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

Annotations already declare read-only, idempotent and closed-world, so the safety profile is covered. The description adds useful context that the data is public aggregate with no personal or account information, and it describes the returned values (percentile and top X%) in the absence of an output schema. It does not cover edge behavior such as out-of-range or unsupported country inputs.

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?

Front-loads the core operation in the first sentence, then supports it with examples and a privacy note. The three examples are slightly redundant but each illustrates a distinct case (country, single-amount, age-qualified).

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 three-parameter read-only lookup with no output schema, the description supplies the return values and the data provenance, which is the main missing piece in structured fields. Only edge-case behavior and sibling routing are left out.

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 schema already documents net_worth_usd, country (ISO alpha-2 or 'WORLD') and the optional age. The description's example 'is $200k good at 30 in the US' adds intuition about how age is used but no syntax or constraints beyond the schema. Baseline 3 applies.

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?

Opens with a specific verb and resource: given a net worth and country, return the wealth percentile and 'top X%'. The example queries make the direction of the lookup unambiguous, though it never names the sibling country_net_worth_thresholds, which appears to be the inverse operation.

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?

Three concrete example questions ('what percentile is $500k in Germany', 'is $1M a lot in Japan', 'is $200k good at 30 in the US') give clear situational guidance and implicitly show the age variant. There is no explicit when-not-to-use clause, and the agent must infer that threshold-style questions belong to a sibling.

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