MCP · Codex
UK property data from Codex
CLI, app and IDE. Point at the URL, then authenticate. Once connected, Codex can resolve any UK address, value it, read its sale and listing history, check its planning constraints and name its registered owner, and read the published indices for any area. 94 tools, 51 of them free, one read-only sign-in.
Developers building on the property data who want to explore it from the same tool they write code in, before they write a line against the REST API.
https://mcp.marketcode.ai/mcpSteps
How to connect Codex
- 01
Add the server from the terminal
One command registers the server; a second signs you in.
Terminalcodex mcp add marketcode --url https://mcp.marketcode.ai/mcp codex mcp login marketcode - 02
Or add it in the app
In the Codex app or IDE extension: Settings, MCP servers, Add server, Streamable HTTP, enter the URL, then Authenticate.
- 03
Ask, then read the request
Ask Codex to use a tool by name. When you want the same call in code, the tool page on this site shows the REST twin and a curl for it.
The same steps sit beside the other clients on the MCP page.
Prompts
Things to ask Codex once it is connected
- “Use address_resolve on "10 Downing Street SW1A 2AA", then property_summary and epc_certificates on the UPRN.”
- “Pull market_index_series for SE22 monthly since 2015 and print the last settled period and the forecast points.”
- “Call market_volume_series for district SE22 for 2025 and tell me where the provisional months start.”
Every MCP tool has a REST twin at the same price, so what you prototype in Codex ports to a request with an API key without changing the data.
The catalogue is public: Codex can list the tools before you sign in; calling one needs the sign-in.
Tools
Tools to try first
Resolve an address to a UPRN
address_resolve()Resolve free-text address to canonical record (UPRN for UK).
Property summary
property_summary()One-call summary of a property: what it is, what building it belongs to,
Full valuation with back-series
valuation_full()Full valuation block for a property: the value and its range, a monthly
House price index series
market_index_series()The published house-price INDEX for one postcode district or local authority: the level per month (base period = 100), the forecast tail flagged, and provenance saying how the index was built.
Planning designations at a location
planning_designations()Every planning designation affecting a location, in one call: conservation
Registered proprietors of a title
ownership_by_title()Registered proprietor(s) for an HMLR title number.
FAQ
Questions about MarketCode from Codex
Do I need an API key?
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No. MCP clients sign in with your MarketCode account over OAuth and receive a read-only token. API keys are for the REST API; pasting one into an MCP client does nothing useful and puts a secret where it does not belong.
What does it cost?
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The catalogue shows which tools are currently free. Priced tools charge fixed credits per successful call, the same as over REST, and a new account starts with free credits. Every tool page and the pricing page show the price; a failed call is not charged.
What can a connected assistant do to my account?
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Read property data and spend credits at the catalogue price. The scope is read-only property data; it cannot see or change your keys, billing or account, and you can revoke the connection in the Hub at any time.
Can I use the same account for the REST API?
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Yes. One account, one credit balance. Create an API key in the Hub for REST; the MCP connection uses OAuth and needs no key.
Also
Other clients
We'll connect Codex with you, on a real address.
Thirty minutes. You leave with the connection made and a question answered.