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

Annotations already declare a safe read (readOnlyHint=true, destructiveHint=false), but the description adds substantial behavioral context beyond them: annual only, latest restated values, one table per axis, as-reported (never estimated), derived margin methodology, and a critical warning that rows can OVERLAP so users must not sum rows. This is exactly the kind of disclosure annotations cannot carry.

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?

Purpose is front-loaded and each clause carries real information (scope, derivation, overlap warning, alternative). However it is delivered as a single dense run-on paragraph with several embedded parentheticals, which hurts scannability slightly.

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 carries the full burden of describing return shape and it does so: one table per axis, a consolidated total row per table, raw member QNames, exact periods, and derived margins. Nothing an agent needs to call and interpret the tool is missing.

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 both parameters (ticker, maxYears) are fully documented in the schema. The description's mention of 'annual fiscal years only' loosely frames maxYears but adds no syntax or format 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+resource with precise scope: revenue disaggregated by business segment, geography and product/service, plus operating income by segment when tagged. It explicitly routes away from siblings GetFinancialStatement and GetFinancialFact, so an agent can distinguish this from adjacent financial tools 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?

Gives explicit when-to-use context (segment profitability and margins via issuer-tagged dimensional facts) and an explicit when-not/alternative ('For consolidated figures use GetFinancialStatement or GetFinancialFact'). The annual-fiscal-years-only constraint further narrows applicability.

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