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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description adds genuinely new operational context: a per-call price of $0.001 USDC via x402 on Solana and an equivalent HTTPS endpoint. It does not state error behavior for out-of-range input, but the paid-call disclosure is exactly the kind of trait annotations cannot convey.

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 tight sentences: definition first, examples second, pricing and endpoint last. Each element earns its place; only the endpoint URL is arguably auxiliary, but it is genuinely useful for an agent that can't use MCP transport.

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 a single integer parameter, no output schema, and full annotation coverage, the description supplies everything needed: what is computed, the domain, illustrative outputs, and the payment/access model. It lacks only guidance on boundary or invalid input handling.

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 — and it does, specifying that n runs from 0 to 999999999999 and illustrating concretely how specific n values map to results. The worked examples clarify the input/output relationship better than a type declaration could.

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?

Names a precise quantity — the digit count of the base -2 (negabinary) representation of n — and the three worked examples (0→1, 4→3, 6→5) make the output unambiguous. It does not, however, distinguish itself from close siblings negabinary, negabinary_bits, negabinary_digit, or negabinary_decode.

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 examples and the stated domain (0 to 999999999999) imply when the tool applies, and effectively warn that inputs must be non-negative and bounded. There is no explicit instruction on when to prefer this over negabinary_bits or negabinary_digit, so selection still requires inference.

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