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

Goes well beyond the readOnly/openWorld/idempotent annotations: 404 semantics plus 'not charged', the OSM attribution obligation, the Photon source with Nominatim fallback, and the x402 USDC-on-Base payment model at $0.001 per successful call with a PaymentRequired object when unpaid. That is exactly the behavioral context an agent needs to call a paid, fallback-backed tool safely.

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?

Front-loads the trigger and the payload fields in the first sentence, then layers provider, error, legal and pricing details. Dense but nearly every clause is load-bearing; the pricing/attribution tail slightly crowds a single-sentence tool.

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 no output schema, the description enumerates the return shape (lat/lon, display name, country codes, admin hierarchy, street/house number, OSM ids, bounding box), and covers failure mode, cost and licensing. Nothing needed to invoke or interpret a result 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?

Only one parameter (q) and schema description coverage is 100%, so the schema already carries the meaning including the place/address aliases. The description adds no syntax, format, or example guidance for q beyond what the schema states, so the baseline of 3 applies.

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 ('Geocode place or address') and enumerates the returned fields (latitude, longitude, display name, country/countryCode, OSM ids, bounding box). It implicitly covers forward geocoding, but never names the near-identical siblings geocode_search or geocode_reverse, so an agent still has to guess which of the three to pick.

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?

'Use when an agent has a city, landmark or postal address and needs lat/lon for maps, weather, distance or logistics' gives a clear triggering condition and downstream use cases. No explicit exclusions or named alternatives are given, so the reverse-geocoding sibling is only implied.

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