India VIX (Volatility Index)

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds behavioral context: it returns latest value, daily change, and recent history, and explains the interpretation of rising/falling VIX. It doesn't contradict annotations and adds meaningful transparency.

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 two concise sentences, front-loading the core purpose and then adding interpretation and use case. Every sentence earns its place with no waste.

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 read-only tool, the description covers the essential information: what it returns and how to interpret it. It doesn't specify units, frequency, or data source, but these are minor and not critical for calling the tool. The description is adequate for an agent to use it correctly.

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 tool has zero parameters, so schema coverage is trivially 100%. Per the rubric, 0 parameters baselines at 4. The description doesn't need to elaborate on parameters; it adds value by describing the output semantics, which 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?

The description opens with 'Get the India VIX' – a specific verb and resource. It explains what the VIX is (expected near-term volatility, 'fear gauge') and what it returns (latest value, daily change, recent history). It clearly distinguishes this tool from the many siblings by focusing on the VIX index itself, not generic index history or performance.

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 explicitly states when to use it: 'Use for market-timing and risk context.' This provides clear usage context. It doesn't mention when not to use it or alternatives, but given its highly specific scope, the guidance is sufficient.

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