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

Adds a great deal beyond the readOnly/openWorld/idempotent annotations: USD 0.05 price with no free tier, typical sub-1s latency, the zero-sample and 404-not-charged edge cases, and an explicit prompt-injection warning about returned page text and on-chain strings. These are exactly the non-schema facts an agent needs before calling.

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 usage trigger and the return payload, then appends pricing, timing and a safety note. Dense but every sentence carries information; the title duplication at the start of the description is minor waste.

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?

Covers the selection trigger, the returned metrics, cost, latency expectation, degenerate-input behavior and a security caveat. With an output schema present, return-value detail is not required, yet the description still summarizes it usefully — nothing material 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% and the single `targets` parameter is fully documented (1-25 entries, endpoint URL or host name). The description restates the 'up to 25 endpoints or hosts' limit but adds no new syntax or format detail, so the baseline 3 applies.

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 and resource ('compare the 30-day uptime and valid-402 share of up to 25 x402 endpoints or MCP servers at once') and enumerates the returned metrics. The bulk scope clearly separates it from the single-target sibling get_endpoint_uptime.

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?

Opens with an explicit trigger condition ('Use when an agent must compare... at once'), which is exactly the bulk-vs-single decision an agent faces. It does not name the single-endpoint alternative outright, and no explicit when-not-to-use case beyond 'one vantage point' is given, so it falls short of a 5.

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