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

Annotations already declare readOnlyHint and openWorldHint, so the bar is lower, yet the description adds genuinely useful operational context: the upstream source (mempool.space) and, critically, the payment model — $0.002 USDC per successful call via x402 on Base/Solana/Arc, with failed calls not charged. That cost/billing disclosure materially affects an agent's decision to call. It does not cover freshness/caching or latency.

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 sentences, front-loaded with the metric list, and the second sentence carries pricing that cannot be inferred elsewhere. Dense but every clause maps to a returned field or a cost the caller must know; 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?

With an output schema present, the description need not explain return shapes, and it still pre-summarizes the key metrics, names the data source, clarifies network-wide scope, and discloses pricing. Only the absence of explicit sibling routing keeps it from a 5.

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 tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. The description correctly implies a parameterless, snapshot-style call.

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 enumerates exactly what is returned: hashrate in EH/s with 3-day averages, current difficulty, epoch progress and expected change, plus miner revenue over the last 144 blocks. The 'network-wide figures from mempool.space, not per-miner' clause scopes it clearly. It stops short of naming the sibling it should be chosen over (e.g. crypto_bitcoin_mempool_stats), so it is clear but not sibling-differentiated.

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?

Usage is only implied: an agent can infer this is for Bitcoin network health/miner-economics questions, and the 'not per-miner' note rules out miner-level use. There is no explicit 'use this instead of X when Y' guidance despite several closely related siblings (crypto_bitcoin_mempool_stats, finance_mempool_bitcoin).

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