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

Annotations already establish the safe read-only, idempotent, closed-world profile. The description adds real value beyond that: results contain category breakdowns and ranges, unsupported destinations behave differently, and figures are explicitly illustrative planning estimates rather than measured averages or supplier quotes — a meaningful accuracy caveat for a budgeting tool.

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?

Five tight sentences, each carrying distinct information (estimate method, destination vs country sourcing, return contents, unsupported handling, disclaimer) with the core purpose front-loaded. Dense but without filler, though the disclaimer and coverage sentences could be marginally tightened.

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 compensates by explaining what comes back (category breakdowns, ranges, coverage information for unsupported destinations). For a four-parameter, fully annotated read-only estimator, an agent has everything needed to call it correctly.

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 100%, so the baseline is 3, but the description adds the precedence relationship the schema only hints at: destination slug selects a destination-specific estimate, while country is the fallback when no slug is provided. It also reinforces that guest count and style tier are the estimate drivers.

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 (Estimates), resource (destination wedding budget), and the driving inputs (guest count and style tier). It is clearly distinguishable from adjacent estimators like get_alcohol_estimate or get_guest_travel_estimate.

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 effectively routes between input modes: a destination slug yields a destination-specific allowance, a country-only call yields a rough regional figure, and unsupported destinations return coverage info. It does not, however, explicitly compare itself to sibling estimators (alcohol, travel, who-pays), so the agent must infer when this tool is the right pick.

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