AI agents call get_crossref_paper_by_doi 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 retrieves academic paper information from a public database (Crossref) based on a DOI parameter. It has no side effects beyond data retrieval. While the description is empty, the naming convention ('get_' prefix) and the server's stated purpose (searching/downloading papers) confirm Read category.
From the tool's definition Tool name 'get_crossref_paper_by_doi' indicates retrieval of academic paper metadata/content from Crossref by DOI identifier.
Documented attack patterns abuse exactly the kind of access get_crossref_paper_by_doi 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 get_crossref_paper_by_doi:
{
"version": "1",
"default": "deny",
"tools": {
"get_crossref_paper_by_doi": {}
}
}get_crossref_paper_by_doi is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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get_crossref_paper_by_doi. 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 get_crossref_paper_by_doi: 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.
get_crossref_paper_by_doi 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 get_crossref_paper_by_doi 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 get_crossref_paper_by_doi. 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.
get_crossref_paper_by_doi 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.
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63 Paper Search MCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.