network_timings

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

With no annotations, the description carries the transparency burden. It adds a useful behavioral note that zero transferSize on a non-cached entry usually indicates a failed request, but it does not disclose other details such as read-only status, output format, or how max_entries affects results.

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 extremely concise, with the primary purpose in the first sentence and a valuable troubleshooting tip in the second. Every sentence adds value and there is no 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 one optional parameter and no output schema, so the description needs to explain what the tool returns and how parameters work. It provides the data source and a behavioral hint but leaves the max_entries parameter unexplained and does not describe the result structure in enough detail for an agent to know what to expect.

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?

The description does not mention the max_entries parameter at all. Since schema description coverage is 0%, the description must compensate but fails to explain the parameter's meaning or default behavior.

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 tool as returning resource timings from the Performance API, listing the fields (URL, type, duration, transfer size). This distinguishes it from sibling tools like console_logs or page_source, which serve different purposes.

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?

No guidance is provided on when to use this tool versus alternatives. The description neither states specific use cases nor mentions sibling tools, leaving the agent to infer from the name.

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