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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds domain context (data reflects the 2021 walk, legs are resupply-to-resupply segments) but says nothing about error behavior for out-of-range legs or what happens if the leg is missing.

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 dense sentence that front-loads the scoping fact (26 legs, 2021) before listing contents. No filler, though the parenthetical clause makes it slightly heavy for one sentence.

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?

No output schema exists, so the description usefully enumerates what a leg record returns: FarOut miles, length, 2021 days and dates, and the covering page. For a one-parameter keyed lookup this is close to sufficient, with only edge-case behavior left unstated.

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% and the schema description already spells out 'Leg number, 1 (Campo) to 26 (Canada)' plus min/max bounds. The description's mention of '26 Pacific Crest Trail legs' reinforces the range but adds no syntax or meaning beyond the schema, so baseline 3 applies.

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 names the resource precisely – a PCT leg out of 26, walked in 2021, resupply-to-resupply – and enumerates the fields it carries. It lacks an explicit verb, but the noun-phrase framing makes the retrieval intent unambiguous and clearly distinct from list_pct_points and find_by_trail_mile.

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?

No guidance on when to pick this over find_by_trail_mile or list_pct_points, no prerequisite or exclusion conditions. The agent must infer from the name alone that this is a per-leg lookup keyed by leg number.

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