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

No annotations are provided, so the description carries the burden. It discloses the output structure (last 20 health probes with status code, latency, alive, and uptime), which is useful. However, it omits behavior on missing/invalid ids, error responses, or whether the operation has side effects. For a read-only retrieval, this is a moderate gap but not severe.

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, well-structured sentence that front-loads the core purpose and include specific details (health probes, uptime) without fluff. Every word adds value, and it is neither overly long nor truncated.

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 simple one-parameter retrieval with an output schema, the description covers the essential return content (last 20 probes, uptime) and the prerequisite (id from x402_search). It does not mention error handling or edge cases, but given the output schema exists and the tool is straightforward, it is reasonably complete.

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 0%, so the description must compensate. It tells the agent the id comes from x402_search, which hints at the id's provenance and format. However, it does not elaborate on id syntax, examples, or constraints beyond the schema's type string. It partially compensates but leaves some ambiguity.

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 action (retrieve a single endpoint by id) and identifies the resource (x402 service index) and the return payload (last 20 health probes and uptime). It also references x402_search, which distinguishes it from siblings like x402_probe or x402_index_stats, making the intent unambiguous.

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 explicitly states the id comes from x402_search, implying you should search first before calling this tool. This gives clear context on when to use it, though it does not explicitly mention alternatives or when not to use it. The prerequisite is stated, which is helpful but not exhaustive.

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