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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive hints. The description adds useful behavioral context: live rates, 150+ currencies, and daily updates, which informs the agent about data coverage and freshness. It does not contradict any annotations.

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 a single, compact sentence that front-loads the core action and includes key constraints (150+ currencies, daily updates). No wasted words; every element adds value.

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 simple currency conversion tool with a well-documented schema and strong annotations, the description is adequately complete. It does not specify the exact return format, but given no output schema and the straightforward nature of the operation, this is a minor gap. Overall, the tool is well-specified.

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 input schema provides 100% coverage for all three parameters with descriptions (from, to, amount). The description itself does not add additional parameter-level meaning beyond what the schema already conveys, so a baseline of 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 the action 'Convert an amount between two currencies' with scope (live rates, 150+ currencies). This distinguishes it from sibling tools, which focus on fuel prices, events, and weather, none of which handle currency conversion.

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 implies when to use the tool (when currency conversion is needed) and provides context about live rates and daily updates. It does not explicitly list exclusions or alternatives, but since no sibling tool offers similar functionality, the usage context is clear and unambiguous.

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