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

Annotations already declare readOnly=true, idempotent, non-destructive and closed-world, so the safety bar is low, yet the description still adds real behavioral context: results are ordered closing-soonest-first, capped at 10, and venues with unparsed or unheld hours are excluded rather than reported as closed. It also discloses that each venue mapUrl triggers a location prompt on the reader's own device and carries no position, which is exactly the kind of side-effect detail annotations cannot express.

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 core capability is front-loaded in the first sentence and the field-level detail is justified because no output schema exists. It is nevertheless dense to the point of sprawl, particularly the seasonalClosureRisk sentence, which restates exclusion from `places` twice and could be tightened without losing meaning.

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 carry the entire return contract, and it does: it names every response bucket (places, hoursUnknown, publishedHoursOnly, opensNext, seasonalClosureRisk, townScope, mapUrl), the per-row fields, the row cap, and the empty-result behavior. Nothing an agent needs to call this correctly or interpret the answer 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 coverage is 50%, with `town` well documented in-schema while `category` carries only an enum and no prose in either place. The description partly compensates by explaining that `town` is read in the asker's own words, that regions are answered across every hamlet, and that unrecognized names return empty rows with `didYouMean`; but the category parameter is never mapped to its enum values, leaving one of two parameters under-specified.

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 with scope: 'What is open in an East End town at this moment and until when', computed from verified hours against America/New_York. It also enumerates the venue categories covered, which lets an agent separate it from siblings like search_places (general lookup) and recently_closed (historical status) 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?

Usage context is implied rather than declared: 'at this moment' plus the category list tells an agent this is a real-time open/closed query, and the townScope notes explain how the place argument is read. However, no sibling is ever named and there is no explicit when-not guidance, so an agent must infer that static lookups belong in search_places and closed-venue questions in recently_closed.

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