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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is fully covered elsewhere. The description adds real value by explaining the metric's interpretation (rising VIX = fear), but leaves "recent history" undefined as to window length or granularity.

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?

Three short sentences, front-loaded with what the tool returns before the interpretive gloss. The fear-gauge explanation is arguably decorative for an agent but does aid interpretation, so it earns its place.

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 parameters and no output schema, the description carries the burden of describing the return, and it does so at a high level. The one gap is that "recent history" is unspecified in length and frequency, which an agent cannot resolve from the schema or annotations.

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 takes zero parameters, so there is nothing for the description to disambiguate — the baseline for a no-parameter tool. The description correctly implies a parameterless single-resource fetch.

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?

A specific verb (Get) plus a uniquely named resource (India VIX), with an explicit statement of what is returned: latest value, daily change, and recent history. It is clearly distinguishable from adjacent tools like get_option_iv_history or get_index_performance by resource, though it does not name a sibling to route against.

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?

"Use for market-timing and risk context" gives an implied usage context but no when-not guidance and no named alternatives. An agent knows roughly when this is relevant but gets no explicit disambiguation from other volatility or index tools.

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