fetch_online_metadata

Fetch high-quality book metadata from online sources (Amazon, Google, etc.). Returns metadata in OPF (XML) format.

SERVERCalibre SOURCE2b3pro/calibre-mcp

Low RISK CLASS

Category Read

Parameters 00 required

Recommended Allowedsee the rule below

Registry record Grade B, identity unverified Pull the record →

This record as markdown: /tools/2b3pro-calibre-mcp/fetch-online-metadata.md

WHAT IT DOES

What fetch_online_metadata does on Calibre

AI agents call fetch_online_metadata to retrieve information from Calibre without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

RISK

Why fetch_online_metadata is rated Low

This tool queries external online sources (Amazon, Google, etc.) and returns metadata in a read-only format. It does not modify the local library or any external data. The only concern is outbound network requests to third-party services, which is minor. Severity is low as misuse would at most result in unnecessary external queries.

From the tool's definition 'Fetch high-quality book metadata from online sources' and 'Returns metadata in OPF (XML) format' — retrieves data from external sources with no side effects described

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs fetch_online_metadata safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Calibre, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For fetch_online_metadata, this is the rule to start with:

fetch_online_metadata Allowed

fetch_online_metadata is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "fetch_online_metadata": {}
  }
}

ALLOW ONLY THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Calibre, apply this rule, and every fetch_online_metadata call is checked against it from then on.

FAQ

Questions about fetch_online_metadata

What does the fetch_online_metadata tool do? +

Fetch high-quality book metadata from online sources (Amazon, Google, etc.). Returns metadata in OPF (XML) format. It is categorised as a Read tool in the Calibre MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on fetch_online_metadata? +

Register the Calibre MCP server in PolicyLayer and add a rule for fetch_online_metadata: 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 Calibre. Nothing to install.

What risk level is fetch_online_metadata? +

fetch_online_metadata is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit fetch_online_metadata? +

Yes. Add a rate_limit block to the fetch_online_metadata 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.

How do I block fetch_online_metadata completely? +

Set action: deny in the PolicyLayer policy for fetch_online_metadata. 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.

What MCP server provides fetch_online_metadata? +

fetch_online_metadata is provided by the Calibre MCP server (2b3pro/calibre-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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