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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, so the safety profile is fully covered. The description adds a useful return-field list (description, directions, ADA access, etc.), which is valuable because there is no output schema, but it does not disclose rate limits, auth needs, or failure behavior. No contradiction with annotations.

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 sentences with no waste: the first states the core purpose, the second lists return contents and provides a concrete invocation example. The example earns its place by showing the exact parameter shape. Front-loaded and well-structured.

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 tool with strong annotations and full schema coverage, the description plus schema provides everything needed to call it correctly: the required ID, the optional API key, expected return fields, and a worked example. Because there is no output schema, the return-field list in the description is an important addition. Nothing critical is missing.

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 100%, so both facility_id and _apiKey are already documented in the schema. The description's example repeats the schema example and reinforces that facility_id is the lookup key, but it adds little semantic meaning beyond that. Baseline 3 is appropriate.

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 verb and resource: 'Get full details for a single Recreation.gov facility... by its FacilityID.' The 'single' qualifier clearly distinguishes it from search-oriented siblings like search_facilities and list_campsites. No ambiguity about what the tool does.

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?

The description implies usage: call it when you already have a FacilityID and need full details for one facility. However, it does not explicitly name alternatives like search_facilities for discovery, nor does it provide when-not-to-use guidance. The usage context is implicit rather than explicitly contrasted with siblings.

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