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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered and the bar is lower. The description adds the field set returned, but with a dedicated output schema present, that is largely redundant and no additional behavioral context (caching, freshness, error on unknown id) is disclosed.

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?

Two sentences, zero waste. The core purpose is front-loaded ahead of the routing guidance, which is exactly the right ordering for a lookup tool.

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?

For a simple one-param read tool with an output schema, the description covers purpose and sibling routing sufficiently; the return shape is handled by the schema. Only the precondition for obtaining a restaurant_id is left implicit.

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 description coverage is 100% and the single parameter (restaurant_id) is documented in the schema, so the baseline is 3. The description adds no format, provenance, or sourcing guidance for the id beyond what the schema already says.

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 ('Fetch') and resource ('Resy restaurant profile') and enumerates the fields returned (name, cuisine, price, rating, address, contact, description). It also names the sibling tools it is not, so an agent can distinguish it from resy_search and resy_availability without opening a 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?

Explicitly routes the agent: resy_search to find a restaurant, resy_availability for bookable times, resy_locations to browse locations. Clear context for when each alternative applies, though it does not explicitly state the precondition (that you must already hold a restaurant_id from a prior search).

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