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

With no annotations, the description carries the full burden. It discloses the data source (Bank of Taiwan) and the rate types included (cash and spot buy/sell prices), which is useful behavioral context. However, it omits update frequency, whether rates are real-time, and any output format details, so it is only moderately transparent.

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 definition is a single sentence with zero waste and the core resource is front-loaded after a brief category tag. It is appropriately sized and easy to parse, though the bracketed prefix is mildly redundant.

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 lookup tool with a fully documented one-parameter schema and no output schema, the description is nearly complete: it names the source, covered currencies, and rate types. It would benefit from return-format details and usage distinctions, but nothing critical 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% and the single optional parameter 'cur' is fully documented in the schema (comma-separated currency codes with examples). The description adds no additional parameter meaning, so the baseline of 3 applies.

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 resource (Bank of Taiwan posted exchange rates) and scope (NTD to various currencies, cash and spot bid/ask). It clearly tells what the tool does, but it does not distinguish itself from sibling trip__convert_currency, so it falls short of full sibling differentiation.

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 bracketed tag '[Practical queries for overseas and domestic travel]' hints at a travel context but gives no explicit when-to-use or when-not-to-use guidance. It never mentions alternatives such as trip__convert_currency, leaving the agent to infer the appropriate scenario.

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