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

Annotations already declare readOnly/idempotent/non-destructive/openWorld=false, so safety is covered. The description earns its keep by adding what annotations cannot: data provenance (OMI, Agenzia delle Entrate, ISTAT), temporal coverage including provisional 2025, and hard coverage limits (only 20 regions, only the 20 top-selling cities). It still says nothing about response shape, but with no output schema that is the main omission.

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?

A single sentence, front-loaded with the country marker 'ITALY.' and then the data definition. Every parenthetical (OMI register, provisional, ISTAT) carries provenance information that matters; there is no filler.

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?

For a one-optional-param lookup with no output schema and read-only annotations, the description supplies scope, years, granularity and source, which is close to sufficient. It omits the return shape and what happens for an out-of-scope place, minor but noticeable gaps.

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 coverage is 100% and the schema already defines 'place' with examples and the empty-string default, so the baseline is 3. The description adds genuine value beyond the schema by revealing that only 20 regions and the 20 highest-selling cities are served, which constrains what a valid 'place' value can be and warns against assuming arbitrary municipalities.

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?

States a specific verb+resource (home sales data for Italy) and pins down the exact scope: 2024/2025, 20 regions and top-20 cities. An agent knows immediately this is Italian residential transaction data, not prices or mortgage data. It never explicitly names a sibling (e.g. compare_regions_it, stats_marche) to disambiguate, so it stops short of a 5.

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?

The text describes content only; it gives no when-to-use condition, no prerequisite, and no alternative tool to prefer for regional comparison or price queries. With siblings like home_prices_us, house_prices_es and compare_regions_it in the same family, the absence of routing guidance is a real gap.

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