get_exchange_rate

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

No annotations provided, so description carries full burden. It states the tool returns a single rate number and requires an API key, which are key behaviors. It does not cover potential rate limits or error handling, but for a simple read operation, it is sufficiently 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?

Two concise sentences: first explains purpose, second states requirement. No unnecessary words, front-loaded with key information.

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 tool with 2 required parameters and no output schema, the description adequately states it returns a rate number and mentions API key requirement. No gaps given the tool's complexity.

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 detailed descriptions for both parameters (ISO 4217 currency codes). The description adds 'mid-market' context but does not enhance parameter semantics beyond what the schema already covers. With 100% schema description coverage, 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?

Description clearly states 'Get the current mid-market exchange rate between two currencies. Returns a single rate number.' The verb 'Get' and resource 'exchange rate' are specific. It distinguishes from siblings like get_historical_rates (historical data) and list_currencies (list of codes).

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 includes a prerequisite: 'Requires API key (ALLRATES_API_KEY).' However, it does not explicitly state when to use this tool versus siblings like get_historical_rates or get_rates_authenticated, leaving some ambiguity.

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