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Estimate fair value of a Singapore HDB resale flat

hdb_fair_value

Indicative price range (SGD) for an HDB resale flat, computed from recent registered resale transactions (data.gov.sg, Singapore Open Data Licence). Returns an estimate, a 25th-75th percentile range, the most similar recent sales, and notes. No token needed. Backtest: median error about 5% on unseen sales, versus about 9% for a plain town-and-type median. A statistical estimate, not a valuation. Free tier: 30 calls per caller per day.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "town": "<town>",
      "flatType": "<flatType>"
    },
    "name": "hdb_fair_value"
  }
}

Input Schema

Name	Required	Description
`town`	Yes	HDB town, e.g. "TAMPINES", "BISHAN", "ANG MO KIO".
`storey`	No	Floor number of the flat.
`flatType`	Yes	e.g. "4 ROOM", "5 ROOM", "EXECUTIVE".
`floorAreaSqm`	No	Floor area in square metres.
`remainingLeaseYears`	No	Remaining lease in years.

Schema Changelog

Changes observed during successful MCP inspections.

AddedNov 7, 2026

TDQS

A4/5.0

Behavior4/5

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

With no annotations, the description carries the full burden and does a lot: it discloses the data source and licence, states no token is needed, gives a backtest accuracy figure (about 5% median error versus about 9% for a plain town-and-type median), and states a free-tier rate limit of 30 calls per caller per day. It does not describe failure behaviour (e.g. what happens when a town/type combination has too few transactions), which keeps it below a 5.

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?

Front-loaded with the core purpose and return values, then supporting facts (source, auth, accuracy, limits) each of which earns its place. Slightly dense and fragmented into short clauses, but there is no filler and nothing important is buried.

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?

There is no output schema and no annotations, so the description has to cover return shape, accuracy expectations, access requirements, and limits – and it covers all four. The explicit 'estimate, not a valuation' caveat is exactly the context an agent needs to present results responsibly.

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%, so all five parameters already carry their own meanings and examples in the schema. The description adds nothing per-parameter beyond referencing recent transactions and the town-and-type baseline. Baseline 3 is appropriate when the schema does the heavy lifting.

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?

States a specific resource and scope up front: an indicative SGD price range for an HDB resale flat, computed from registered resale transactions. The description also lists the returned artifacts (estimate, 25th-75th percentile range, comparable sales, notes), so an agent knows exactly what it gets. None of the sibling tools overlap, so no sibling differentiation is needed.

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

Usage Guidelines3/5

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

The line 'A statistical estimate, not a valuation' is useful context for when it is appropriate and how to frame the answer, and 'No token needed' removes an auth worry. However, there is no explicit when-to-use / when-not-to-use guidance, and no requirements such as whether town and flatType must be canonical HDB spellings. Usage is implied rather than instructed.

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

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