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

With no annotations, the description carries the transparency burden. It discloses that results are price-sorted and include dates, airlines, and price insights, but it does not mention parameter dependencies (e.g., needing at least one of departure/arrival) or potential error conditions, which are relevant for a tool with zero required parameters.

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 primary purpose and a concise summary of return content. Every word 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?

The description covers the output shape but leaves critical gaps: all parameters are optional in the schema, yet the description does not clarify if any are needed or how defaults work. There is no guidance on parameter interactions (e.g., departure/arrival requirements), and sibling differentiation is absent. Without an output schema or annotations, this is insufficient for full agent decision-making.

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?

The input schema covers all 5 parameters with descriptions, so the description need not repeat them. The description adds no extra semantic detail about parameters like month format or IATA codes, 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?

The description clearly states the tool's function: 'Find the cheapest flights across a full month.' This specifies the action (find cheapest flights), the resource (flights), and the scope (full month), and it distinguishes from siblings like flight_search or one_way_search by emphasizing month-wide, price-optimized search.

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 implies usage for month-wide cheapest-flight searches but provides no explicit when-to-use or exclusions. It does not name alternatives like flight_search or price_calendar, so the agent must infer when this tool is the right choice.

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