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

Annotations already cover readOnly/idempotent/openWorld/non-destructive, and the description adds genuinely new behavioral context: no authentication required, no AI narrative, unknown facts stay unknown rather than being defaulted, and the response can include coverage and commune-average limitations. It doesn't mention rate limits or estimate reliability beyond the caveat list.

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?

Three tight sentences: what it returns, the input policy, and the sibling alternative. No filler, and the most decision-relevant information (no account, numeric only) is front-loaded.

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?

Output schema and annotations are present, so return values and safety are covered elsewhere. But for a 32-parameter tool with almost no schema descriptions, the description leaves an agent under-equipped to supply the optional facts that drive estimate quality; the 'omitted facts stay unknown' policy is the only guidance.

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 6% across 32 parameters, so the description must carry the semantic load but provides only the general rule that omitted facts 'stay unknown.' It says nothing about which facts most affect the estimate, how commune/district/areaSqm interact, or the land vs. living-area distinction for areaSqm.

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 and resource ('Get a numeric Luxembourg property estimate') and immediately scopes it: no account, no AI-written report. It explicitly contrasts with the sibling get_price_estimate, so an agent can choose without opening either 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?

Gives a clear routing rule: use this for anonymous numeric estimates, use authenticated get_price_estimate for a full report. It also states the input policy ('supply explicit property facts; omitted facts stay unknown'), but doesn't cover other alternatives (e.g. get_listing_truth, get_market_context) or failure conditions.

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