Record code coverage

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

With no annotations, the description must disclose behavioral traits on its own. It mentions start/stop and optional CSS tracking, but fails to explain session lifecycle, what happens to existing coverage data, whether results are returned on stop, or the required session context. Significant behavioral gaps remain.

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 that is direct and front-loaded with the verb. It contains no filler and efficiently conveys the core action, earning a high score for conciseness and structure.

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 four parameters, no output schema, and no annotations, the description is too brief to be complete. It does not explain return values, session semantics, or how parameters like sessionId and targetSessionId are used, leaving the agent under-informed for correct invocation.

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 coverage is 0%, so the description must compensate. It hints at the 'includeCss' parameter via 'optional CSS rule usage tracking' and the 'action' parameter via 'Start or stop', but does not mention the required 'sessionId' or 'targetSessionId' parameters, leaving their purposes unclear.

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's function with specific verbs ('Start or stop') and a specific resource ('precise JavaScript coverage and optional CSS rule usage tracking'). It distinguishes this from sibling performance tools by focusing on coverage recording rather than metrics, heap snapshots, or tracing.

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 no guidance on when to use this tool versus alternatives like performance_trace or profiler_cpu. It implies usage for coverage recording but does not state context, prerequisites, or exclusions, leaving the agent without clear selection criteria.

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