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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower. The description adds genuinely new behavior: the quote_id expires after 30 minutes and ties into the booking flow, and results differ in nature depending on whether date/time are present.

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?

Two compact sentences with zero filler, and the primary behavior (fixed fare) is front-loaded before the input-dependent distinction. Nothing is repeated from the title or schema.

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, the description carries the return-value burden and does name the two key outputs (fare and quote_id). For a 6-parameter read tool this is nearly sufficient; only edge behavior around optional passenger/suitcase counts is left implicit.

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 coverage is 67%, so the schema already documents pickup_id, destination_id, date and time formats. The description adds meaning about how date, time, passengers and suitcases jointly produce an exact fare, but says nothing about what happens when passengers/suitcases are omitted or how they change the price beyond their inclusion in the exact-fare case.

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?

"Fixed fare for a trip" names the resource and the returned artifact (fare), and the two sentences make the exact-quote vs 'from'-price distinction explicit. It does not name a sibling tool to contrast with (e.g. suggest_pickup_time or check_flight), so it falls short of full sibling differentiation.

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 clearly conditions usage on inputs: supply date+time for an exact fare and a bookable quote_id, omit them for a typical daytime starting price. That is actionable context, though it never states exclusions or which sibling to use instead (e.g. when to use suggest_pickup_time to obtain the time).

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