Find the cheapest dates

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

With no annotations, the description must disclose behavior, and it does: 'Runs one search per date, so keep ranges modest (a 14-day scan takes several minutes).' This reveals a key performance characteristic. However, it does not describe the output format or any other behavioral details, though as a search tool there are few side effects.

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 description is two sentences, front-loaded with the core action, then a performance caveat, then an explicit alternative. Every word contributes useful information with no redundancy.

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?

Given the tool's complexity (17 parameters, no output schema), the description gives a clear high-level purpose, a performance warning, and a usage boundary. It could describe the return format or key required parameters, but the core usage is well covered for an agent to select and invoke the tool correctly.

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 53%, so the schema already explains many parameters. The description adds context about range size and performance, which indirectly relates to startDate/endDate and maxDates, but it does not explain any specific parameter in detail beyond what the schema provides. It does not compensate significantly for the undocumented parameters.

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?

The description clearly states the tool's function: 'Scan a range of departure dates and report the cheapest fare on each,' using specific verbs and a resource. It also distinguishes from the sibling search_flights by explicitly directing users with single-date flexibility to that alternative.

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?

Explicit guidance is provided: 'For a single date with ±flexibility, use search_flights with flexDays instead.' This tells the agent when not to use this tool and names the alternative. It also advises keeping ranges modest due to the one-search-per-date behavior, giving practical usage constraints.

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