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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is fully covered by structured data. The description adds only the derived 'verdict' notion and the returned aggregates; it says nothing about snapshot freshness or whether the values are node-local point-in-time readings. Adequate on top of annotations, but not rich.

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?

Three front-loaded segments: what it is, when/when-not, and what comes back. No filler prose; the dense field list is justified because no output schema exists.

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 and no parameters, the enumerated return fields (txs, bytes, usage_mb, max_mempool_mb, load_pct, min_fee_btc_kvb, total_fees_btc, verdict) are exactly the compensating information an agent needs, and annotations cover the safety profile.

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 the baseline is 4 and there is nothing for the description to clarify beyond confirming it is argument-free.

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 (Bitcoin mempool depth/capacity load) and further pins down what is measured via the 'busy/normal verdict'. It is clearly distinguishable from sibling btc_get_fee_rates, which it explicitly names as the tool for fee choice.

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?

Explicit 'When to use' (deciding whether now is a good moment to settle on-chain, or sizing the backlog) and an explicit 'Do not use' clause routing fee selection to btc_get_fee_rates. Nothing is left to inference.

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