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

Annotations already declare read-only, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds genuinely non-structured context: benchmarks are identical for everyone, are never recommendations, and advice/customisation requests are refused. It does not describe pagination or result size, which keeps it from a 5.

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 identity of the resource, then filtering, then routing, then the refusal boundary. Dense but each clause earns its place; the family enumeration is slightly list-heavy but serves the 0%-coverage family parameter.

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 supplies a conceptual picture of what is returned (benchmarks grouped in families by stock share) and covers routing and refusal behavior. Pagination/ordering and the exact response shape remain unstated but are minor for a read-only list with zero required params.

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 0%, so the description must carry the load and largely does: it defines 'family' by listing its six values and defines 'band' by example (a name like 'moderate', a stock share like 60, or 'all stocks'). It does not state the exact accepted family strings verbatim or whether both filters combine, so it falls short of full compensation.

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 and resource ('list the ETFIQ benchmarks') and defines what a benchmark is (rules-based yardsticks over broad, low-cost ETFs, grouped in families). It explicitly distinguishes itself from get_benchmark ('then get_benchmark for one'), 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?

Gives an explicit trigger ('use when asked which benchmark measures a kind of model portfolio'), names the follow-up tool, and names the alternatives for adjacent intents (build_portfolio for custom portfolios). It also states exclusions: customisation/advice requests are refused.

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