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

Annotations already mark this as readOnlyHint=true, non-destructive, closed-world, so the safety profile is covered. The description adds value beyond that: worst-case is a realised historical downside, not a forecast or recommendation; cross-currency pairs are shocked base-neutrally; simultaneous entries represent a correlated move; and partial coverage is surfaced in worst_case.coverage.

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?

Front-loaded with the core purpose in the first sentence, then mode mechanics, caveats, and the edge case. It is dense but every sentence carries distinct information, and the caveat ('not a forecast or a recommendation') is placed where it matters rather than buried.

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 complex multi-mode simulation tool, the description covers mode selection, semantics of the worst-case path, and the cross-currency edge case, and an output schema exists so return values need not be enumerated. Nothing an agent needs in order to invoke it correctly is missing.

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 100%, so the baseline is 3 and the schema already documents shock_bps sign convention and worst_case semantics. The description still adds meaning the schema omits, notably the base-neutral treatment of cross-currency pairs and the correlated-move interpretation of multiple scenario entries.

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?

States a specific verb+resource: 'Models the P&L impact of exchange rate moves on the user's current net exposure (invoices + cash) and existing hedges.' It also names the two operating modes and the exact scope of each, so an agent can distinguish this simulation tool from the surrounding get_* read tools without opening the schema.

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?

Explicitly lays out two modes with the condition that selects each: supply `scenarios` for a linear what-if, or set `worst_case: true` (scenarios then optional) for the historical adverse revaluation. It anchors worst_case to the Monitor dashboard KPI and provides a concrete worked example ('GBP/EUR moves 3% before Q3 close'), leaving little to inference.

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