browser_snapshot
The page in the browser tools' tab as an accessibility tree (roles, names, values), with a ref per element ([ref=e12]) for the other browser tools. By default the main region only (#region-main, where Moodle puts the content), or the whole page, or one element's subtree by ref. Cut at 30000 chara...
This record as markdown: /tools/falkenslab-moodle-mcp/browser-snapshot.md
What browser_snapshot does on Moodle
AI agents call browser_snapshot 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 |
|---|---|---|---|
ref | string | — | Only this element's subtree (from a previous snapshot) |
scope | string | — | "main" (default): Moodle's main region; "page": everything, navigation included |
Parameters from the server's own tool schema.
Why browser_snapshot is rated Low
Even though browser_snapshot 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.
Attacks that exploit this kind of access
The rule that runs browser_snapshot 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 browser_snapshot, this is the rule to start with:
browser_snapshot 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 browser_snapshot call is checked against it from then on.
Questions about browser_snapshot
The page in the browser tools' tab as an accessibility tree (roles, names, values), with a ref per element ([ref=e12]) for the other browser tools. By default the main region only (#region-main, where Moodle puts the content), or the whole page, or one element's subtree by ref. Cut at 30000 characters: snapshot a narrower part when cut. A fallback: use it only when no Moodle tool covers the task, and say which task, so a tool can be made for it. It is categorised as a Read tool in the Moodle MCP Server, which means it retrieves data without modifying state.
browser_snapshot accepts 2 parameters: ref, scope. 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 browser_snapshot: 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.
browser_snapshot 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 browser_snapshot 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 browser_snapshot. 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.
browser_snapshot 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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