css_coverage_start

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

Without annotations, the description carries the full burden. It discloses that tracking is ongoing until css_coverage_stop is called, and that the result identifies unused rules. It doesn't mention whether calling start again resets tracking, but for a simple start tool this is adequate.

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 short sentences that are front-loaded with the action and provide the follow-up step. No wasted 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?

For a simple start tool with no parameters and no output schema, the description fully explains the tool's role and how to complete the flow. It's complete.

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, so the description has nothing to add. Per the scoring baseline for 0-parameter tools, this is solid.

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 'Start tracking CSS rule usage' with a specific verb and resource. It also names the complementary stop tool, distinguishing it from sibling tools like css_computed_style. The purpose is unambiguous.

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 instructs to browse around after starting and then call css_coverage_stop, giving a clear usage workflow. It doesn't explicitly name alternatives or exclusions, but the start/stop pairing is self-evident.

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