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

With no annotations, the description carries the full burden, and it does disclose the key trait: no API call and no credit consumption. It does not describe the response shape or format of any reference section, and there is no output schema to compensate.

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 cost/behavior caveat is front-loaded in one clause, followed by a tight bulleted action map. Every line earns its place with no filler.

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 two-parameter reference lookup with a fully documented enum, the description gives an agent everything needed to choose an action. The only omission is any hint about the returned content format, which is minor for a documentation tool.

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% and the enum is described only as 'Reference topic to retrieve', so the description genuinely adds value by spelling out what each action returns (error table columns, retry strategy, penalty multiplier, etc.). The optional 'context' parameter is left unexplained, but it is trivial echo-back behavior.

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 opening line states exactly what the tool is — CryptoAPIs reference documentation — and the action list names each retrievable topic, letting an agent distinguish it from data siblings such as block_data__evm_block_data or block_data__utxo_block_data.

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 phrase 'no API call, no credits consumed' tells the agent this is the zero-cost lookup path, and the enumerated actions signal which topic to request. It stops short of explicitly saying 'consult this before calling other endpoints' or naming alternatives, but the context is unambiguous.

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