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

Annotations already mark this read-only, and the description adds meaningful behavioral detail: include_series is off by default to keep the response small, series is 90 daily points, and the per-endpoint price field is in atomic token units, not dollars. This last warning is exactly the kind of non-obvious runtime behavior an agent needs.

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?

Every sentence earns its place: usage timing, returned fields, optional series behavior, and a critical units caveat. The most important guidance is front-loaded in the first sentence.

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 no output schema, the description carries the burden of describing the response, and it does so thoroughly: status, uptime windows, response time, networks, settlement asset, endpoints, assessment block, optional series, and units. For a simple slug lookup with two parameters, nothing essential 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 the schema already documents both slug and include_series. The description reinforces include_series behavior but does not add meaning beyond the schema, so it stays at the baseline.

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 clearly identifies this as the tool for retrieving the full service record behind a directory row once a slug is already held. The phrase 'the full record behind a directory row' plus the enumeration of live status, uptime, endpoints, and assessment block distinguishes it from lighter-weight search or assessment siblings.

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 gives an explicit when-to-use condition: 'Call this once you hold a slug and are deciding whether to commit to that service.' It does not explicitly name sibling tools or state when not to use them, but the 'slug already held' condition makes the intended context clear.

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