get_rate

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

No annotations provided, so description must cover behavioral aspects. It discloses the dual-source fallback mechanism and that it provides mid-market rates. Absence of mention of rate latency or refresh frequency is a minor gap, but overall good transparency.

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 sentences, no redundancy. The most important info (what it does, source behavior) is front-loaded. Every sentence contributes.

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?

No output schema and description doesn't specify return format (e.g., numeric value, object). For a simple rate tool, the missing output description is a gap. However, the tool has decent annotations and simple parameters, so not critical but room for improvement.

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 coverage is 100% with parameter descriptions. Description adds context that it's the 'current mid-market rate' but doesn't add meaning beyond what schema provides for parameter semantics. Baseline is 3.

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 current mid-market exchange rate between two currencies' with specific verb and resource. Implicitly distinguishes from siblings like get_historical_rates and convert by specifying 'current' and 'mid-market'.

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?

Provides explicit guidance on data sources: uses Xe if credentials set, falls back to Frankfurter for free use. This helps the agent decide based on credential availability. No explicit when-not-to-use vs siblings, but the fallback behavior is clear.

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