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

Annotations cover the safety profile (readOnly, idempotent, non-destructive) but the description adds real behavioral context the agent couldn't infer: boundary behaviour near national borders is disclosed, and the licensing/attribution requirement (OSM ODbL 1.0, must show attribution line) is a genuine obligation. It also flags that Gemeinde/Kreis/Land come from the municipality's official key rather than nearest Kreis point, a subtle accuracy caveat.

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 purpose, then usage routing, then behavioral caveats in a compact block. Slightly dense with the licensing sentence appended, but every sentence earns its place and none is redundant.

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 read-only, no-output-schema tool, it covers purpose, alternatives, output contents, boundary caveat, and attribution obligation. Nothing an agent needs to call and correctly present results 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% with an enum on language, so baseline would be 3; the description adds meaning beyond the schema by warning that omitting language defaults to German and yields a wrong answer for English questions, and clarifying that place names/road numbers are never translated. This is actionable semantic guidance beyond the raw enum.

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 ('turns a coordinate into words') and enumerates the exact outputs (nearest address, settlement, motorway junction with distances, Gemeinde/Kreis/Land). It explicitly differentiates from siblings find_place, find_poi, find_address by stating 'this only goes coordinate to words'.

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 explicit when-to-use ('when you already HAVE a lat/lon and need to say where that is') and when-not ('Do NOT use to look up a place or address BY NAME'), naming the three alternative lookup tools. Nothing is left to inference.

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