analyze_performance_metrics

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

With no annotations, the description must disclose behavioral traits such as read-only nature, side effects, or authentication needs. The description only mentions analysis and bottleneck identification, omitting details like whether screenshots are stored or if the tool modifies state.

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 a single sentence with an emoji, directly stating the purpose. It is highly concise with no redundant information, earning its place efficiently.

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?

Despite having 4 parameters and no output schema, the description provides minimal context. It does not mention the analysis duration, resource inclusion, or screenshot capture, leaving the agent uncertain about the tool's full capability and results.

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 100%, and each parameter has a clear description in the schema. The tool description adds no extra semantics beyond what the schema already provides, resulting in a baseline score of 3.

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 'Detailed performance analysis / Bottleneck identification' clearly states the tool's function with a specific verb ('analysis') and resource ('performance metrics'). It goes beyond a tautology by adding 'bottleneck identification', but does not differentiate from siblings like 'lighthouse_audit' or 'measure_web_vitals'.

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 (e.g., 'lighthouse_audit'). There are no prerequisites, exclusions, or contextual hints about appropriate scenarios.

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