Apply custom CSS overrides to the blog theme
AI agents use crow_blog_customize_theme to create or update resources in Crow — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Crow environment.
This tool modifies the blog's visual theme by applying CSS overrides. It's a write operation that changes configuration/appearance data. While it could be misused to inject malicious CSS, it is reversible (CSS can be changed back), placing it in the Write category. Medium severity because a malicious actor could use it to deface the blog or inject UI-based attacks.
From the tool's definition Apply custom CSS overrides to the blog theme
Documented attack patterns abuse exactly the kind of access crow_blog_customize_theme gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Crow, and nothing reaches the server without passing your rules. This is the rule we recommend for crow_blog_customize_theme:
{
"version": "1",
"default": "deny",
"tools": {
"crow_blog_customize_theme": {
"limits": [
{
"counter": "crow_blog_customize_theme_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
} crow_blog_customize_theme stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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Apply custom CSS overrides to the blog theme. It is categorised as a Write tool in the Crow MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Crow MCP server in PolicyLayer and add a rule for crow_blog_customize_theme: 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 Crow. Nothing to install.
crow_blog_customize_theme is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the crow_blog_customize_theme 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 crow_blog_customize_theme. 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.
crow_blog_customize_theme is provided by the Crow MCP server (kh0pper/crow). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Crow, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
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