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

Annotations only declare readOnlyHint and openWorldHint; the description adds the material facts an agent cannot infer: a 0.001 USDC per-call charge via x402 on Base, the mandatory two-call payment handshake, live external data sources, and a 'rule-based, not financial advice' caveat. Pricing and auth prerequisites are exactly the behavioral context annotations cannot carry.

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?

Front-loads cost and scope, then capabilities, then the call protocol — a sensible order with no filler sentences. It repeats the 0.001 USDC figure twice and includes the raw HTTP endpoint, which is marginally useful for an MCP caller but slightly redundant.

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?

No output schema exists, and the description compensates by enumerating the return payload (RSI14, SMA7, SMA20, 7-day change, score, reasons, exact source). Combined with the payment flow and input example, an agent has everything needed to invoke and interpret this 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%, so baseline is 3, but the description goes further by showing the literal input shape {"coin":"BTC"} and explaining that x_payment must be the signed payload derived from the terms returned on the first call. That causal relationship between the two parameters is meaning the schema alone does not convey.

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?

States a specific verb+resource (a long/short/neutral signal) with the exact asset universe (BTC, ETH, SOL, XRP, DOGE, ADA, LTC, AVAX, LINK, DOT and other USD pairs) and the data provenance (Kraken daily closes, Coinbase backup). This clearly distinguishes it from sibling price/market tools such as crypto_prices or crypto_market_metrics, which report data rather than a scored rule-based verdict.

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 two-step x402 flow is spelled out precisely: call once without x_payment to obtain payment terms, then call again with the signed payment to get the result. What is missing is explicit routing guidance against siblings (e.g. why use this over crypto_market_metrics for raw indicators), but the invocation context is unambiguous.

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