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

Annotations already declare readOnly/idempotent/non-destructive hints. The description adds valuable context beyond these: returns elevation in meters relative to sea level, preserves input order, explains the sub_ice_topo option for bedrock topography, and states 'public domain, no auth required.' It also notes the data source (GEBCO WMS). No contradiction with 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?

The description is densely informative with no filler. It front-loads the core action and batch size, then explains return format, optional parameter behavior, and data provenance. Every sentence earns its place; the structure is logical and compact.

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 two-parameter batch elevation tool with rich annotations and an output schema present, the description covers all decision-relevant context: the exact input shape, the optional surface selection, return ordering and units, use case, data source, licensing, and authentication status. Nothing an agent needs to invoke this correctly 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 description coverage is 100%, so a baseline of 3 applies. The description adds meaning beyond the schema: it explains the semantics of the points array as a route/transect, clarifies that sub_ice_topo returns bedrock beneath ice sheets rather than the ice surface, and specifies units and ordering. This raises it above baseline.

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 a specific verb and resource: 'Get seafloor depth or land elevation for up to 15 latitude/longitude points in one call from the GEBCO global bathymetric grid.' It distinguishes itself from sibling gebco.elevation.point by emphasizing the multi-point profile use case (route/transect) and batch capability. The tool's purpose is unmistakable.

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 clear usage context: 'useful for building a depth/elevation profile along a route or transect (e.g. a shipping lane or hiking trail).' This implies when to use it over the single-point sibling, but it does not explicitly name the alternative or state when not to use the tool. Clear context with no exclusions merits a 4.

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