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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=false, and destructiveHint=false, fully covering the safety profile. The description adds the return-content context (fee, wait/endorsement, failure rate, expected cost) and a credibility signal ('with sources'), which is useful but not deep behavioral disclosure. No contradiction with annotations.

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 sentence that front-loads the core concept ('The concrete cost of failing an FAA knowledge test') before enumerating the delivered data points. Every clause carries information — fee, retest requirement, failure rate, expected cost — with zero filler.

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 single-parameter tool with no output schema, the description compensates by enumerating the return fields (fee per attempt, wait/endorsement, failure rate, expected cost), effectively standing in for an output schema. Given the simple input and full annotation coverage of the safety profile, nothing critical is missing for a correct call.

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% — the exam parameter is fully documented with all five enum values and their expansions (part107, ppl, ifr, cpl, atp). The description adds no parameter-specific detail beyond what the schema already provides, so the baseline of 3 for full schema coverage 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?

The description states a specific resource ('concrete cost of failing an FAA knowledge test') and enumerates the exact content delivered: fee per attempt, mandatory wait/endorsement, 2025 national failure rate, and expected failure cost. This precision distinguishes it from siblings like exam_facts (general facts) and compare_prep_options (prep product comparison), which cover different aspects of FAA tests.

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 content — the agent would call this when a user asks about the cost of failing an FAA test. However, the description never names a sibling or states when NOT to use it, nor does it route the agent away from exam_facts, which could plausibly cover similar ground. No explicit exclusions or alternates are given.

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