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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is clear. The description adds valuable behavioral context on top: it reads UserOperationEvents, has pricing ($0.05/call, free tier), requires no wallet/API key, and expects a prepaid header for unlimited calls. This meaningfully supplements the annotations without contradicting them.

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 a single dense paragraph, but it is front-loaded with the core purpose and then covers usage, parameters, pricing, and authentication efficiently. Minor extras like 'Not financial advice' add some noise, but overall each major clause contributes useful information.

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, the description does not need to enumerate return fields. It covers the key contextual requirements for a successful call: required input, optional parameters with defaults, intended use cases, pricing, and access method. Nothing essential is missing for an agent to select and invoke this tool correctly.

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?

Input schema coverage is 100%, with both 'paymaster' and 'days' described. The description adds important semantics beyond the schema: paymaster is required, days is optional with a default of 30 and max of 90. This helps an agent construct a valid call even though the schema already documents parameter types.

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 opens with a clear, specific question: 'Should you trust this Base gas paymaster?' and then states the concrete action: 'audits whether it's a healthy, active gas sponsor' by reading UserOperationEvents across both EntryPoints. This clearly distinguishes it from general address trust tools by focusing on paymaster-specific metrics and integration use cases.

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?

The description explicitly names the intended use: 'The read to run before integrating a paymaster (Coinbase / Pimlico / Alchemy / custom), or judging who funds a counterparty's gas.' This gives clear contextual guidance, though it does not explicitly mention when not to use it or name a specific alternative tool.

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