RiskModels Benchmark Fit (active weights)

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

Annotations already declare readOnlyHint/destructiveHint=false, but the description goes well beyond them: it enumerates the returned metrics, clarifies that weights use end-of-day prices and holdings follow the latest filings, explains the 'common date' alignment, and discloses the $0.02 per call price. That is substantive behavioral context an agent cannot derive from the annotations.

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 use case and exclusion, then returns, then valid benchmark values, then price — a sensible information hierarchy. It is dense and long for a tool description, but each sentence carries concrete content, so little is wasted.

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?

There is no output schema, so the description takes on the burden of describing returns and does so (active share, RMS proxy, overlap, largest over/underweights). Combined with the enum breakdown and cost disclosure, an agent has everything needed to call this 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; the description exceeds it by decoding the benchmark enum (ff_own as the subject's own free-float-cap weights, the large/small style cells, and 'all' meaning every available benchmark) and by explaining the common-date alignment between subject and benchmark. It does not, however, explain the interaction of top with the subject/benchmark selection beyond what the schema states.

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 (compare) plus the exact resource (active share and largest active weights) for a named subject type (fund, 13F filer, ETF portfolio). It explicitly distinguishes itself from riskmodels_get_fund, riskmodels_get_filer and riskmodels_get_etf, so an agent can route without opening any 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?

Opens with the triggering condition ('Use when you want to compare...with a benchmark') and supplies an explicit negative case with named alternatives ('Not for the subject's own holdings — use riskmodels_get_fund/filer/etf'). Both when-to-use and when-not-to-use are covered.

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