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

With no annotations, the description carries the burden of explaining behavior, and it does enumerate the metrics returned. However, it does not state whether this is strictly read-only, what the response shape looks like, or any limitations such as window boundaries or missing data behavior. It is not misleading, but it leaves the output format to inference.

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 two sentences with no filler. The metric list is front-loaded and the usage guidance is a separate, actionable sentence that earns its place.

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 tool with two parameters and a clear metric list, the description is mostly complete. The main gap is the lack of any return structure detail, which would be more important given there is no output schema, but the tool is simple enough that an agent can call it correctly from this description.

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%, with both site_id and window_minutes already described clearly. The tool description adds no additional meaning about these parameters, so the baseline score of 3 is appropriate.

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 the resource (one site, over a time window) and the specific content (requests, errors, latency percentiles, database share, N+1 count), so an agent knows exactly what this tool returns. It lacks an explicit verb like 'retrieves' and does not name a sibling to distinguish from, though 'before digging into anything else' positions it as the entry-point overview.

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?

'Use this before digging into anything else' is explicit guidance on when to invoke this tool: it is the first step before deeper investigation. It does not name specific alternatives or give when-not-to-use conditions, but the placement guidance is clear given the sibling tool set.

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