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

With no annotations and no output schema, the description carries the full burden and delivers meaningful behavioral context: figures are sourced and dated, may be provisional, permit status is enumerated (verified-official, reported-secondary, unverified, or null), and null explicitly means 'not recorded.' It stops short of permissions, rate limits, or pagination, but the data-trust semantics are unusually well disclosed.

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 purpose is front-loaded, but the body drifts into a provenance lecture with redundancy ('Figures are sourced and dated. They may be provisional... This server does not invent figures'), consuming space that the undocumented input filters needed.

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 seven-parameter tool with no annotations and no output schema, the description details output trust signals but omits any guidance on the inputs an agent must actually supply. It is under-specified where the risk of a wrong call is highest.

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 only 14% (just sacScale), and the description explains none of the seven inputs — region, country, distance bounds, maxTypicalDays, or permitRequired. The word 'Filter' implies these exist but adds no meaning beyond the schema names, leaving the coverage gap unpatched.

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 opening sentence states a specific verb and resource: 'Filter trail summaries from /api/v1/trails.' This is a concrete operation, though it never distinguishes itself from the sibling get_trail, so an agent must infer that search_trails is the multi-criteria list while get_trail is the single-record fetch.

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?

There is no statement of when to use this search versus get_trail, get_geojson, or the list_* tools. The only routing hint is 'a returned figure can be verified with get_provenance,' which is post-hoc verification, not selection guidance for this tool.

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