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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It does not state whether the tool is read-only, whether it computes or fetches data, or what operational constraints apply. 'Bundle tier' hints at access level but does not explain behavior.

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 a single compact line with no filler. The opening label 'VRP Divergence Index' immediately communicates the core concept. 'Bundle tier' is cryptic but does not bloat the text.

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?

For a zero-parameter tool with an output schema available, the description provides the essential metric definition needed to select and invoke the tool. It could add interpretation or eligibility context, but the minimal invocation surface makes this largely 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 input schema has zero parameters, so there is nothing for the description to clarify. Baseline 4 for zero-parameter tools is appropriate; the metric definition is sufficient.

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 states a specific metric, 'VRP Divergence Index', and defines it as 'ATM straddle IV vs realized variance', which clearly identifies the tool's purpose. It is distinguishable from the sibling set by naming a distinct volatility-risk-premium concept, though 'Bundle tier' adds little clarity.

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?

Usage is implied by the metric definition: an agent would select this when it needs the VRP divergence index. However, the description does not explicitly say when to prefer it over related siblings such as get_rv_regime or get_premium_compression_data, nor does it give exclusions.

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