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

No annotations are provided, so the description carries the behavioral disclosure burden. It does convey that this is a read-style lookup returning fee rates, but it does not explicitly state side-effect-free behavior, data freshness, or how the result is returned. For a zero-parameter read tool this is acceptable 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?

The description is two sentences with no filler. The core output is front-loaded first, and the usage guidance with the alternative is compactly placed in the second sentence.

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 has no parameters and no output schema, so the description must explain the returned information; it does list the target intervals and the minimum fee, though it does not specify the exact response shape (e.g., JSON key names). That is a minor gap for such a simple no-arg lookup.

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?

There are zero parameters, so the baseline is 4; there is nothing the description needs to add about arguments. The description focuses on what the tool returns rather than parameters, which is appropriate here.

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 names a specific resource ('Recommended Bitcoin fees') and specifies exact confirmation targets (1/2/3/6/12/24-block) plus the mempool minimum fee. It clearly distinguishes this tool from btc_mempool_summary by stating the non-overlap, so an agent can tell them apart.

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 description explicitly says when to use the tool ('how much fee to pay, or what gets a fast confirmation') and explicitly says when not to use it ('overall congestion level'), naming the alternative btc_mempool_summary. This is ideal guidance.

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