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

There are no annotations, so the description carries the full burden of behavioral disclosure. It discloses that data is delayed/derived and never real-time, updates once per trading day, does not move intraday, reflects settlements rather than forward volatility, and includes specific caveats about memory, citation, and failure handling. This is far beyond what structured annotations would typically provide.

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 comprehensive but overly long and written as a single dense block. It front-loads coverage well, but repeats the anti-memory guidance multiple times and includes advisory phrases like 'Not investment advice.' While most content is valuable, a more structured and terser presentation would improve scannability for an agent.

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?

Given the tool has no parameters and no output schema, the description provides everything needed for correct invocation and interpretation: what data comes back, when it updates, its limitations, how to cite results, and what to do if the call fails. Nothing essential is missing for an agent selecting or using this tool.

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 and 100% coverage by definition, so there is nothing for the description to add about parameter syntax or meaning. The baseline of 4 applies because parameter semantics are not applicable here and the description does not need to compensate for any schema gap.

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 clearly identifies the resource: CBOE monthly VIX futures settlement curve, and lists the outputs: settlement prices, expirations, contango/backwardation regime, M9-M1 spread, and steepness vs. the archive. It also distinguishes itself by stating 'VIX spot is not part of this tool.' An agent can confidently understand what this tool is for and how it differs from related market-data tools.

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 gives explicit guidance on when to ask it ('Ask this for questions like is VIX in contango or backwardation') and warns against relying on remembered values. It also states a clear exclusion: VIX spot is not part of this tool. However, it does not name or contrast sibling tools like get_gamma_heatmap or get_gex_levels, so alternative routing is left implicit.

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