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

Annotations already cover the safety profile (readOnlyHint=true, idempotentHint=true, destructiveHint=false, openWorldHint=false). The description adds useful behavior beyond them: results include the exchange each listing trades on, the base parameter reorders listings by currency, and unchecked listings are flagged. That last point is a meaningful disclosure about result trustworthiness; only the return shape/pagination is left unstated (and an output schema exists).

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-loaded with the core purpose and example, and every clause carries information. The prose is a bit run-on and parenthetical, but there is no filler sentence to cut.

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 two-parameter lookup with full schema coverage, annotations and an output schema, the description supplies the intent, the routing decision, and the notable result traits (exchange, unchecked status). Only pagination/result-count behavior is unspecified, a minor gap given the output schema.

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 would be 3, but the description adds real meaning beyond the schema: it clarifies that query accepts partial names and ISINs, and that base is an ordering preference ('puts the listings in that currency first') rather than just a display currency, which the schema's own text does not convey.

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+resource (finds a ticker) and enumerates the accepted input forms (name, partial ticker, ISIN) with a concrete example ('Vanguard total world' gives VT). It also names the sibling it is not (validate_symbols), so an agent can route without opening the 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?

Explicit when-to-use ('Use it first when a ticker is uncertain') and an explicit exclusion with the alternative named ('for a list of tickers already written down, validate_symbols'). Nothing is left to inference.

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