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

With no annotations, the description carries the full behavioral burden; it usefully discloses that 'no session or token is needed', which is real value. However, it doesn't say what happens if there is no prior search, whether the refinement is recorded or stateless server-side, or what the call returns, leaving meaningful behavioral gaps.

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 tight sentences: the action, the trigger examples, and the statelessness note. Front-loaded and every sentence earns its place with no filler.

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?

No output schema exists, so the description should hint at what comes back — the schema's previousIntent references a 'currentIntent object from the previous response', but the description never tells the agent the response carries that object, which is needed to chain refinements. Otherwise the essentials for invocation are present.

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%, so all four parameters including the optional persona and previousIntent are already documented in the schema. 'Send the original query plus the refinement' only restates the two required params without adding format or constraint detail beyond the schema.

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 (refine) and resource (a previous CielStay search) with concrete example refinements, so an agent immediately knows this is a follow-up operation. It implicitly separates itself from search_vacation_rentals by scoping to a 'previous' search, but never names the sibling explicitly.

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 clear triggering conditions with quoted guest utterances ('more rustic', 'closer to the park', 'bigger place'), which is strong when-to-use guidance. It stops short of stating when NOT to use it (e.g., for a brand-new search, use search_vacation_rentals instead).

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