RentCast

RentCast APIを使用して、物件データ、評価額、市場統計にアクセスします。

ドキュメント

RentCast MCP Server

A Model Context Protocol (MCP) server for the RentCast API. It gives Claude Desktop, Claude Code, and other MCP clients access to US property records, value and rent estimates with comparables, sale and rental listings, and market statistics.

You need a RentCast API key. Create one on your RentCast API dashboard.

🚀 Quick Start

There are three ways to run the server:

Claude Desktop extension: one file, no terminal needed.
Local installation: clone the repo and point Claude Desktop or Claude Code at it.
Containerized deployment: run it as an HTTP server with Docker.

1. Claude Desktop Extension

Build the extension (or download rentcast-mcp.mcpb from a release):
```
npx @anthropic-ai/mcpb pack . rentcast-mcp.mcpb
```
Double-click rentcast-mcp.mcpb, or drag it into Claude Desktop's Settings > Extensions.
Enter your RentCast API key when prompted. Claude Desktop stores it as a sensitive setting.

The extension uses the MCPB uv server type: Claude Desktop installs the pinned dependencies from uv.lock on first launch, so you do not need Python installed yourself.

2. Local Installation

Install uv (recommended):

curl -LsSf https://astral.sh/uv/install.sh | sh

Clone this repository:

git clone https://github.com/robcerda/rentcast-mcp-server.git
cd rentcast-mcp-server

Install dependencies:

Using uv (recommended):
```
uv sync --locked
```
--locked installs exactly what uv.lock pins, verified against the hashes it records, and refuses to re-resolve.

Using pip:
```
pip install -r requirements-lock.txt --require-hashes
pip install -e . --no-deps
```
requirements-lock.txt is generated from uv.lock and pins every dependency with hashes, so the pip path installs the same set as the uv one. pip install -r requirements.txt still works and installs exactly the same set.
Set your API key. Create a .env file in the project root:
```
RENTCAST_API_KEY=your_api_key_here
```
Or pass it in the env block of the client configuration below.

Configure Claude Desktop: Add this to your Claude Desktop configuration file:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "RentCast": {
      "command": "/opt/homebrew/bin/uv",
      "args": [
        "run",
        "--locked",
        "--project",
        "/path/to/your/rentcast-mcp-server",
        "rentcast-mcp"
      ],
      "env": {
        "RENTCAST_API_KEY": "your_api_key_here"
      }
    }
  }
}

Important: Replace /path/to/your/rentcast-mcp-server with your actual path, and /opt/homebrew/bin/uv with the output of which uv.

Restart Claude Desktop after saving the configuration.

OR configure Claude Code:

claude mcp add rentcast -e RENTCAST_API_KEY=your_api_key_here -- \
  uv run --locked --project /path/to/your/rentcast-mcp-server rentcast-mcp

If installed via pip instead of uv, use:

{
  "command": "python",
  "args": ["/path/to/your/rentcast-mcp-server/src/rentcast_mcp_server/server.py"]
}

Configuration

Variable	Required	Description
`RENTCAST_SURROGATE_KEY`	No	A surrogate credential (`hsurr:...`) to send instead of the real key. Preferred over `RENTCAST_API_KEY` when set
`RENTCAST_API_KEY`	Yes, unless a surrogate is set	Your RentCast API key
`RENTCAST_SUPPRESS_LOGGING`	No	`true` asks RentCast not to log your queries and query parameters
`RENTCAST_MCP_TRANSPORT`	No	`stdio` (default), `streamable-http`, or `http`
`RENTCAST_MCP_HOST`	No	HTTP bind address (default `127.0.0.1`)
`RENTCAST_MCP_PORT`	No	HTTP port (default `8000`)
`RENTCAST_MCP_ALLOWED_HOSTS`	No	Extra `Host` values to accept over HTTP, comma-separated
`RENTCAST_MCP_ALLOWED_ORIGINS`	No	Extra browser `Origin` values to accept over HTTP, comma-separated

Each HTTP setting also has a command line flag: rentcast-mcp --help.

Surrogate credentials

If your environment issues a surrogate credential (a string starting with hsurr:) in place of the real API key, set it in RENTCAST_SURROGATE_KEY. The server sends it in the X-Api-Key header exactly as given, the same way it sends a real key, and uses RENTCAST_API_KEY only when no surrogate is set. A value in RENTCAST_SURROGATE_KEY that does not start with hsurr: stops the server with an error instead of falling back to the real key.

Containerized Deployment

docker build -t rentcast-mcp .
docker run --rm -p 8000:8000 -e RENTCAST_API_KEY=your_api_key_here rentcast-mcp

The image serves streamable HTTP on port 8000 at /mcp. Host and Origin validation stay on even when bound to 0.0.0.0, so a client reaching it by a public name needs that name allowed:

docker run --rm -p 8000:8000 \
  -e RENTCAST_API_KEY=your_api_key_here \
  -e RENTCAST_MCP_ALLOWED_HOSTS=mcp.example.com \
  rentcast-mcp

The HTTP transport has no authentication of its own. Anyone who can reach the port can spend your RentCast quota, so put it behind a VPN or an authenticating reverse proxy if it is reachable from outside your machine.

✨ Features

🏠 Property Records

Public records for 150M+ US properties: attributes, owner, tax assessments, sale history, and features. Look up one address, or search by city, state, zip code, or a radius around a point.

💰 Value and Rent Estimates

RentCast's automated valuation model returns a value or long-term rent estimate with a range and the comparable listings used to calculate it. Tune the comps with comp_count, max_radius and days_old, or override the subject property's attributes.

📋 Sale and Rental Listings

Active and inactive for-sale and long-term rental listings, with price, listing dates, agent and office details, and listing history.

📈 Market Statistics

Sale and rental statistics for any zip code: average, median, min and max price and rent, price per square foot, days on market, listing counts, breakdowns by property type and bedrooms, and monthly history.

🔍 Search Queries

Search tools accept RentCast's query syntax:

Multiple values with |: property_type="Condo|Townhouse", bedrooms="2|3"
Inclusive ranges with : and * for an open end: bedrooms="2:4", price="*:500000", year_built="2000:*"
Up to 500 results per request, paged with limit and offset. Set include_total_count to get the total number of matches.

🛠️ Available Tools

Tool	Description	RentCast endpoint
`search_properties`	Search property records	`/properties`
`get_random_properties`	Random sample of property records	`/properties/random`
`get_property`	One property record by id	`/properties/{id}`
`get_value_estimate`	Value estimate with comparable sales	`/avm/value`
`get_rent_estimate`	Long-term rent estimate with comparable rentals	`/avm/rent/long-term`
`search_sale_listings`	Search for-sale listings	`/listings/sale`
`get_sale_listing`	One sale listing by id	`/listings/sale/{id}`
`search_rental_listings`	Search long-term rental listings	`/listings/rental/long-term`
`get_rental_listing`	One rental listing by id	`/listings/rental/long-term/{id}`
`get_market_statistics`	Market statistics and history for a zip code	`/markets`

Search tools return {count, limit, offset, hasMore, results}, plus totalCount when requested.

Prompts: property_analysis (value, rent, comps and market for an address) and market_overview (a zip code's sale and rental market).

📝 Usage Examples

Value and Rent for an Address

What is 5500 Grand Lake Dr, San Antonio, TX 78244 worth, and what would it rent for?

Find Listings

Find 3 bedroom houses for sale under $500k in 78704 listed in the last 30 days

Rental Market Trends

Show rental market trends in ZIP code 90210 over the last year

Investment Analysis

Compare the gross rental yield of condos and single family homes for sale in 33131

🔧 Troubleshooting

`RentCast API error 401`

The API key is missing or invalid. Check RENTCAST_API_KEY, or re-enter the key in the extension settings.

`RentCast API error 403`

The key is restricted to other endpoints or IP addresses, or there is a billing issue. Check your API dashboard.

`RentCast API error 429`

RentCast allows 20 requests per second per key. The server retries rate limited requests with backoff before reporting this.

Empty search results

RentCast reports "no results" as an empty results list. city and state are case-sensitive, and property_type must match exactly, e.g. Single Family.

Server disconnects on startup

Check the client's MCP logs. The most common cause is a missing RENTCAST_API_KEY, which makes the server exit immediately.

Development

uv sync --locked --extra dev
uv run pytest
uv run ruff check .

The tests run against a fake RentCast API and never make real requests.

Running the server locally

uv run rentcast-mcp

To use the MCP Inspector:

uv run mcp dev src/rentcast_mcp_server/server.py

Updating dependencies

uv lock --upgrade-package <name>
uv export --frozen --no-emit-project --no-editable --no-dev \
  --format requirements-txt --output-file requirements-lock.txt

CI fails if uv.lock, requirements-lock.txt, and requirements.txt drift apart.

Building the extension

npx @anthropic-ai/mcpb validate manifest.json
npx @anthropic-ai/mcpb pack . rentcast-mcp.mcpb

.mcpbignore keeps tests, CI files and local environments out of the bundle. When you add or rename a tool, update the tools list in manifest.json; a test checks that it matches the server.

License

MIT