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

With no annotations provided, the description carries the full burden of behavioral disclosure. It goes beyond a simple definition by explaining the consensus methodology (Cornish-Fisher + t-copula Monte-Carlo + filtered-historical-simulation, liquidity-adjusted) and clearly discloses the 1-day horizon limitation. It does not describe the exact return format, but the 'VaR + CVaR (USD)' phrasing gives some indication. No contradictions with annotations (none present).

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 three sentences with no filler. It front-loads the core purpose and scope, then adds methodology, usage guidance, and a critical caveat. Every sentence contributes distinct information, making it appropriately sized for the tool's complexity.

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's moderate complexity and lack of output schema, the description is fairly complete. It covers what the tool does, the calculation method, the specific portfolio context, and a key limitation. It could be more explicit about the shape of the return value (e.g., whether it returns both VaR and CVaR as separate numbers or a single value), but it does state the metrics and currency, making it mostly self-sufficient.

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?

Schema description coverage is 0%, so the description must compensate. It provides valuable clarity for the horizon_days parameter by explaining that multi-day is not scaled and only 1-day is served, despite the schema allowing up to 30. However, it does not explain the confidence parameter (e.g., what values mean, how it affects output), leaving a gap for this important parameter.

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 states the tool computes portfolio VaR + CVaR in USD on the live top-decile shadow book, with a specific call-to-action: 'Call this when the user asks how much the model portfolio could lose.' It distinguishes itself from siblings by focusing on portfolio-level risk rather than individual tickers or other metrics.

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 usage context: 'Call this when the user asks how much the model portfolio could lose.' It also warns about the 1-day horizon caveat, which is important for knowing when not to rely on it for multi-day horizons. However, it does not mention alternative tools (e.g., tengu_v2_var) or explicitly state exclusions beyond the horizon limitation.

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