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

Annotations already cover readOnly/idempotent/non-destructive/openWorld, so the bar is lower, and the description adds genuinely new behavioral facts: this is a paid call at $0.001 USDC per successful call via x402 on Solana, plus an equivalent HTTPS endpoint. It omits error behavior for out-of-range n and any latency/rate context.

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?

Purpose and boundary examples come first, then the domain constraint, then pricing/access details. Four short sentences, each carrying distinct information with 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 one param, no output schema, and full annotation coverage, the description supplies enough to call it correctly: semantics of n, its range, sample outputs that reveal the return value is a count, and cost/transport. Only the response shape and out-of-range behavior remain unspecified.

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 single parameter n is unexplained in the schema (0% description coverage), but the schema does already encode minimum 1 and maximum 10000. The description restates that range and clarifies that n is an inclusive upper bound via the first sentence and examples — modest added meaning, not full compensation.

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 and resource: counting frugal numbers up to a bound n, with concrete example values (124→0, 125→1, 200→2). It does not, however, name or distinguish itself from the sibling `frugal` (presumably the per-number predicate), so an agent must infer count-vs-test from the name alone.

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: the worked examples make clear this is a prefix-count up to n, which implicitly steers away from `frugal` for single-number checks. There is no explicit when-to-use / when-not-to-use statement or named alternative.

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