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

Annotations already declare readOnlyHint=false, idempotentHint=true, destructiveHint=false, so the bar is lower. The description adds real value beyond them: a privacy guarantee ('Nothing about the traveller is sent or kept') and the data-accuracy rule to report only first-hand traveller claims. Idempotency is left to annotations, which is acceptable.

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?

Three tight sentences that front-load the trigger condition, then the data-source rule, then the privacy note. Every sentence carries distinct information, with only mild overlap between 'Only report what the traveller told you' and the privacy clause.

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 write tool with an output schema absent but annotations covering safety and idempotency, the description supplies trigger, data-source discipline, and privacy behavior. Nothing essential to invoking it correctly 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?

With 100% schema coverage the baseline is 3, but the description adds cross-parameter meaning: check_id must come from a prior check_direct_price call, and 'its total when given' reinforces that total_paid is optional and conditionally supplied. This goes slightly beyond the schema's own text.

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 (report) and resource (whether a booking happened, and whether it was direct) and anchors it to the check_direct_price flow, so the agent can tell it apart from check_direct_price and report_hotel_price. No ambiguity about what the tool records.

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?

Gives an explicit trigger: 'When the traveller tells you they booked a hotel after a check_direct_price answer.' It also constrains the data source ('Only report what the traveller told you'). It doesn't name the sibling alternatives or when-not to call it, keeping it below a 5.

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