Comparables via MCP: Comparable Properties and Valuations in Your AI Assistant
The Casafari MCP Comparables server lets AI assistants like Claude, ChatGPT, and Cursor return comparable properties and an estimated price in one request. Calling comparables_get-comparables retrieves live listings, past sales and rentals, and official registry records where available, around a point, address, or Spanish cadastral reference. The Free plan provides 1,000 tokens for 30 days without a card, as outlined in the plans and tokens in the developer FAQ (October 2026).
What does the Comparables MCP server actually return?
It is a Tuesday evening, and you have a vendor instruction meeting at nine o’clock tomorrow morning. Instead of spending two hours searching across portals, compiling spreadsheets, and cross-referencing records, you enter a prompt into Claude Desktop: “Fetch comparables for a two-bedroom apartment in central Madrid.” Within seconds, twelve comparable properties appear, neatly categorised by evidence type alongside a calculated baseline estimate.
Behind this response lies a deduplicated, cleaned property graph covering residential and commercial properties for sale and rent across 16 countries (US: entering now, selected states, commercial real estate only, via Claro AI). Every property in the graph is recorded as a single entity with its complete price and status history (October 2026). The server separates the evidence into distinct tiers: live on-market listings (asking prices), historical sales and rentals tracked through the property graph, and official registry records where national regulations make them available.
Connecting your AI environment requires no API key copying. The server runs over Streamable HTTP with OAuth 2.1 sign-in in the browser; see CASAFARI MCP, property data for AI agents.
Asking price or registered price: why the label matters more than the number
To property professionals, mixing asking prices with completed sale prices is a fundamental methodological error. Consider the market contrast in the United Kingdom during late 2026: according to Rightmove’s House Price Index, the average asking price for newly listed homes was £371,015 in October 2026 (+1.0% monthly). Conversely, the UK House Price Index from HM Land Registry recorded an average completed sale price of £273,037 in August 2026 (+0.3% monthly).
These two figures reflect distinct datasets and different points in time. Asking prices indicate current vendor expectations and active market competition. Registered sale prices reflect completed transactions negotiated months earlier, subject to conveyancing lags. A similar dynamic governs rental markets between advertised rents and achieved lease terms.
For a surveyor or broker, unlabelled data risks conflating vendor optimism with settled market value. The RICS professional standard on comparable evidence emphasises that comparable evidence forms the foundation of valuation, but must be weighed using professional judgement rather than uncritical averaging. Surfacing explicit evidence tags for every row ensures you understand what selling price, fair market price and out-of-market price mean when evaluating a property’s true standing. This clarity demonstrates why transactional data belongs in every valuation.
Three ways to point at a home: a point, an address or a cadastral reference
The Comparables server accommodates three distinct input mechanisms to locate subject properties:
- Coordinates and radius: Ideal for development land, new-build schemes without assigned addresses, or rural parcels where geographic boundaries take precedence over street names.
- Street address: The standard query mode. The address is sent as the target point of the search, with a radius in kilometres around it; no location id is needed.
- Cadastral reference (Spain only): Directly queries the referencia catastral, anchoring the search precisely to the registered legal unit in the Spanish Catastro rather than a portal listing.
In fast-moving cross-border markets like Spain, precision matters. The Colegio de Registradores de España reported an average price of €2,445/m² for all housing across 2025 (+8% year-on-year), with second-hand properties reaching €2,240/m² (+9.9%). Furthermore, INE’s House Price Index for the second quarter of 2026 indicated an overall annual price increase of 12.2% (existing homes up 12.9%). In such an environment, obsolete or misidentified comparables significantly distort estimates. Understanding how a cadastral reference helps property valuations allows professionals to maintain rigorous accuracy.
How is the estimated price produced, and how far should a professional trust it?
The estimated value returned alongside comparable properties is an algorithmic starting point derived from selected market evidence, not a formal RICS Red Book valuation or mortgage assessment. To understand the underlying calculations and handling of anomalies, review how the estimated value is calculated.
Different stakeholders use this output according to their specific governance requirements:
- Estate agents and brokers: Require defensible listing figures to support vendor conversations and winning listing instructions.
- Valuers and surveyors: Require traceable, auditable comparable records to complement site inspection findings.
- Lenders and risk teams: Demand consistent, repeatable benchmarks across entire loan portfolios.
To maintain compliance with the RICS Valuation – Global Standards (effective 31 January 2025), professionals can instruct their AI assistant to disclose its reasoning: displaying selected comparables, filtering criteria, evidence dates, and adjusted weightings.
From comparables to a CMA report the client can read
Generating evidence is only half the task; presenting it clearly to clients completes the process. With the Comparables server connected, your AI assistant can aggregate market data, outline market trends, and draft narrative sections for a Comparative Market Analysis (CMA) report. You can review the step-by-step workflow in the CMA report for clients use case on developers.casafari.com (English).
When sending documents to vendors, maintaining explicit labels between asking and registered prices builds trust. Sellers regularly inspect portal listings; explaining why an active asking price differs from past transactional evidence avoids unrealistic expectations. For teams preferring ready-to-use branded PDFs, the Valuation & Market Study report on CASAFARI provides an immediate platform-based solution. Developers interested in custom integrations can reference the Comparables & Valuation developer documentation.
What it costs and how to connect in five minutes
Integrating property intelligence into your AI workspace requires minimal configuration. The Casafari MCP servers support a broad ecosystem of clients, including Claude (web, Desktop, mobile), ChatGPT (Developer mode), Claude Code, Cursor, VS Code, Codex CLI, Gemini CLI, and any compliant MCP client. For Claude Code there is a plugin and for Gemini CLI an extension, both in the public casafari-mcp repository on GitHub, alongside code samples in curl, Python and TypeScript.
Pricing structures are simple:
- Free plan: 1,000 tokens for 30 days, no credit card required.
- Agent plan: €49 per month billed annually, or €70 month-to-month (ex VAT).
- Custom plan: By contract, with prepaid credits for extra usage.
- Location Lookup calls carry zero token cost.
To get started, navigate to how to connect a Casafari MCP server. Add the server URL, https://platform.casafari.com/mcp/comparables, to your chosen client, complete the OAuth 2.1 browser authentication by choosing to sign in to the Casafari platform, and begin querying comparable data instantly.
Frequently asked questions
How do I get comparable properties from ChatGPT or Claude?
Add the Casafari MCP Comparables server as a custom connector in Claude or ChatGPT Developer mode, complete OAuth 2.1 sign-in in your browser, and request comparables around an address, a point, or a Spanish cadastral reference. The assistant executes the comparables_get-comparables tool to return active listings, historical transactions, registry records where available, and an estimated price. You can test this on the Free plan, which provides 1,000 tokens over 30 days without requiring a credit card, as detailed in the plans and tokens in the developer FAQ (October 2026).
What is the difference between an asking price and a registered sale price?
An asking price represents a seller’s initial listing ambition, whereas a registered sale price records the final completed transaction logged in official land registries after conveyancing. In the UK market, Rightmove recorded an average asking price for new listings of £371,015 in October 2026, whereas HM Land Registry reported an average completed sale price of £273,037 in August 2026. Because these datasets reflect different property mixes and timeframes, a structured comparables tool labels each evidence source explicitly to ensure accurate valuation analysis.
Can an AI assistant produce a CMA report for a client?
Yes, an AI assistant can compile comparable properties, summarise local pricing trends, and draft narrative sections for a Comparative Market Analysis (CMA) report. Property professionals review and approve the evidence before submitting the final document to clients. You can inspect the step-by-step guidance in the CMA report for clients use case on developers.casafari.com (English). For immediate branded PDF generation, the Valuation & Market Study report on CASAFARI provides an automated platform workflow.
What is a cadastral reference and can I value a property with it in Spain?
A cadastral reference (referencia catastral) is the official legal identifier assigned to real estate units by the Spanish Catastro. In Spain, the Comparables server accepts this identifier to anchor valuation queries directly to registered property units rather than portal listings. This capability is specific to Spain; properties in other jurisdictions require an address or coordinate point. Learn more about how a cadastral reference helps property valuations.
Is the estimated price a formal valuation?
No, the estimated price is an automated benchmark generated from selected market comparables and does not constitute a formal RICS Red Book or mortgage valuation. It serves as an analytical baseline that complements, rather than replaces, physical inspections and surveyor expertise. RICS standards emphasise that while comparable data underpins property appraisals, human market knowledge remains essential. Review how the estimated value is calculated for deeper methodology details.