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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds genuinely non-structured behavior: the $0.001 USDC per successful call charge via x402 on Solana, and the HTTPS endpoint mirror. That is valuable context an agent cannot get from annotations or schema.

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 definition and formula are front-loaded, followed by the example terms, the valid range, price, and endpoint. Every sentence carries information – no filler – though the pricing/URL tail makes it slightly dense for a single-value math 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?

For a read-only single-integer math function with no output schema, the description supplies the domain definition, the output semantics (a bit that is 1 or 0), the valid range, the cost, and the alternate endpoint. An agent has enough to call it correctly; the only gap is sibling routing.

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?

Schema description coverage is 0%, so the description must carry parameter meaning. It does explain n mathematically through the m·2^k decomposition and fixes the starting point with the first three bits, but it does not explicitly restate that n is an integer index ≥ 1 (the schema bounds already imply that). Adequate but incomplete 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?

The description gives a precise verb+resource: it computes the regular paperfolding bit at index n, with the exact decomposition rule (n = m·2^k, bit = 1 when m ≡ 1 mod 4, 0 when m ≡ 3 mod 4) and sample values 1,1,0. That is unambiguous and far beyond a tautology. It does not differentiate itself from similarly named siblings such as paper_next or the unrelated paper_size/paper_fit, so it stops short of a 5.

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 never says when to use this tool versus alternatives (e.g., paper_next for stepping the sequence) or when not to use it. The only guidance is the domain restriction n ∈ [1, 1000000] and the pricing note. An agent must infer the use case entirely from the math.

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