Lookup a DOI via Unpaywall and return OA metadata. Unpaywall is DOI-centric and does not support generic keyword search. This tool extracts the first DOI from query and returns at most one record. Args: query: DOI string or text containing a DOI. max_results: Kept for API consistency; Unpaywall r...
AI agents call search_unpaywall to retrieve information from Paper Search MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a simple read-only lookup operation against the Unpaywall service to retrieve publicly available open-access metadata for academic papers. It extracts a DOI from a query string and returns metadata—a classic retrieval operation with no side effects, no code execution, no data modification, and no destructive actions.
From the tool's definition Tool description states it 'Lookup a DOI via Unpaywall and return OA metadata' and 'returns at most one record'.
Documented attack patterns abuse exactly the kind of access search_unpaywall gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Paper Search MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for search_unpaywall:
{
"version": "1",
"default": "deny",
"tools": {
"search_unpaywall": {}
}
}search_unpaywall is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Lookup a DOI via Unpaywall and return OA metadata. Unpaywall is DOI-centric and does not support generic keyword search. This tool extracts the first DOI from query and returns at most one record. Args: query: DOI string or text containing a DOI. max_results: Kept for API consistency; Unpaywall returns max 1 record. Returns: List with one paper metadata dict when DOI is resolvable, else empty list. It is categorised as a Read tool in the Paper Search MCP MCP Server, which means it retrieves data without modifying state.
Register the Paper Search MCP server in PolicyLayer and add a rule for search_unpaywall: 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 Paper Search MCP. Nothing to install.
search_unpaywall 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 search_unpaywall 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 search_unpaywall. 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.
search_unpaywall is provided by the Paper Search MCP server (openags/paper-search-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 63 Paper Search MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
63 Paper Search MCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.