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

Annotations already establish read-only, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description earns real credit on top of that by disclosing the aggregation sources (Resy, OpenTable, Tock, SevenRooms), the exactness of returning times, and the minute-level volatility of the data — meaningful operational context an agent planning a call would not get from the 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?

Three short sentences, front-loaded with the resource and scope, then the when-to-use trigger, then the volatility caveat. No filler, no repetition of the title, and each sentence carries distinct information.

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 does the work of indicating what comes back ('exact times') and how fresh it is, which is the key expectation to set for a live-availability tool. It stops short of describing result volume, whether results are ranked, or what an empty response means, but nothing required for a correct invocation is absent.

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%, so both parameters (city enum with default, limit cap of 50) are already fully documented in the schema. The description names the cities and the notion of 'right now' but adds no syntax, range, or defaulting details beyond what the schema provides, so the 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?

States a concrete verb-and-resource ('tables bookable right now') plus scope: four named cities and four booking platforms with exact times. It is clear which resource is returned, but it never contrasts itself with siblings like hardest_tables or last_table_spotted, and the phrase 'hardest restaurants' actively overlaps with hardest_tables, so an agent must infer the split.

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?

'Use this when someone asks what they can get tonight or this week' gives a clear triggering context, and 'changes by the minute' reinforces that this is for immediate/imminent availability rather than research. What is missing is the negative case: nothing says to prefer hardest_tables for background research or when_does_it_release for future drops.

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