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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavioral context: 'Uses real-time exchange rates for accurate conversions', which tells the agent that results are time-sensitive and may vary between calls. This goes beyond the 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 two short sentences with a clear action first: 'Convert a cryptocurrency amount to any fiat currency'. It adds one extra sentence about real-time rates. No filler or redundant content. The purpose and behavior are front-loaded.

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 (3 params, no nested objects), the schema fully describes each parameter, and an output schema exists. The description adds the key context that results use real-time exchange rates. There is no missing critical detail for an agent to call this tool correctly.

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 covers all three parameters with descriptions, so schema coverage is 100%. The description adds only marginal value by naming example currencies ('USD, EUR, JPY') which is already implied by the schema's description of the currency field. It does not clarify parameter formats or relationships beyond the schema, so it meets the baseline 3.

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 states a specific verb ('Convert') and resource ('a cryptocurrency amount to any fiat currency'), with concrete example currencies. It clearly distinguishes this tool from the price/get and market/rates siblings by focusing on conversion rather than just retrieving a price or rate.

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 clearly identifies the tool's use case: converting a crypto amount to fiat. It gives examples of target currencies but does not explicitly state when not to use it or name alternative tools. This is clear context but lacks exclusions or explicit alternative guidance.

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