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

The annotations already declare readOnlyHint, openWorldHint, idempotentHint and destructiveHint=false, so safety is covered; the description earns credit for adding behavior the annotations cannot: a result cap of 8, the fields each result carries (id, open/close dates, results date, page), and the no-match behavior (returns a note). The only gap is that pagination or truncation semantics beyond the cap of 8 are not described, though the cap implies the tool does not paginate.

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?

Three compact sentences, front-loaded with the core action and scope, followed by usage routing and return behavior. Every clause carries information — even the parenthetical example list does real work by clarifying the breadth of lotteries covered.

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 output schema, the description must describe returns, and it does: up to 8 items, the specific fields, and the no-match note. Combined with annotations covering the safety profile and a fully documented single parameter, an agent has everything needed to call this correctly and interpret the response.

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 single 'query' parameter already carries examples ('the wave', 'half dome', 'middle fork salmon'). The description's 'by place or name' phrasing confirms the accepted input style but adds no new constraint, syntax, or format detail beyond the schema, so the baseline of 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 opens with a specific verb and resource ('Finds Recreation.gov's permit and campground lotteries') and narrows scope to those 'still open or coming up', then reinforces it with concrete examples (Half Dome, The Wave, Angels Landing). It explicitly separates itself from set_lottery_alarm, so an agent can distinguish it from the one sibling that sounds related.

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?

It names the workflow position ('For looking up a lottery before set_lottery_alarm') and rules out a misuse ('it sets nothing'), which is clear when-to-use and partial when-not guidance. It does not spell out edge cases such as what to do when a lottery is closed or already past, but the core routing decision is unambiguous.

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