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

Annotations already declare readOnlyHint=true and idempotentHint=true, covering the safety and idempotency profile. The description adds the resolution (~90m) and the data source (Copernicus DEM), which is useful context. However, it doesn't disclose potential error behavior (e.g., invalid coordinates, server limitations) or response structure, but the output schema likely covers the latter. Given annotations cover the main behavioral traits, a 3 is appropriate.

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?

The description is concise and well-structured: it states the core function, the resolution, the input format, a capacity limit, and practical use cases in two sentences. No wasted words, and key constraints (100 pairs) are front-loaded.

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 tool with a clear output schema (not shown but indicated), the description covers all necessary aspects: what it does, input constraints, capacity, and use cases. Minor gap: it doesn't mention what the output looks like (e.g., elevation values in meters), but the output schema likely covers that. Also, it doesn't mention coordinate validation or error cases, but these are less critical given the annotations.

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%, so each parameter is already documented with ranges, constraints, and their relationship (must be same length). The description adds the semantic context of 'coordinate pairs' and the limit of 100 pairs, but doesn't add much beyond the schema's constraints. Baseline 3 is correct since the schema does the heavy lifting.

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 purpose: retrieving terrain elevation from a specific model (Copernicus DEM) at ~90m resolution. It specifies the input (coordinate pairs) and distinguishes it from weather-focused siblings like openmeteo_get_forecast. The verb 'Get Elevation' is specific and resource-oriented.

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 provides a clear 'when to use' context: 'useful for geographic context, elevation-adjusted weather interpretation, or route planning.' It doesn't explicitly state when NOT to use it or list alternatives, but given the distinct purpose (elevation vs weather), the guidance is adequate. A slight gap is not mentioning that for weather queries, siblings like openmeteo_get_forecast should be used instead.

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