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

No annotations are present, so the description carries the full burden. It clearly discloses what the tool returns (PHP errors with file/line, 5xx without PHP errors) and hints at the output containing ids via the phpray_trace reference. It doesn't mention ordering or pagination, but these are minor for a list tool.

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?

Two sentences with no fluff. The primary purpose is front-loaded, and the second sentence adds a valuable cross-reference to phpray_trace. Every word 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 list tool with no output schema, the description provides sufficient context: what it returns, the nature of failures, and how to drill down. It doesn't detail the exact response structure, but that is likely inferred from the context and is not critical for calling the tool correctly.

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 no additional meaning about limit, site_id, or window_minutes beyond the schema, but it doesn't need to since the schema already documents them.

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 verb and resource: lists failed requests on a site, distinguishing PHP errors/warnings (with file/line) from 5xx responses without PHP errors. This clearly separates it from siblings like phpray_slow_pages (performance) or phpray_traces (all requests).

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 explicitly routes the user to phpray_trace for deeper investigation of an individual error, providing a clear alternative. It implies this tool is for the list-level view, though it doesn't explicitly exclude other siblings like phpray_alerts or phpray_compare.

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