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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds useful behavioral context: results are a snapshot, and a prior-year comparison is available only for SEC-registered firms. It says nothing about data freshness beyond the snapshot, rate limits, or auth requirements.

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?

Two sentences, front-loaded with the resource and scope, and every clause carries information. The first sentence is dense with nested parentheticals ('each with its definition', 'for SEC-registered firms (the history)'), which slows parsing but does not pad.

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 does the work of enumerating the returned figures (firms, AUM, accounts, size bands, fee types) and signaling a definition accompanies each. That is enough for an agent to call it correctly; minor gaps are data recency and result format.

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, but the description genuinely adds meaning: segment is clarified as narrowing to all/SEC/state-registered, and include_bd_affiliated is explained as pulling in wirehouses, broker-dealers and banks that AdvisorIQ lists separately. It also disambiguates that the year-earlier history applies only to the sec segment.

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 resource (aggregate RIA market figures: firm counts, AUM, accounts, size bands, fee types) and scope (US or one state), which is clearly distinct from siblings like search_ria_firms or ria_rankings. It never names those siblings, so an agent must infer the boundary between 'aggregate market stats' and 'rankings/search'.

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?

The description explains how to narrow results via scope and segment and what include_bd_affiliated toggles, which implies usage context. But it gives no explicit when-to-use/when-not guidance and never points to an alternative tool for firm-level rather than aggregate data, leaving the sibling boundary implicit.

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