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

With no annotations, the description carries the full burden, and it does disclose real traits: schematic lines are flagged and are not GPS tracks, figures may be provisional, and null means 'not recorded'. It still omits the obvious read-only nature, error behavior for unknown slugs, and the response shape, and the permit-status paragraph reads as boilerplate copied from another tool rather than behavior of this one.

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?

Eight loose sentences with no grouping, mixing return-field semantics, citation advice, and permit-status vocabulary that may not even apply here. There is redundancy ('or null when the feed has none' immediately followed by 'Null means not recorded'), and only the first fragment 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?

With no annotations and no output schema, the description is the only source of return-value information, and it does cover the schematic flag, verifiedDate, and permit status. It is still incomplete: no GeoJSON structure, no error/empty-result behavior, and no signal about other fields the agent might encounter.

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?

One parameter with 0% schema description coverage, so the schema contributes nothing. The embedded URL template /trails/{slug}/geojson indirectly tells the agent that slug is the trail identifier, but there is no statement about format, uniqueness, or what happens if the slug is unknown.

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 phrase 'Trail line from /api/v1/trails/{slug}/geojson' signals that this returns the GeoJSON geometry for a trail identified by slug, which is specific enough to be understood. However it is a noun fragment rather than a verb+resource statement, and it never contrasts with the sibling get_trail, so an agent must infer the division of labor.

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 explicit when-to-use or when-not statement relative to get_trail, search_trails, or get_permit. The one routing hint is conditional and about a follow-up step ('A returned figure can be verified with get_provenance'), which implies when to reach for a sibling but not when to choose this tool.

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