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

Annotations already cover read-only, idempotent, non-destructive and open-world behavior, so the description's added value is the pricing model ($0.001 USDC per successful call via x402 on Solana), the domain constraint 1–20000, and the HTTPS mirror endpoint — real operational context an agent needs before committing to a paid call.

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?

Four short sentences: definition first, examples second, domain third, cost/alternate endpoint last. No filler, and the most decision-relevant information (what it returns) is front-loaded.

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?

No output schema exists, but the examples make the return value (a single integer) obvious, and cost plus domain are disclosed. Only gap is that the return type is never stated explicitly — an agent infers integer from the examples rather than being told.

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 must carry parameter meaning. It does: n is the lower bound (smallest result >= n), the valid range 1–20000 is restated, and four worked examples pin down the exact semantics better than any prose definition of 'Duffinian'.

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 precise verb-less but unambiguous operation: return the smallest Duffinian number >= n. The 'at least n' phrasing plus concrete input/output examples (1→4, 5→8, 10→16, 22→25) distinguish it clearly from sibling duffinian (membership) and duffinian_next-style relatives.

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 implied rather than stated: an agent infers it should call this when it needs the next Duffinian at or above a bound. No explicit comparison to siblings like duffinian, duffinian_sum or duffinian_count, and no stated restrictions beyond the numeric domain.

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