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

Beyond the annotations (which already declare readOnly, openWorld, non-idempotent, non-destructive), the description adds genuinely useful operational context: it is an authenticated router requiring the caller's own OpenTopography key, and commercial use needs an Enterprise key. It also discloses the return shape (normalised SI units plus source provenance). It stops short of describing coverage/rate limits or what happens on key failure, but this is solid added value.

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 with no padding, and the auth/licensing constraint is placed after the return statement. Slight waste in the leading 'TerraMCP authenticated router: dem_clip' fragment, which repeats the tool name instead of spending those words on purpose.

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 no output schema the description does partially cover returns, but for a geospatial clip tool with 0% schema coverage it omits the bbox convention, dataset selection rationale, output format/resolution/nodata handling, and coverage limits. An agent cannot call this confidently from the description alone.

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 0%, so the description carries the full burden for two parameters and adds nothing: the four-element bbox ordering (presumably minLon/minLat/maxLon/maxLat), its coordinate order, and the meaning/tradeoffs of the six dataset enum values (COP30, COP90, SRTMGL1, etc.) are all unexplained. Only a vague hint that output is 'normalised SI' indirectly touches on units.

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 opening clause 'TerraMCP authenticated router: dem_clip' largely restates the tool name rather than stating what it does; an agent must infer 'clip' means extracting DEM elevation data for a bounding box. The second sentence clarifies the return ('normalised SI data and source provenance'), which signals an elevation-data retrieval tool, but the specific verb+resource+scope is never stated outright and no sibling is distinguished.

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 no when-to-use guidance, no guidance on choosing this over siblings like usgs_daily or ea_hydro_series, and no indication of when to pick which dataset. The only usage-adjacent content is the key requirement ('BYO OpenTopography key only'), which is a prerequisite, not a routing rule.

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