validate_html
Check HTML for a page, a label, a description or a post before sending it, without Moodle, and approximately: only Moodle knows exactly what its cleaning keeps. Reports, with their lines, parse errors and tags left open, what Moodle's cleaning removes (scripts, styles, frames, forms, event attrib...
This record as markdown: /tools/falkenslab-moodle-mcp/validate-html.md
What validate_html does on Moodle
AI agents call validate_html to retrieve information from Moodle without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
file | string | — | Or an absolute path to a local HTML file |
text | string | — | The HTML |
embed | array | — | The local files you'll embed, as the content tools take them |
Parameters from the server's own tool schema.
Why validate_html is rated Low
Even though validate_html only reads data, uncontrolled read access leaks sensitive information and racks up API costs: an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.
Risk signalsAccepts file system path (file)
Attacks that exploit this kind of access
The rule that runs validate_html safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Moodle, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For validate_html, this is the rule to start with:
validate_html 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 Moodle, apply this rule, and every validate_html call is checked against it from then on.
Questions about validate_html
Check HTML for a page, a label, a description or a post before sending it, without Moodle, and approximately: only Moodle knows exactly what its cleaning keeps. Reports, with their lines, parse errors and tags left open, what Moodle's cleaning removes (scripts, styles, frames, forms, event attributes such as onclick, javascript: links), files the HTML names that are neither URLs nor in embed, and embed files that don't exist or the HTML doesn't name. Give embed as you would to the content tool. It is categorised as a Read tool in the Moodle MCP Server, which means it retrieves data without modifying state.
validate_html accepts 3 parameters: file, text, embed. The full parameter table on this page comes from the server's own tool schema.
Register the Moodle MCP server in PolicyLayer and add a rule for validate_html: 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 Moodle. Nothing to install.
validate_html 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 validate_html 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 validate_html. 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.
validate_html is provided by the Moodle MCP server (@falkenslab/moodle-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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