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

Annotations only carry the read-only/idempotent safety profile; the description carries everything else and adds substantially: closing-soonest ordering, up to 10 results, the hoursUnknown/publishedHoursOnly distinction, seasonally-held-out venues, and the crucial rule that townScope.recognized:false is a not-found rather than 'nothing is open'. That is real behavioral disclosure beyond 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?

The first sentence is properly front-loaded with purpose, but the body is a single ~280-word paragraph that repeats its warnings ('never present the list as everything', 'never let it end at nothing is open', 'name them as seasonal') and could be tightened considerably. The content is useful, but density is high enough that signal is diluted.

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 explain the return shape, and it does: closesAt/address/phone/source-with-verification-date per venue, ordering, the 10-result cap, plus opensNext, hoursUnknown, publishedHoursOnly, seasonalClosureRisk and townScope.recognized/didYouMean. An agent has everything needed to answer correctly in the edge cases.

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 only 50% and the enum carries no per-value description, but the prose enumerates the category coverage (restaurants, breakfast, nightlife, wine, wellness, hair salons, ice cream, farm stands, oyster farms), mapping 'salon' to hair salons and adding meaning the enum alone lacks. Region-vs-hamlet semantics are covered in the schema, so this is additive but not complete.

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+resource+scope: what is 'actually open' in a named East End town 'at this moment, and until when', computed against America/New_York. An agent can distinguish it from search_places, find_shops and things_to_do without opening any schema.

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?

Gives explicit trigger phrasing ('now, right now, still open, tonight, this late') and a strong when-not rationale ('you cannot know it, and the clock you would reason from is the wrong one'), plus how to handle the empty/short answer via opensNext. It never names a sibling tool as the alternative, so routing away from nearby lookups is left implicit.

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