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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so safety is covered. The description adds real behavioral value beyond that: prices are in SAR, results are ordered with the airline's own booking link first, a partner link appears only when available, and the transaction completes off-tool.

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?

Front-loaded with the core action and constraints, and every English sentence earns its place. The Arabic sentence is a near-complete restatement rather than new information, which costs a little density but serves a bilingual audience.

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?

For a read-only search with no output schema, the description supplies what an agent needs: the search axes, the currency, the link ordering and the fact that payment is external. It stops short of noting result limits or empty-result behavior, but nothing critical is missing.

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 both the origin/destination format and the date formats are already documented in the schema. The description's only added semantic is the geographic constraint ('Saudi city names or IATA codes'), which is marginal against a fully covered schema — baseline 3.

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 and resource — 'Find the cheapest flights between two cities' — plus the distinguishing scope ('cheapest', 'between two cities'), which cleanly separates it from search_hotels, search_restaurants, and search_souq.

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?

Usage is implied by the input shape (origin/destination/departure), and the description sets a boundary by noting that booking and payment happen on the airline site. But it names no alternatives or when-not conditions, even though compare_prices is a sibling that could overlap with 'cheapest flights'.

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