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

Annotations already declare readOnlyHint=true and openWorldHint=true, and the description adds non-obvious behavior the annotations cannot express: a $0.003 USDC charge per successful call via x402 on Base, Solana or Arc, with failed calls not billed. That billing/authorization detail is exactly the kind of context an agent needs before invoking. It does not discuss rate limits or result shape, but the output schema covers the latter.

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?

The core purpose is front-loaded, but the sentence is a single run-on with two long parenthetical field lists that read like column dumps rather than decision-relevant guidance. The pricing and sibling-routing sentences earn their place; the indicator enumerations could be tightened considerably.

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 read-only, open-world search with an output schema and fully documented parameters, the description supplies the missing pieces: data sources, field coverage, filter dimensions, sibling routing, and payment terms. Only the absence of any note on result ordering or how the two rankings are paired side by side leaves a small gap.

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%, so all five parameters (limit, country, theYear, arwuYear, university) are already documented with examples and defaults. The description only restates that name and country can be combined and years are selectable, adding mild AND/OR semantics but no format or interaction detail beyond the schema. Baseline 3 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?

States a specific verb ('search') plus the exact resources covered: ShanghaiRanking ARWU and THE World University Rankings, and enumerates the fields returned for each. It also names the two sibling tools it is not (search_shanghai_arwu_rankings, search_shanghai_gras_rankings), so an agent can distinguish it without opening a schema.

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?

'Search by university name and/or country; years selectable' gives clear selection semantics, and the two sibling tools are routed with explicit conditions ('when you need ... ARWU 2026 world university ranking', 'when you need ... Global Ranking of Academic Subjects'). It does not say when to prefer this dual-source pack over other ranking siblings such as search_leiden_ranking or search_fifa_team_rankings, so the exclusions are incomplete.

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