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

Annotations already cover safety (readOnly, non-destructive, idempotent, closed-world), so the bar is lower. The description adds useful behavioral context: it only produces output when foreign-currency holdings exist, and that base must be correct. It does not describe the output shape or comparison methodology beyond the hedged baseline, but that is partly covered by the output schema.

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 front-loaded with the core purpose, then usage conditions, then a prerequisite. It is compact and every sentence adds value. Minor redundancy in 'what exchange-rate moves added to its growth, volatility and worst fall' could be tightened, but overall efficient.

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 two parameters with full schema coverage, a nested holdings object, an output schema, and extensive annotations, the description covers purpose, when to use, and a critical prerequisite. The only gap is that it doesn't explicitly state that the tool returns a comparison (e.g., metrics with and without hedging), but the purpose sentence implies it.

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 coverage is 100%, and both parameters have detailed schema descriptions (base currency, holdings format, weights/amounts, ticker conventions). The description adds a note that base must be the holder's currency to be meaningful, which is valuable context but not syntax beyond what the schema provides. Baseline 3 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 clearly states what the tool does: decomposes a portfolio's exposure to foreign currency and quantifies what exchange-rate moves contributed to growth, volatility, and worst fall compared with a hedged version. This is a specific verb+resource. Sibling differentiation is partially implied by the currency focus, but no sibling is explicitly named.

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?

Explicit when-to-use (only when some holdings are priced in another currency) and when-not (entirely in one currency, nothing to show), plus a prerequisite (base set to holder's currency). No alternative sibling is mentioned, but the condition is fully stated and leaves nothing to inference.

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