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

With no annotations provided, the description carries the full burden and does add real context: rates are 'current' (not historical), sourced from ECB, and each call costs 1 credit. However, it says nothing about rate freshness/refresh cadence, precision or rounding of the returned value, or error behavior for unsupported currency codes.

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?

Two short sentences with the core operation front-loaded and the cost disclosure appended; nothing is wasted or 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 tool with no annotations, no output schema, and 0% parameter documentation, the description leaves too much unstated: the expected format of the result, rounding behavior, and currency-code format. The credit-cost disclosure is a positive, but the definition is not self-sufficient.

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 0% for all three required parameters. The phrase 'convert an amount between currencies' loosely maps to amount/from/to, but the description never clarifies that from/to are 3-letter ISO currency codes, nor does it explain the amount bounds or direction of conversion. It fails to compensate for the coverage gap.

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 ('Convert') and resource ('an amount between currencies') with the data source (ECB reference rates) named, which cleanly separates it from siblings like convert_data, subtitle_convert, and convert_media. An agent can identify the tool's function 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?

The description explains what the tool does but offers no when-to-use guidance, no prerequisites, and no alternatives or exclusions (e.g., historical vs. current rates, unsupported currencies). Usage is only implied by the tool's obvious domain.

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