Get Exchange Rate

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, establishing safety. The description adds that the tool returns a 'Current exchange rate with timestamp,' which is useful behavioral context beyond the schema. No contradictions with annotations.

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, structured with Args, Returns, and Examples sections. Every sentence adds value with no redundancy. The main purpose is front-loaded in the first line.

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 2-parameter tool with rich annotations and 100% schema coverage, the description is complete. It covers purpose, parameters, return format, and examples. There is no output schema, but the description explains the return value adequately. Slight deduction for lacking error handling or edge cases.

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 good descriptions for both parameters. The description adds a returns section and concrete examples (e.g., 'XAU/USD' for gold), which adds value beyond the schema by clarifying usage patterns. This justifies above baseline (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?

The description clearly states 'Get the current exchange rate for a currency pair' with a specific verb and resource. It uses examples like 'EUR/USD' and 'XAU/USD' to clarify the resource scope, effectively distinguishing from sibling tools like twelvedata_get_price which likely fetches stock prices.

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 provides examples and expected input formats, giving clear context for when to use the tool. However, it does not explicitly state when not to use it or mention alternatives like twelvedata_convert_currency for conversion with amounts, so it narrowly misses a 5.

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