convert_currency

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

With no annotations, the description carries the full burden. It does disclose the real-time nature ('latest rate') and the Pro plan requirement. However, it does not mention whether the operation is safe/read-only, any potential side effects, error behavior, or what the result looks like. Some behavior is implied by 'convert', so this is adequate but not thorough.

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 concise sentence with no redundancy. It front-loads the core purpose and appends the requirement as a separate clause near the end, earning its place without extraneous detail.

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 3-parameter conversion tool with 100% schema coverage proportional to its complexity, the description covers the essential behavioral aspects: what it does, when it does it (latest rate), and an access constraint (Pro plan). The lack of an output schema means return format is not an obligation, and no major contextual gaps are evident.

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% parameter coverage with clear descriptions and examples for from, to, and amount. The description adds no additional parameter meaning beyond the schema, so the baseline score 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 uses a specific verb ('Convert'), a clear resource ('amount from one currency to another'), and a timing qualifier ('at the latest rate'). This distinguishes it from rate-only siblings like get_pair_rate and get_latest_rates by making clear that it performs a conversion rather than just returning a 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 only usage-related information is the prerequisite 'Requires Pro plan or higher.' There is no guidance on when to use this tool instead of siblings such as get_pair_rate, get_historical_rates, or get_latest_rates, so an agent must infer which tool is appropriate.

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