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

With no annotations, the description carries the burden. It adds the output unit ('metres') and tier availability, which are useful. However, it does not disclose potential errors, coordinate bounds, or data source details, which would be expected for a tool with no annotation support.

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, no redundant phrasing, and the key action is front-loaded. Every word contributes meaning, from the verb to the coordinate qualifier to the access note.

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?

The tool is a simple single-point elevation query, with a rich schema (100% param descriptions) and an output schema available. The description sufficiently covers purpose, scope, and accessibility, making it complete for decision-making. It lacks explicit when-to-use guidance, but that is covered under usage guidelines.

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 description coverage is 100%, with each parameter (lat, lon, dataset_id) already described. The description adds no additional parameter meaning beyond what the schema provides, so the baseline of 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 clearly states the tool's function: 'Get the elevation in metres at a specific lat/lon coordinate.' It uses a specific verb ('Get'), identifies the resource (elevation), and specifies the scope ('specific lat/lon'), distinguishing it from siblings like Batch, Chart, and Stats.

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 implies usage for a single-point query via 'specific lat/lon coordinate,' contrasting with batch/statistical siblings, but it does not explicitly state when to use this tool versus alternatives or any exclusions. The tier availability note ('Available on all tiers including Free') is a constraint, not a usage guideline.

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