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

Annotations already declare readOnly/idempotent/non-destructive, so the safety bar is low, yet the description adds genuinely non-obvious behaviour: a per-call price ($0.001 USDC via x402 on Solana), an equivalent HTTPS endpoint, and the sign convention (bit 1 maps to sign -1). It does not describe the response shape or error behaviour for out-of-range n, keeping it below 5.

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?

Definition first, then examples, range, price, and alternate endpoint — a sensible front-loaded order with no filler. The pricing/endpoint sentence is dense but each clause carries operational information an agent needs.

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 single-parameter deterministic math tool with no output schema, the description covers input domain, interpretation, output meaning, cost, and transport. The only real gap is error handling for n outside 0–1000000 and the exact response structure, which are minor for this complexity.

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 coverage is 0% (the single integer parameter is undocumented in the schema), so the description must carry the semantic load. It does: the valid interval 0–1000000 and the two worked values (n=3 → bit 1, sign -1; n=0 → 0) clarify both meaning and output mapping far beyond the raw type.

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 mathematical definition ('parity of the number of overlapping 11 blocks in its binary expansion') plus worked examples, so the agent knows exactly what is computed. It stops short of differentiating from neighbouring sequence tools (golay_rudin, thue_morse, paperfold), which is why it lands at 4 rather than 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 valid domain (n from 0 to 1000000) and the payment requirement are stated, which frames when the tool is callable. There is no explicit guidance on when to choose this over sibling sequence functions or what happens outside the range; usage is implied by the definition alone.

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