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

Annotations already provide readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds valuable behavior beyond annotations: the data source (OpenStreetMap via Photon), the 10-candidate limit, OSM verification links, and the explicit pricing model with free tier.

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?

Four tight sentences that front-load the core function, then layer candidate limits, data source, verification mechanism, and pricing. Every sentence earns its place; no filler or redundancy with annotations.

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 simple two-parameter tool with no output schema, the description covers function, both invocation modes, data provenance, candidate limits, output verification, and cost. It does not detail the exact response structure, but the mention of 'city, state, country, postcode' and OSM links gives sufficient shape to the return value.

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 50%: the query parameter is documented in the schema, and the description echoes its dual-purpose format. The 'limit' parameter lacks a schema description, but the description's 'Up to 10 candidates' partially compensates by indicating the cap. This is adequate but not exceptional.

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?

The description states a specific verb+resource: 'Place name or address → coordinates' and 'lat,lon → the nearest address', covering both geocode and reverse geocode modes. It clearly distinguishes itself from the sibling list, none of which offer geocoding functionality.

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 explains the two usage modes with a clear arrow notation that maps directly to the query parameter format. It implies when to use (address lookup or coordinate reversal) but does not explicitly state exclusions or name alternative tools, though no siblings are plausible alternatives.

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