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

Annotations already cover read-only, idempotent, non-destructive and open-world, but the description adds genuinely non-obvious behavior: a secondary lookup of the same flight number on the previous day triggered only under a delay threshold, and that the response includes questions bearing on compensation eligibility. It does not mention auth needs, rate limits, or what happens when no record is found, keeping it short of a 5.

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 dense but front-loaded sentence leading with verb, resource and keys, then the conditional behavior, closed by a one-word 'Read-only.' qualifier. No filler and every clause conveys distinct information.

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 no output schema and only two parameters, the description compensates well by enumerating the returned fields and the conditional previous-day check. It leaves open the boundary case of what is returned for delays of three hours or more, and what an empty result looks like.

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 parameters are already documented with format examples in the schema. The description only restates them ('by flight number and scheduled departure date') without adding constraints such as whether dates must be in the past or timezone handling for the date. Baseline 3 applies when the schema does the heavy lifting.

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 ('Looks up a flight's record') plus the two lookup keys and enumerates the returned fields (route, airline, times, delay, status). It never names the sibling tool check_flight_compensation, so an agent can't tell from this description alone which of the two to call first for a compensation question.

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 context is implied rather than stated: the read-only record lookup is described, and a conditional branch ('when the record shows the flight on time or under three hours late...') is disclosed. There is no explicit when-to-use, when-not-to-use, or pointer to check_flight_compensation / get_claim_link as alternatives.

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