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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive hints, so the description does not need to repeat those. It adds meaningful behavioral context: the cost per call, the byte-identical claim to a GET endpoint, and the word 'One shot' implying no pagination or filtering. This goes beyond the annotations without contradicting them.

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 a single, dense sentence that front-loads the purpose ('One shot at the network's aggregate state') then lists the exact fields, then adds the cost and endpoint equivalence. Every element earns its place, with no filler or repetition. Ideal length for a no-parameter tool.

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 an output schema exists (though not fully shown), so the description does not need to detail return structure. It covers what the tool returns (by listing fields), the cost, and the endpoint equivalence. The only minor omission is that it does not describe any caveats such as rate limits or possible empty responses, but for a simple stats tool this is negligible. The description is sufficiently complete for safe invocation.

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 schema requires no explanation. The description does not attempt to document any parameters because none exist. A baseline of 4 is appropriate given that parameter semantics are moot; the description correctly omits any detail that would be irrelevant.

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 is explicit: 'One shot at the network's aggregate state' and then enumerates the exact data points (price, hash rate, difficulty, etc.). This clearly distinguishes it from sibling tools like market_btc_spot_prices or market_btc_mining_hashrate, which focus on single metrics. The tool's scope is unambiguous.

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?

It implicitly guides usage by framing the tool as a single-shot aggregate snapshot, and it adds a critical usage constraint: a per-call cost of $0.001 USDC, which agents should weigh when deciding to call. It does not explicitly name alternatives or exclusion criteria, but the list of fields makes it obvious that this is for broad overviews rather than targeted queries. The absence of explicit when-not-to-use is a minor gap.

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