finwire.pl - Polish financial data

Housing carry: rent vs mortgage interest per city

get_housing_carry

Read-onlyIdempotent

Carry nieruchomości finwire (finwire_housing_carry): per Polish city, the net rental yield of a typical 2-room flat (after one vacant month, flat-rate rental tax, admin fee in vacant months and property tax) minus the variable mortgage interest rate, in percentage points, monthly with history, plus net rent minus first-year interest in PLN per month for a loan covering the whole price. Negative carry = interest exceeds net rent; buying to let on credit then relies on price growth. For rents and plain yields use get_rents. Informational data, not investment advice.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "get_housing_carry"
  }
}

Input Schema

Name	Required	Description	Default
`city`	No	City name or slug (e.g. "Kraków" or "krakow") to get one city with its monthly history; omit for all cities.

Output Schema

Name	Required	Description	Default
`url`	Yes
`asOf`	No
`data`	No
`title`	Yes
`source`	Yes
`docsUrl`	Yes
`license`	Yes
`summary`	Yes
`citation`	Yes
`datasetId`	Yes
`sourceUrl`	No
`truncated`	No
`serverDate`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

AddedNov 4, 2026

TDQS

A4.4/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover read-only, idempotent, closed-world behavior, so the bar is low — and the description still adds substantial context: the exact cost deductions applied (one vacant month, flat-rate rental tax, admin fee in vacant months, property tax), the sign convention (negative carry = interest exceeds net rent), the monthly-history granularity, and an informational-not-advice disclaimer.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

It is front-loaded with the metric definition and the sibling pointer comes near the end, which is the right order. The long parenthetical of deductions is dense but each item is meaningful; only the repeated naming of the internal identifier (finwire_housing_carry) is mild redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given a single optional parameter, an output schema, and full annotation coverage, the definition supplies everything needed to decide when to call it and how to read the numbers, including the interpretation of negative values. Nothing material is missing for correct invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and the single `city` parameter already documents the name-or-slug format and the omit-for-all-cities behavior. The description adds only the general notion of per-city scope, so the baseline of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description names the exact metric (net rental yield minus variable mortgage interest rate, in percentage points, monthly with history) plus a secondary figure (net rent minus first-year interest in PLN/month for a full-price loan), scoped per Polish city. This is far more specific than the title and clearly distinguishes it from sibling housing tools like get_housing_prices or get_housing_costs.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It offers an explicit routing rule ("For rents and plain yields use get_rents") and frames the analysis context (buying to let on credit relying on price growth). It does not exclude or mention the other plausibly overlapping siblings such as get_housing_costs, get_housing_balance, or get_interest_rates, so the routing is helpful but not exhaustive.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

All finwire.pl - Polish financial data tools Inspect

Try in Browser

One endpoint for every MCP toolRayrun runs every MCP server behind one URL and holds the credentials. Each call is decided per client, tool, and argument, then recorded.ray.runAd

Glama MCP Gateway

Add one secure layer between your agents and this server.