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

Goes well beyond the annotations (readOnly/openWorld/non-destructive) by disclosing BYO OpenTopography key requirements, an Enterprise key for commercial use, a mandatory TerraMCP Bearer key with a URL, and what the response contains (source data plus provenance, hydrological units normalised to SI). These are exactly the operational facts an agent cannot infer from annotations.

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-loaded with the core action and the bbox constraint, which is good. However 'TerraMCP is a Wrench AI service' is filler and the OpenTopography key requirement is effectively stated twice ('BYO OpenTopography key only' / 'your own OpenTopography key').

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?

No output schema exists, and the description compensates by describing the return ('source data and provenance') and the unit convention. Auth prerequisites, size limits and dataset options are all covered, leaving nothing critical unstated for a 2-parameter tool.

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 bbox ordering, the 100 km² cap and the dataset enum are already documented. The description largely restates these ('Supply WGS84 bbox [west,south,east,north] covering at most 100 km² and dataset'), adding little syntax or selection guidance beyond what the schema provides.

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?

Specific verb ('Get') plus a precisely bounded resource ('a bounded elevation GeoTIFF from OpenTopography'), scoped to a stated purpose ('terrain analysis'). It is unmistakably distinct from every sibling, none of which retrieve DEM rasters.

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?

States the triggering condition ('where an appropriate local DEM is unavailable') and routes the agent to an alternative for a specific region ('UK projects should prefer Defra 1 m LiDAR DTM'). Both when-to-use and when-to-use-something-else are explicit.

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