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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, openWorldHint, non-destructive), but the description adds genuinely non-structured context: $0.02 per call over x402, a prepaid x-credit-token header for unlimited calls, 1 free call/day per tool, and no API key required. These auth/payment/rate-limit details are exactly what annotations cannot convey.

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 output list, then adds scope and payment terms; every element is relevant. The rug aphorism is a minor flourish, but it efficiently conveys the tool's intent rather than restating the name.

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 need no explanation, and the description covers purpose, inputs, cost model, and audience. It leaves minor gaps: what happens if 'size' is omitted, and whether the check is strictly Base-only — both of which an agent calling this correctly would want to know.

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 description coverage is 100%, so the schema already documents both 'address' (token contract address) and 'size' (trade size in USD), making the baseline 3. The description adds only that address is required and frames size as an input to supply, which is slightly at odds with size being optional in the schema; no format, default, or omission behavior is clarified.

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?

Names a specific verb+resource outcome: given a Base token and USD size, it returns buy and sell price impact, unwindability without collapsing the pool, and the largest safe exit. The rug framing ('you can't sell') separates it from buy-side risk siblings like rug_score, dump_risk, and contract_danger.

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 for use — 'Built for trading agents sizing positions' — and the framing sentence tells the agent this is the sell-side/unwind check. However, it never names alternatives (sellability, price_impact, position_health) or states when-not to use it, so an agent must infer the boundary from scope alone.

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