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

With no annotations, the description carries the full burden. It usefully discloses that access requires payment (0.01 USDC on Base via x402, 12 sats Cashu or Lightning), which is real behavioral context an agent must know. However, it says nothing about data freshness, caching, rate limits, or failure modes on unpaid calls.

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?

Two tight sentences, front-loaded with the payload contents before the payment detail. Every clause carries information, though the payment sentence is dense enough to be slightly hard to parse.

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?

With no output schema, the enumeration of returned fields partially compensates, and the payment disclosure is valuable. But the undocumented 'currency' parameter and total absence of usage guidance leave gaps for a paid, multi-source data 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 0%: the single optional 'currency' parameter has no description in the schema, and the description never mentions it. 'Fiat prices' only hints that currency matters, giving no format or default behavior, so the description fails to compensate for the coverage gap.

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?

Names a specific resource (Bitcoin snapshot) and enumerates exactly what it returns: fiat prices, recommended fees, mempool size, block height, difficulty adjustment. An agent can tell what data it yields, though it never explicitly distinguishes itself from siblings like lightning or crypto.

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 when-to-use guidance and no alternatives named. The payment sentence describes cost mechanics, not selection criteria, so the agent gets no help deciding between this tool and fx_rates, crypto, or lightning.

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