mmex_currencies_by_symbol

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

No annotations provided, so the description carries the burden. It mentions optional db_path and db_key, implying authentication needs, but does not disclose side effects, read-only nature, error handling (e.g., if symbol not found), or return format beyond what output schema provides.

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 short and front-loaded with the main purpose. The Args section is structured but slightly redundant with schema. No wasted words, though could be more concise by omitting redundant 'Args' labeling.

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?

Given the output schema exists and the tool is a simple getter, the description covers parameters and purpose. Lacks details on not-found behavior or pagination, but these are unlikely needed for a single currency lookup.

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 0%, so the description adds value by explaining symbol as 'currency symbol (e.g., USD, EUR)' and clarifying db_path/db_key defaults and env var fallbacks. Could be more precise about symbol format restrictions.

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 explicitly states 'Get a currency by its symbol', uses specific examples (USD, EUR), and distinguishes from siblings like mmex_currencies_list (list all) and mmex_currencies_get (likely by ID).

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 explicit guidance on when to use this tool vs alternatives like mmex_currencies_list or mmex_currencies_get. Usage is implied by the function name and symbol input, but no when-not-to-use or alternatives are mentioned.

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