your settings, which we confirmed. Gemini CLI then refuses to start any MCP server from an untrusted folder, so the connection itself has not been captured — trust the folder first.

Tools
  • explain_verification_run Explain a run in plain language
  • get_evidence_requirements Get evidence requirements
  • get_review_artifact Get the review artifact for a run
  • get_verification_capabilities Get verification capabilities
  • get_verification_run Get the control trace for a run
  • verify_funding_package Verify a funding package

Transport is Streamable HTTP with no session. Sign-in is OAuth through Clerk with a Google account; every request carries a bearer token the server verifies before any tool runs. Evidence read from a document by a language model comes back labelled untrusted, carrying a confidence and a source for every field.

Limits
  • max_documents 10
  • max_total_bytes 26214400
  • max_pages 100
  • media_types application/pdf, image/png, image/jpeg, text/plain
  • max_lines 100
  • max_supporting_invoices 75

Per client: 60 calls per ten minutes. Over a limit, the server answers with a retry delay.