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

Goes well beyond annotations by disclosing the pricing model ($0.03 per call over x402 on Base), the prepaid x-credit-token header option, a free call/day allowance, no API key requirement, and the conservative constant-product assumption. Annotations only cover readOnly/idempotent safety; the description carries the operational context.

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?

Front-loads the core question and computation, but carries some promotional and boilerplate text ('Not financial advice', the $5k/$20k illustration) that adds length. Most sentences still earn their place by conveying method or payment mechanics.

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 an output schema present, return values needn't be described, yet the model is explained (constant-product, conservative, deepest Base pool). Payment mechanics and required inputs are covered, and annotations already carry the safety profile, leaving no critical gap for correct invocation.

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 100%, so the schema already documents address, size, and side (with its buy/sell default). The description restates 'Pass address= and size= (USD)' and notes defaults but adds no syntax or format detail beyond the schema, so it sits at the baseline.

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 verb+resource with scope: computes the exact x*y=k price impact of a given USD trade size on a token's deepest Base pool, and returns the largest size under 1% and 3% impact. Clearly distinguishable from siblings like token_price, swap_route, or price_alert, which it implicitly contrasts ('a quote shows today's price').

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?

Gives clear context: 'size before you buy' and explains the scenario where it is needed versus a spot quote. It names swap-route as the confirmation alternative, though it doesn't state exclusions such as when the constant-product approximation is invalid or non-Base chains.

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