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

The description discloses the paid nature (cost per call) and specifies the HTTP method (GET). It also indicates it proxies an upstream request. While it doesn't delve into error handling or rate limits, given the absence of annotations, this is useful and adds context beyond the schema. No contradictions.

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 relatively long but well-structured, covering pricing, functionality, alternatives, input formats, and an example in a logical flow. It is informative without being redundant, though slightly verbose. The key details are front-loaded, making it easy to scan.

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?

The tool is simple and self-contained. The description explains what it returns, how to specify inputs, and when to use it, with an example. Since there is no output schema, the return fields are described adequately. All necessary information for a correct call is present, making it complete.

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 schema only defines generic 'body' and 'query' objects with additionalProperties, so the actual parameters (coins, currency) are not structurally defined. The description compensates by naming the parameters and giving examples, but it doesn't specify whether they are required or optional, nor their exact locations in the request (query vs body). This partial coverage warrants a mid-range score.

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's purpose: providing live crypto prices for one or many coins, returning last price, 24h change, volume, and market cap. It also distinguishes it from siblings by explicitly naming alternatives for ranked market-cap tables and candles, making it easy to select.

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?

It gives explicit guidance on when to use this tool: as the simplest crypto price read, and when to use alternatives. It also explains the input formats (ticker symbols for top ~50, CoinGecko IDs for all) and provides an example query, leaving no ambiguity about invocation.

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