engine_request_metrics

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

Annotations already declare readOnlyHint=true, so the safety profile is covered, and the '[READ]' prefix is redundant with that. The description does add one piece of real behavioral context – '(where the engine exposes them)' signals that some metrics may be unavailable depending on the backend – but says nothing about return format or time windowing.

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 tight elements – a bracketed tag plus metric list, and a single Args line. Front-loaded and free of filler, though the '[READ]' tag duplicates the readOnlyHint annotation.

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 single-optional-param read tool with annotations covering safety, the description tells the agent what it returns (the metric names) and how to scope it (target). It lacks only time-range/pagination context, which is minor here.

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%, so the description must carry the burden, and it does: 'target: Inference target name from config; omit for the default' explains both the value source and the default behavior. That meaningfully exceeds the empty schema, though it doesn't give format examples.

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 resource set – TTFT / TPOT / e2e latency plus generation-token totals – which is far more concrete than the generic name. It does not, however, distinguish itself from the sibling 'request_metrics' or 'diagnose_engine_latency', leaving the agent to guess which latency-metric tool to pick.

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 when-to-use guidance is given, and no alternatives are named despite 'request_metrics', 'diagnose_engine_latency', and 'diagnose_latency_spike' being obvious competitors. The only routing information is the param note 'omit for the default', which is about invocation, not tool selection.

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