collect_css_class_names
Collect all class names from a specified stylesheet. Args: stylesheet_id: ID of the stylesheet to analyse Returns: List of all CSS class names found in the stylesheet
This record as markdown: /tools/benjaminr-chrome-devtools-mcp/collect-css-class-names.md
What collect_css_class_names does on Chrome Devtools
AI agents call collect_css_class_names to retrieve information from Chrome Devtools without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Why collect_css_class_names is rated Low
This tool performs read-only analysis of CSS stylesheet content. It retrieves and returns class name information without modifying, executing code, deleting data, or causing any irreversible changes. The operation is analogous to querying or fetching static data from a resource.
From the tool's definition Tool description explicitly states it 'Collect[s] all class names from a specified stylesheet' and 'Returns: List of all CSS class names found in the stylesheet'. This is a pure data retrieval operation with no side effects.
Attacks that exploit this kind of access
The rule that runs collect_css_class_names safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Chrome Devtools, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For collect_css_class_names, this is the rule to start with:
collect_css_class_names is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Chrome Devtools, apply this rule, and every collect_css_class_names call is checked against it from then on.
Questions about collect_css_class_names
Collect all class names from a specified stylesheet. Args: stylesheet_id: ID of the stylesheet to analyse Returns: List of all CSS class names found in the stylesheet. It is categorised as a Read tool in the Chrome Devtools MCP Server, which means it retrieves data without modifying state.
Register the Chrome Devtools MCP server in PolicyLayer and add a rule for collect_css_class_names: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Chrome Devtools. Nothing to install.
collect_css_class_names is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the collect_css_class_names rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for collect_css_class_names. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
collect_css_class_names is provided by the Chrome Devtools MCP server (benjaminr/chrome-devtools-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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