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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, covering the safety profile. The description adds useful context about NDC compatibility and the unique charter inventory, but does not disclose operational details such as response format, rate limits, or search completeness behavior.

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 three short sentences with no wasted words. It front-loads the core function, adds differentiating inventory context, and closes with the expected outcome of finding the best available flight deals.

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 17 parameters and no output schema, the description provides the core purpose and data-source differentiator but does not explain result structure, pagination, or what constitutes a valid minimal query. The schema covers parameters well, but the description alone does not fully equip an agent to understand all behavior of a complex search tool.

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 the schema already documents every parameter. The description adds no parameter-level detail beyond a generic reference to 'search criteria', which is appropriate for the baseline but provides no additional semantic value.

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 states a specific verb and resource: a flight search API for flights only from Finland. It also distinguishes itself from the sibling search_holidays by emphasizing 'vain lennot' (flights only) and by highlighting charter inventory not available on other travel search engines.

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?

The description gives clear context for when to use the tool: when searching for flights, especially charter flight seats not found on mainstream search engines. It does not explicitly name an alternative or state 'use search_holidays for holiday packages', but the 'vain lennot' phrasing strongly implies the boundary.

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