css_matched_rules

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

With no annotations, the description carries the full burden. 'Get' clearly implies a read-only operation, and listing the types of rules returned provides useful behavioral context. However, it does not explicitly state non-destructiveness or any potential limitations.

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?

One concise, front-loaded sentence with no waste. Every word contributes meaning, and the structure is immediately scannable.

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 one-parameter getter with no output schema, the description sufficiently explains what is returned. It could add a note about read-only behavior or selector matching specifics, but overall it is complete enough for this low-complexity tool.

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 schema already fully documents the only parameter 'selector' with a clear description. The tool description adds no additional meaning beyond what the schema provides, and schema coverage is 100%, so baseline 3 applies.

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?

Uses the specific verb 'Get' and clearly identifies the resource: all CSS rules matching an element. Enumerates the rule categories included (inline, matched, inherited, pseudo-elements), which differentiates it from sibling tools like css_computed_style or css_background_colors by scope.

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 on when to use this tool versus alternatives. It does not mention any exclusions, prerequisites, or situations where another tool like css_computed_style or css_force_pseudo would be more appropriate.

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