Use Lowball in ChatGPT, Claude, Cursor and more

Paste a Zillow rental link into the chatbot you already use and get what similar rentals nearby ask, how long the listing has really been up, whether it has been cut, an offer, a likely settling point and a message to send. Lowball is a free MCP server. No account, no key.

https://api.lowball.rent/mcp

What you can ask

Three read-only tools answer those: check_rent takes a Zillow link, score_rental takes the numbers when there is no link, and renewal prices a renewal increase against nearby asks and what the landlord loses if you leave. The chatbot does the talking; Lowball supplies the numbers and the reasons.

Claude (claude.ai, desktop and mobile)

1. Open Customize, then Connectors.
2. Click + Add, then Add custom connector.
3. Name it Lowball and paste the server URL above. Click Continue.
4. Under Authentication choose No sign in, then Add.

Available on Free (one custom connector), Pro, Max, Team and Enterprise. On Team and Enterprise an owner adds it under Organization settings. Steps from Claude's help center, read 2026-11-04. Lowball is also listed in Claude's connector directory, so you can find it under Customize, Connectors by searching for Lowball instead of pasting the URL.

ChatGPT

1. Open Settings, then Apps (older accounts: Connectors), then Advanced settings, and turn on Developer mode.
2. Choose Create, name it Lowball, paste the server URL, authentication None.
3. Start a chat, open the tools menu and switch Lowball on.

Custom MCP servers need a paid ChatGPT plan; on Business and Enterprise the route is Plugins, the plus button, then Add custom MCP server. OpenAI changes these menus often. Lowball is also being submitted to the ChatGPT plugin directory, which will remove these steps.

Claude Code

claude mcp add --transport http lowball https://api.lowball.rent/mcp

Or install the plugin, which adds a skill that knows when to call each tool:

claude plugin marketplace add peterskotte123/lowball-plugin
claude plugin install lowball@lowball

Cursor

Add to Cursor

One-click install link in Cursor's documented format. If the button does nothing, open Cursor Settings, MCP, Add new MCP server, and paste the URL.

VS Code

code --add-mcp '{"name": "lowball", "type": "http", "url": "https://api.lowball.rent/mcp"}'

Or add it to mcp.json as an http server with that URL. Needs VS Code with Copilot agent mode.

Codex

codex mcp add lowball --url https://api.lowball.rent/mcp

In the Codex desktop app: Settings, MCP servers, Add server, choose Streamable HTTP and paste the URL.

Terminal, no chatbot at all

npx -y @lowball/mcp check https://www.zillow.com/homedetails/…_zpid/

The same tools as a command line (@lowball/mcp on npm). score and renewal take the numbers as flags; help lists them.

A Zillow rent checker as an MCP server

MCP (Model Context Protocol) is the open standard chat assistants use to call outside tools. Lowball's server is listed in the official MCP registry as io.github.peterskotte123/lowball, and clients that read the registry (Cursor, VS Code, Gemini CLI and others) can find it there. It is read-only: it never writes to Zillow, never signs in anywhere, and holds no Zillow credentials. When you paste a link, our own server fetches the listing's public facts, scores them, and returns the numbers with the reasons. The Zillow id is the only thing about the listing that is kept, under a one-way key; the chat itself never reaches us. Source and docs: the plugin repository.

Prefer a page to a chatbot? lowball.rent/check takes the same link, and the browser extension shows the same numbers on the Zillow page itself.

Questions

Is it free?

Yes. There is no account, no key and nothing to pay. The server answers any client that speaks MCP.

What does it send?

Only the Zillow listing id from the link you paste, or the rent, ZIP and bedroom count you type. No name, email or chat history reaches Lowball. Listing facts are fetched by our own server. See the privacy policy.

Does it work outside San Diego?

It works anywhere Zillow lists rentals. The model is trained on San Diego County and tracked nightly; elsewhere it builds the estimate from the listings it has seen nearby and says so with a wider range.

Is Lowball affiliated with Zillow?

No. Lowball is an independent product and is not affiliated with, endorsed by, or sponsored by Zillow Group, Inc. It reads the public listing you paste and nothing else.

Is the number a guarantee?

No. Every answer is an estimate from public listing data and ends with that line. Whether a landlord accepts is up to them.

Steps checked against each vendor's documentation on 2026-11-04. Estimates, not a guarantee.