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

With no annotations, the description carries the full burden. It does disclose a default behavior (if no range given, compares day before yesterday vs last 24h), which is useful. However, it does not mention whether the tool is read-only, what the output format is, or any constraints like authentication or rate limits.

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 concise at two sentences, with the purpose front-loaded and a clear usage example. Every sentence earns its place without redundancy.

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?

The tool has 5 parameters, 1 required, no output schema, and no annotations. The description explains the purpose and a default but does not describe what the tool returns (e.g., a table, metrics), nor does it differentiate from siblings like phpray_overview or phpray_traces. Given the complexity and lack of annotations, more context is needed.

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 coverage is 100%, so the baseline is 3. The description adds minimal value beyond the schema—only clarifying that 'from_a' is the earlier start and giving a default. It doesn't explain the relationship between ranges A and B further or any parameter interactions.

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 states the tool compares two time ranges for one site side by side, and implies a comparison for evaluating changes. It's not a tautology and the purpose is understandable, but it doesn't specify what metrics are compared (e.g., performance, errors), which slightly limits clarity.

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?

The description gives a specific use case: checking whether a deployment, plugin update, or configuration change improved or worsened things. This provides clear when-to-use guidance, though it doesn't mention alternatives or when not to use the tool, leaving some ambiguity.

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