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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds meaningful behavioral context: it is historical, derived from realized forward volatility of cosine neighbours, and yields discrete regime labels. This explains what the tool computes and its limitations without contradicting 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?

The description is extremely concise: three sentences covering definition, derivation, categories, usage positioning, and tier requirement. Every sentence adds value and there is no filler or redundancy.

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 an output schema present and annotations covering safety, the description sufficiently explains the tool's purpose, methodology, and non-forecast nature. It also notes the PRO tier access requirement. Minor omissions like edge cases or return envelope details are likely covered by the output schema, so the description is nearly complete.

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?

The schema has one required parameter 'ticker' with no description (0% schema coverage). The description mentions 'a ticker's factor analogues,' which clarifies the parameter's purpose, but it doesn't specify ticker format, accepted values, or case sensitivity. It partially compensates for the schema gap but could be more explicit.

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?

The description precisely identifies the output as a volatility regime (calm/normal/stressed) for a ticker's factor analogues, including the derivation method. It explicitly distinguishes itself from a volatility forecast, which separates it from sibling tools like get_market_regime.

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 positions the tool as a risk-coherence/screening signal and explicitly states what it is not ('NOT a volatility forecast'), providing some usage context. However, it doesn't name alternative tools or give explicit when-to-use vs when-not-to-use guidance, so usage is implied rather than prescribed.

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