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

With no annotations, the description carries the full burden, but it only states 'Live currency exchange rates.' It does not disclose behavioral traits such as data freshness, rate limits, authentication needs, or what happens if parameters are omitted. The agent gets minimal insight into the tool's behavior.

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 extremely concise at four words, which is structurally clean but overly terse. It could be expanded slightly to include key details without losing conciseness. As is, it is too brief to be fully useful.

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?

Given the tool has two parameters, no required fields, no output schema, and no annotations, the description is severely incomplete. It lacks information on return format, parameter usage, and any constraints. An agent would have insufficient context to use the 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 has two string parameters (base, target) with no descriptions and 0% schema description coverage. The description does not explain what these parameters represent (e.g., currency codes) or how to use them. It adds no meaning beyond the schema, leaving the agent to guess.

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 'Live currency exchange rates,' which conveys the general purpose but lacks specificity. It does not use a verb like 'get' or 'fetch,' and fails to clarify that it likely returns a specific rate based on base and target parameters. It vaguely distinguishes from siblings like 'crypto_price_simple' but does not explicitly differentiate.

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?

No guidance is provided on when to use this tool versus alternatives. There is no mention of use cases, prerequisites, or exclusions. The description is too terse to help an agent decide when to invoke this tool over similar ones.

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