Retrieve computed CSS properties for a selected element, defaulting to layout-relevant styles so agents can inspect rendered page styling.
Return computed CSS for an element. Defaults to the layout-relevant set.
| Name | Required | Description | Default |
|---|---|---|---|
| tab_id | No | ||
| selector | Yes | ||
| properties | No |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden of behavioral disclosure. It states the default property set but omits whether this is read-only, what tab state or permissions are required, what the return shape looks like, and how tab_id defaults when omitted.
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 tight sentences, front-loaded with the action and followed by the default behavior. No filler or repetition.
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 3-parameter tool with no annotations and no output schema, the description is too sparse to ensure correct invocation. It omits tab_id behavior, properties syntax, return structure, and error conditions.
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 0%, so the description must explain all three parameters. It implicitly covers selector ('for an element') and properties default ('layout-relevant set'), but tab_id is never mentioned, leaving a key parameter undocumented.
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?
States a specific verb ('Return') and resource ('computed CSS for an element'), distinguishing it from DOM/HTML inspection siblings. It does not explicitly say how it differs from browser_dom or browser_explain_selector, so it stops short of a 5.
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 when-to-use guidance, no alternatives named, and no prerequisites such as needing an attached tab. The only usage hint is the default property set, which is behavioral rather than selection guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.