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

Annotations already declare readOnly, idempotent, closed-world and non-destructive, so the safety profile is covered. The description adds useful context beyond them: the numbers are 'Gale Finance's published' figures sourced from a compare page, implying pre-computed third-party data rather than live computation. It does not mention staleness, update cadence, or behavior for unknown assets.

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?

A single front-loaded sentence naming the resource and scope, followed by a short usage example. The long metric enumeration partially duplicates what the output schema already conveys and could be trimmed, but it reads cleanly with no filler.

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?

The tool is simple in inputs (one required identifier) and has an output schema, so the description need not explain return values, and it nonetheless names the metric set. Complete enough to call correctly; the only real omission is sibling disambiguation against get_risk_return_metrics.

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?

There is a single required parameter with 100% schema description coverage that already lists accepted forms (ticker, name, alias with examples like 'BTC', 'silver'). The description adds no further meaning about accepted identifiers, ambiguity resolution, or failure behavior for unresolved assets, so the schema does all the work.

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 gives a specific verb+resource ('published downside risk for one asset') and enumerates the exact metric family: 5% daily VaR, expected shortfall, skew, excess kurtosis, drawdown episodes, 1Y max drawdown, best/worst day. It does not explicitly differentiate itself from the overlapping sibling get_risk_return_metrics, so the boundary between the two is left to inference.

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 only implied, mainly through the example question 'What are the tail risks for bitcoin?' There is no statement of when to prefer this over get_risk_return_metrics or compare_assets, and no exclusions or prerequisites, so an agent must guess at the sibling boundary.

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