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

Annotations already cover read-only, idempotent, open-world, and non-destructive traits. The description adds valuable context beyond that: the output switches to a decimal string past 15 digits, the exact n range, and that each successful call costs $0.001 USDC via x402 on Solana. It doesn't contradict annotations and provides real behavioral detail.

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 compact and front-loaded: it starts with the purpose and recurrence, then gives index bounds, output format, and payment details. Every sentence adds information an agent needs to call the tool correctly or understand its cost.

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 pure computation with no output schema, the definition is complete: it covers the recurrence, indexing, valid range, string-vs-number output behavior, and payment model. Nothing needed for correct invocation is missing.

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%, so the description carries the burden. It explains that n is the index into the hexanacci sequence, gives the 0–512 range, and supplies concrete examples (H(0)=0, H(5)=1, H(10)=16) that clarify the indexing convention. This compensates well for the bare schema.

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 clearly states it computes the nth hexanacci number and defines the recurrence with base cases, so the operation is unambiguous. However, it does not differentiate itself from sibling tools like hexanacci_index, hexanacci_step, hexanacci_mod, or hexanacci_sum, which an agent would need to distinguish among.

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?

No guidance is given on when to use this tool versus related siblings (e.g., hexanacci_sum for sums or hexanacci_step for the recurrence). The n-range constraint is a parameter bound, not usage guidance. The agent must infer selection from the name alone.

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