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

Annotations already cover readOnly, idempotent, non-destructive and closed-world, so the bar is lower; the description still adds real value by disclosing the return shape ("the 5 closest examples with their query and a link") and the quota behavior ("Free: it does not count as a request"). What remains unstated is how "closest" relevance is determined or what happens when no examples match.

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, both front-loaded: the identity of the tool first, then the input/output contract. The example list is compact and each example maps to a distinct query pattern, so no sentence is wasted.

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 single-parameter, read-only lookup tool with no output schema, the description supplies everything needed: what it searches, what to pass, what comes back, and that it costs nothing against quota. Nothing an agent needs in order to call it correctly is missing.

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 describes topic as "what the query should find, in a few English words." The description goes beyond that by giving four concrete example topics and the "in a few words" format expectation, which helps the agent phrase a good input rather than just understand the field.

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?

"Searches the cookbook of overpass.ch: Overpass queries that were tested on the full planet" gives a specific verb (searches) and resource (a curated example-query cookbook), and the contrast with executing queries is implicit in the wording. It does not name the sibling overpass_query explicitly, so the differentiation from that tool is left to inference rather than stated.

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 description gives concrete sample topics ("bakeries in a city", "hiking routes", "count buildings", "changes since a date") that show what kinds of inputs this tool is meant for, and notes it is free, nudging the agent to try it before composing a query. It stops short of explicitly saying "use this before calling overpass_query" or stating when-not to use it.

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