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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds useful scope detail by naming external sources (source websites and the RVO/EP-Online registry) and the Dutch market limitation. It does not disclose behavior when neither identifier is supplied (both parameters are optional) or what happens for an unknown slug, leaving the failure modes unexplained.

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?

Two sentences, front-loaded with the payload inventory and then the identifier routing. The enumeration of return fields is dense but each item earns its place by telling the agent what it can rely on. Minor cost: the long first sentence is heavily packed and could be split for scanability.

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?

No output schema exists, so the description must carry the return contract and it does, listing the fact categories and source links. Combined with the annotation coverage and the identifier routing, an agent has enough to call this correctly and interpret the result. The only residual gap, error behavior, is secondary for a read-only lookup.

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 33%, with just the language enum documented. The description compensates well for the two undocumented identifiers by explaining where property_slug comes from and what listing_id is for. The language parameter is left to the schema, which is acceptable since the schema covers it.

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 the facts of one Dutch home') and then enumerates what those facts are: address, size, building, current listings with source links, history summary, and EP-Online energy label. This is clearly distinguishable from siblings like get_place_insights or search_listings, which operate on areas and result sets rather than a single property.

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 concrete routing guidance: pass property_slug from search_listings or resolve_place, or listing_id for a listing without a property page. The upstream tools that produce the identifier are named explicitly. It stops short of saying when to prefer this over get_place_insights or what to do if an agent has neither identifier.

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