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

Annotations already cover readOnly, openWorld, idempotent, and non-destructive hints. The description adds useful behavioral context beyond that: it documents the return contents (elevation in metres, dataset name, snapped coordinates) and states MIT licence, no auth, and no upstream cost, which aligns with the openWorldHint.

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 sentences, each earning its place: what it does, dataset options, return value, and licensing/use cases. The essential information is front-loaded and there is no redundant filler.

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 an output schema present, safety annotations provided, and all parameters documented, the description still adds the key extras an agent needs: no-auth access, MIT licence, no upstream cost, and concrete use cases. Nothing critical for selecting and invoking this tool 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 each parameter already has a meaningful description. The description's dataset details (srtm90m default, aster30m for high-altitude) mostly mirror what the schema already states, so it adds only marginal semantic value beyond the structured schema. Baseline 3 is appropriate.

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 uses a specific verb 'Get' with a clear resource: land surface elevation for a single latitude/longitude coordinate. It explicitly scopes itself to 'single' points, which separates it from batch or profile siblings, and states the metric unit (metres above sea level).

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 use cases (terrain analysis, hiking route planning, flight-path clearance, GIS workflows) and implies single-point usage versus batch via 'single coordinate'. However, it does not explicitly name alternatives like opentopodata.elevation.batch or mention when NOT to use this tool, so it falls short of a 5.

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