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

Annotations already declare read-only, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds genuinely new behavioral context: a 90 m default sampling interval, an override mechanism, a 100-point return cap, and a per-sample quota cost that can hit the plan maximum per call.

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?

Three sentences, each earning its place: returns first, sampling default second, cost third. No output schema exists, so enumerating the returned fields is necessary rather than redundant.

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 correctly carries the return-value burden and adds the quota constraint. Remaining gaps are the truncation behavior above 100 points and the precedence rule between the two sampling parameters.

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 coverage is 100%, so the baseline is 3, and the description only partially goes beyond it by explaining that `samples` or `interval_m` replace the 90 m default. It does not clarify what happens if both are set simultaneously, nor how `samples` interacts with the 100-point cap.

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?

States a specific verb+resource (elevation profile) and scopes it to "a path of two or more points," which implicitly separates it from the sibling `elevation` tool for single points. It also enumerates exactly what is computed: distance, ascent, descent, lowest/highest point, and per-sample distance/height/lat/lon.

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 explains sampling defaults and the cost model ("each sample counts as one lookup, up to the plan maximum"), which tells the agent how to use it economically. However, there is no explicit when-to-use routing versus the `elevation` sibling, and no stated precedence when both `samples` and `interval_m` are supplied.

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