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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety and scope are covered. The description adds useful context: it discloses returned fields (what each stop carries, mailing advice, last-checked date), but says nothing about auth, rate limits, or pagination.

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 tight sentences: the first lists exactly what the tool returns, the second states the two lookup modes. No filler, and the value proposition is front-loaded.

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 read-only, zero-required-param lookup with no output schema, the description covers what's returned and how to query it. The only gap is the underspecified fromMile/toMile semantics that the schema leaves blank.

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 33%, with toMile and fromMile carrying no descriptions. The description clarifies that town accepts partial names and that mile filtering is a range search, partially compensating, but it leaves the mileage semantics (inclusive bounds, units) 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?

States a specific noun-resource (vegan resupply options at PCT towns/stores) with the exact data fields returned, distinguishing it from generic trail tools like list_pct_points or get_pct_leg.

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?

Explains the two access patterns (search by town name, or by mile range), which gives clear context for when to use it. It doesn't name an alternative sibling or state when not to use it, so it falls short of a 5.

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