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

The description discloses that rates are aggregated by median across multiple named sources and that 24h change is included. This adds value beyond empty annotations, but it does not cover aspects like refresh frequency, rate limits, or whether the data is real-time.

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 two sentences long, front-loads the core purpose, and includes essential details (aggregation method, data sources) with no unnecessary words.

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?

While the tool is simple (2 params, no output schema), the description omits information about the response format or structure, which would help an agent interpret results. It adequately covers purpose and data source aggregation but lacks completeness for a fully self-contained definition.

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%, but the description adds context: base asset can be crypto or fiat, quotes default to USD and accept comma-separated values. This provides practical guidance beyond the schema's parameter descriptions.

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 clearly states the tool gets the latest aggregated exchange rates for a base asset against quote currencies, with 24h percent change. It distinguishes from siblings like convert_currency (conversion) and get_rate_history (historical data) by focusing on current rates.

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 (convert_currency, get_rate_history). The description simply states what it does, leaving the agent to infer usage context without explicit when/when-not instructions.

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