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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds real value by naming the data source convention ('FarOut miles') and the shape of the result, but says nothing about ordering, how 'nearest' is computed, or how results are bounded.

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?

A single front-loaded sentence that puts the input first and the output second, with no filler. Slight redundancy in restating the 0–2656.4 range already encoded in the schema limits it below a 5.

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 simple read-only point lookup with no output schema, the description covers the essential contract: what goes in, what comes back. The unaddressed limit parameter and the undefined notion of 'nearest' are minor gaps rather than blockers.

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 must compensate. It does explain that 'mile' uses FarOut mile convention (useful beyond the bare min/max in the schema), but the 'limit' parameter, which defaults to 4 and caps at 10, is never mentioned at all, leaving one of two parameters undocumented.

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 states a concrete verb+resource (look up what is at a given PCT trail mile) and enumerates the return contents (leg, nearest towns/passes/lakes). It is clear enough to distinguish from get_pct_leg and list_pct_points in spirit, but never names or contrasts those siblings explicitly.

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?

Usage is only implied: an agent with a PCT mile and a need for nearby features can infer this is the right tool. There is no explicit when-to-use, no statement of when to prefer get_pct_leg or list_pct_points instead, and no preconditions.

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