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

With no annotations provided, the description carries the full behavioral burden and does disclose key traits: the result is a list of cheapest recent fares, one per origin city, sorted cheapest first, covering specified foreign regions and other Pakistani cities. It does not define 'recent', state data freshness, or describe pagination, but it conveys the core read-only query behavior and output ordering.

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 tightly written sentences with no wasted words. The core behavior and scope are front-loaded, and the second sentence provides efficient usage examples.

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 simple one-parameter schema, no annotations, and no output schema, the description adequately explains what the tool returns conceptually: cheapest recent fares per origin, sorted cheapest first. It leaves some gaps around data recency, result fields, and currency, but is complete enough 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 0%, so the description must compensate. It clarifies that the single required parameter is a Pakistani destination city and provides examples ('Lahore', 'Peshawar'), but it does not specify the expected format (e.g., city name vs. IATA code) or constraints beyond the examples.

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 resource (cheapest recent fare) and a clear scope (into one Pakistani city from each foreign region and other Pakistani cities). It distinguishes itself from generic fare tools by describing the inverted origin-to-destination aggregation, though it does not explicitly name or differentiate from siblings like search_fares or ticket_price.

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 concrete usage examples: 'cheapest way to fly home to Lahore' and 'which city abroad has the cheapest flights to Peshawar'. This makes the intended context clear, but it offers no explicit exclusions or guidance on when to use alternatives such as search_fares or cheapest_days instead.

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