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

The annotations provide only readOnlyHint: true, so the description carries most of the behavioral disclosure burden. It adds useful context beyond that: 'Answers in formatted text' describes the return format, and 'Costs 3 units of the monthly quota' warns about an important side effect (quota consumption) that annotations don't cover. It also implies ranked output by saying 'RANKED LIST'. It doesn't describe pagination or error behavior, but for a simple read-only list tool this is substantial added 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?

The description is dense and front-loaded: the first sentence states purpose and parameters, the second gives usage conditions and alternatives, and the last two sentences cover output format and quota cost. Every sentence carries necessary information without repetition or fluff, making it efficient for an agent to parse quickly.

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 tool with only 2 parameters and no output schema, the description covers the essential context: what it returns, when to use it vs alternatives, the quota cost, and the response format. The ranking order ('highest Martingale Score first') is documented in the schema's limit parameter, and read-only behavior is in annotations. It could be slightly more explicit about the default behavior (limit=10) but that is available in the schema, so the description is adequately complete for its complexity.

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?

The input schema has 100% description coverage, so both parameters are fully documented with ranges, defaults, and meaning. The main description only paraphrases the parameters ('choose how many (1-20) and an optional minimum Startingale') and adds no additional semantic detail beyond what the schema already provides. Per the rubric, the baseline of 3 applies because the description adds minimal value over the schema.

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 opens with 'A RANKED LIST OF CRYPTOS, sized by you' which clearly identifies the verb (list) and resource (cryptos), and specifies the two adjustable parameters (count and minimum Startingale). It explicitly differentiates from siblings by stating that anything beyond these two conditions requires search_instruments, and that a fixed top 5 with no arguments is crypto_overview. This fully distinguishes it from the sibling tools.

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 gives explicit when-to-use guidance: 'Use this when those two are the ONLY conditions', and then explicitly names the alternative for additional criteria ('needs search_instruments') and for a simpler variant ('For a fixed top 5 with no arguments, use crypto_overview'). No inference is required on when to pick this tool over its siblings.

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