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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds the meaningful gating condition that deep links must be enabled, implying the tool may not return a link otherwise, but it says nothing about the return shape or the disabled-feature 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?

A single front-loaded sentence with no filler. It is efficient, though the dense jargon slightly reduces immediate comprehension.

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 3-parameter, read-only tool with a fully covered schema and annotations, most of what an agent needs is present. However, with no output schema, the description should say more about what the 'redirect card' actually contains and what happens when affiliate links are disabled.

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 fully documents trip_id, segment_id, and flight_number, including the optionality and the segment_id-vs-flight_number fallback. The description adds no parameter meaning beyond this, so baseline 3 is appropriate.

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 (Return) and resource (a redirect card for comparable flight search for a trip flight), and the 'flight' framing distinguishes it from siblings like train_booking_link and ground_transfer_booking_links. The jargon-heavy phrasing ('Tineo redirect card', 'comparable flight search') is less concrete than it could be, but the purpose is identifiable.

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 conditional 'when affiliate flight deep links are enabled' is a system precondition, not an agent-facing when-to-use rule. It gives no guidance on choosing this over train_booking_link, segment_booking_links, or trip_booking_links. Usage is only implied.

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