Validate or autocomplete a Sefaria reference or title (e.g. "Genesis", "Rashi", "Berakhot"). Returns whether it is a valid reference/book and a list of completions. Keyless.
AI agents call lookup_ref to retrieve information from Mcp Sefaria without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
name | string | Yes | A partial title or reference to validate/autocomplete. |
Parameters from the server's own tool schema.
This tool retrieves and validates data from the Sefaria digital library without creating, modifying, deleting, or executing any operations. It is purely informational—autocompleting references and returning validation results. The 'Keyless' designation confirms no authentication/state modification. Severity is low because misuse would only result in spurious lookup results, with no blast radius.
From the tool's definition Tool description states it 'Validate or autocomplete a Sefaria reference or title' and 'Returns whether it is a valid reference/book and a list of completions.' These are query/lookup operations with no side effects.
Attacks that exploit this kind of access
Validate or autocomplete a Sefaria reference or title (e.g. "Genesis", "Rashi", "Berakhot"). Returns whether it is a valid reference/book and a list of completions. Keyless. It is categorised as a Read tool in the Mcp Sefaria MCP Server, which means it retrieves data without modifying state.
lookup_ref accepts 1 parameter: name. Required: name. The full parameter table on this page comes from the server's own tool schema.
Register the Mcp Sefaria MCP server in PolicyLayer and add a rule for lookup_ref: 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 Mcp Sefaria. Nothing to install.
lookup_ref 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 lookup_ref 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 lookup_ref. 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.
lookup_ref is provided by the Mcp Sefaria MCP server (pipeworx-io/mcp-sefaria). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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