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

With no annotations provided, the description carries the behavioral burden. It usefully discloses that this is an overlay rather than a trigger and identifies the data source, but it does not mention update cadence, whether values are delayed, or how the output is structured. The provided output schema partially compensates.

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 short phrases with no filler. It front-loads the instrument list and immediately follows with the key usage caveat, making every word earn 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?

For a zero-parameter tool with an output schema, the description is nearly complete: it names the assets, labels the use case, and sets the 'not a trigger' boundary. It could add a sentence on data freshness or intended pairing with other tools, but nothing essential is missing for correct invocation.

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 the schema fully documents the input surface and the description adds no parameter-level detail. This is the appropriate baseline for a no-parameter tool.

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 names the exact instruments (VIX, 10Y/TNX, dollar/UUP) and states the tool's role as a 'risk-tone overlay'. This distinguishes it from sibling market tools like get_fear_greed or get_macro_events, though it lacks an explicit verb such as 'retrieves' or 'returns'.

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 phrase 'Risk-tone overlay — not a trigger' clearly tells the agent to use this as background context rather than as a standalone alert or entry signal. It does not name alternative tools, such as get_latest_alert, but the exclusion is explicit and actionable.

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