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

With no annotations, the description carries the full burden and does disclose key traits: the pricing model ($0.005 USDC on Base via x402), the no-auth model, the two-call payment handshake, and the inclusion/exclusion scope. It omits return format and any rate-limit behavior, which prevents a 5.

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 pricing/payment sentence is front-loaded ahead of the actual semantics of what the tool returns, so the purpose is buried near the end. Nothing is egregiously wasteful, but the ordering hurts fast comprehension.

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 low-complexity read/list tool with two optional parameters and no output schema, the description covers purpose, scope exclusions, auth model, and payment mechanics adequately. It could still say what fields are returned or the default lookback window, but nothing essential for calling it correctly is missing.

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 both `days` and `payment` are already documented in the schema, making 3 the baseline. The description restates the `payment` handshake but adds no syntax or format detail beyond what the schema provides, and never mentions the `days` parameter's 1-30 range.

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 states a specific behavior: it lists services that used to answer and have stopped, explicitly excluding never-alive services. This distinguishes it from siblings like new_services and uptime_history. The purpose is clear but the terse 'Gone dark.' opener defers the real meaning to the final sentence.

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?

It explains the payment invocation flow (call without `payment` to get requirements, call again with `payment`), which is useful procedural guidance. However, it gives no guidance on when to choose this tool over siblings such as uptime_history or get_liveness_history.

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