get_performance_metrics

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

With no annotations, the description carries the full behavioral burden and discloses almost nothing: it doesn't state whether the call is read-only, whether a live session/page is required, what happens for a stale or invalid session, or what the returned metrics look like. Only the bare 'from the page' hint about scope is added.

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?

One short, front-loaded sentence with no filler. It is efficient, though brevity here reflects under-specification rather than disciplined editing.

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 tool with no annotations, no output schema, and an undocumented required parameter, the description should say more about input expectations and return content. As written, an agent cannot determine what metrics are returned or how to supply a valid session.

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 0% and the single required parameter sessionId is a UUID with no textual explanation in either the schema or the description. The description adds no meaning about what sessionId is, where to obtain it, or what happens if it's missing.

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 names a verb ('Get') and a resource ('performance metrics') scoped to 'the page', which is enough to distinguish it from unrelated siblings like click or navigate. However, 'performance metrics' is broad and unspecified, and it doesn't differentiate from adjacent read tools such as get_page_info, get_logs, or get_console_messages.

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?

There is no guidance on when to use this tool versus alternatives like get_page_info or get_console_messages, no prerequisites (e.g. a page must be loaded), and no exclusions. The agent must infer context entirely.

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