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

Annotations already declare readOnlyHint, idempotentHint, closed-world and non-destructive, so the safety profile is covered. The description adds genuinely new behavioral context the annotations cannot convey: the data is a dated snapshot of Greca House's own listings at ASKING prices, not transaction prices, plus an anti-hallucination instruction. It stops short of richer detail (e.g. how stale the snapshot is, pagination), so 4 rather than 5.

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

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

Four dense sentences, front-loaded with the use case before the exclusions, and every sentence carries load (scope, provenance, exclusions, anti-hallucination rule). It is longer than typical but not padded, though the final 'other sources may be cited' sentence is slightly tangential to tool selection.

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

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

With an output schema present, the description need not explain return values; it instead supplies the things structured fields cannot — data provenance, snapshot nature, and scope boundaries versus forecasts and whole-market indices. An agent has everything needed to select and invoke it correctly.

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

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

Schema description coverage is only 50% (the topic enum has no per-value description), and the description compensates by spelling out the topics in prose: regional overview, Athens neighbourhood medians, budget windows, method, CSV downloads — mapping cleanly onto the enum values. The language parameter is left to the schema, which already documents it, so the description adds real but partial value.

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

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

The description names a specific resource (Greca House's own asking-price research on Greek property) and enumerates exactly what it returns: regional overview, Athens neighbourhood medians, budget windows, method, CSV downloads. It also states what it is NOT (a whole-market transaction-price index), which lets an agent separate it from sibling property tools without opening the schema.

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

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

Explicit when-to-use ('when the user asks for Greca House's research on Greek property asking prices') and explicit when-not-to-use (forecasts, predicted appreciation, next-year growth, time-series trends, whole-market future prices). It even rules out filling gaps from memory and sets a condition for citing other sources, which is unusually complete routing guidance.

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