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

Annotations already cover the safety profile (readOnly, idempotent, openWorld, non-destructive), and the description adds behavior beyond them: it returns the caller's max_sites_per_alert cap and per-zone site_count, warns that park-wide is the wrong size fallback, and clarifies zone-vs-site scope. That is genuinely useful operational context not derivable from structured fields.

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?

Front-loaded with the core purpose and routing rule, and the sentences each carry information. It is somewhat verbose though: the Sandbanks parenthetical and the beach/quiet-loop examples restate the same zone-vs-site point twice, which dilutes the otherwise tight structure.

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 an output schema present, the description correctly avoids explaining return values, yet still surfaces the one return detail an agent must act on (site caps and site_count for sizing a selection). Combined with the downstream routing to get_zone_map/list_zone_sites/create_alert, an agent has everything needed to call it correctly.

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?

There is a single parameter with 100% schema description coverage, so the schema already documents campground_id as coming from list_park_campgrounds. The description's 'pass the zone ids in campground_selections' refers to create_alert, not this tool's parameter, so it adds essentially no syntax or format meaning beyond the schema. 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 first sentence states the verb and resource implicitly (listing zones within a campground) and immediately frames the granularity distinction from list_park_campgrounds. An agent can distinguish this from the sibling list_park_campgrounds without reading either schema, and the concrete Sandbanks example makes the resource concrete.

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?

Explicit when-to-use ('Call this before create_alert whenever the user names a part of a park'), an explicit anti-pattern ('stopping at list_park_campgrounds can make a park look like a single undifferentiated site pool'), and named downstream alternatives (get_zone_map, list_zone_sites). This is the full when/when-not/alternatives set.

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