Get latest exchange rates

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

With no annotations, the description carries the full burden and does substantial work: it discloses that rates are returned as strings, that refresh frequency varies by plan (daily/hourly/10min/60s), and that the response can balloon to 1000+ entries. It stops short of describing error behavior or the response shape (e.g. a code→rate mapping).

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?

Three sentences, front-loaded with purpose and followed by constraints and the key caveat. The plan-tier refresh sentence is dense but earns its place; nothing is redundant enough to cut.

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 two-optional-parameter read tool with no annotations and no output schema, the description covers scope, return type, freshness, and response-size risk. The main gap is the shape of the returned payload, which matters here precisely because no output schema exists.

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%, so both parameters are already fully documented, including the default base of USD, the comma-separated symbol format, and the advice to prefer passing symbols. The description's 'Omit symbols to get all 1000+ currencies' restates the schema, so the baseline 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?

States a specific verb and resource (returns latest exchange rates) plus scope (fiat, crypto, metals; against a base currency). The word 'latest' implicitly separates it from get_historical_rates, get_time_series, and get_fluctuation, but no sibling is named, so an agent must infer the boundary rather than read it.

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?

Usage guidance is limited to parameter-level advice ('Omit symbols to get all 1000+ currencies'). There is no statement of when to pick this over convert_currency (single conversion) or get_historical_rates, and no mention of the plan prerequisite for changing base beyond what the schema already says.

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