get_performance_metrics

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

With no annotations, the description fully discloses behavior: no side effects (read-only snapshot), return format (JSON object with numeric values), and examples of returned metrics. It leaves no ambiguity about the tool's operation.

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 and well-structured. It leads with the core action, then covers side effects, prerequisites, returns, use cases, and alternatives in a logical flow without unnecessary words.

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?

Given no output schema and no annotations, the description is fully complete. It covers all necessary aspects: purpose, side effects, prerequisites, return format, typical use cases, and alternatives. No gaps remain.

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 tool has zero parameters (schema coverage 100%), so the baseline is 4. The description adds value by explaining the return value structure and giving examples of metric names, which helps the agent understand what the output contains.

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 action (captures runtime performance metrics) and specifies the resource (active Chrome tab). It lists specific metrics (JS heap size, DOM node count, layout timing) and distinguishes itself from siblings by naming alternatives like 'profile_page_performance'.

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 provides explicit usage scenarios: monitor memory usage, detect memory leaks, profile performance. It states prerequisites (requires an active Chrome tab) and offers clear alternatives for different needs (detailed tracing, browser DevTools).

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