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

No annotations exist, so the description carries the full burden and does so well: it discloses that the call is paid ($0.004), the accepted payment rails (USDC on Arc/Base/Solana, XNT on X1), that no key or signup is required, and — most importantly — that over MCP the tool returns the price and URL rather than the data. That last point prevents an agent from wasting a call expecting a result set.

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 sentences, front-loaded with what the tool returns and immediately followed by the disambiguation rule; the payment detail is bulky in its parenthetical currency list but is necessary for a paid endpoint. No filler or marketing language.

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 one-parameter, no-output-schema tool, everything an agent needs is present: scope, ordering, cap, sibling alternative, cost, payment options, and the fact that MCP calls return price/URL instead of data. Nothing material is left to inference.

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 compensate. It confirms the ordering ('newest first') and the ceiling ('up to 50'), which are behavioral facts the bare integer schema does not convey. It does not mention the default of 20, but the ordering and max details make the single parameter interpretable.

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 specific resource and scope: 'Whale-sized swaps across ALL X1 tokens, newest first (up to 50)'. The ALL-caps 'ALL' plus the explicit contrast with recent_trades lets an agent distinguish this from the per-token sibling without opening either schema.

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?

Names the alternative explicitly ('For every trade of one token use recent_trades') along with the condition that selects it. The 'ALL X1 tokens' vs 'one token' split is a clean routing rule, and the 50-item cap sets expectations for volume.

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