Search academic papers from CrossRef database. CrossRef is a scholarly infrastructure organization that provides persistent identifiers (DOIs) for scholarly content and metadata. It's one of the largest citation databases covering millions of academic papers, journals, book...
Accepts freeform code/query input (query)
Part of the Paper Search MCP server. Enforce policies on this tool with Intercept, the open-source MCP proxy.
AI agents call search_crossref to retrieve information from Paper Search without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.
Even though search_crossref only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.
Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.
tools:
search_crossref:
rules:
- action: allowSee the full Paper Search policy for all 25 tools.
Agents calling read-class tools like search_crossref have been implicated in these attack patterns. Read the full case and prevention policy for each:
Other tools in the Read risk category across the catalogue. The same policy patterns (rate-limit, allow) apply to each.
Search academic papers from CrossRef database. CrossRef is a scholarly infrastructure organization that provides persistent identifiers (DOIs) for scholarly content and metadata. It's one of the largest citation databases covering millions of academic papers, journals, books, and other scholarly content. Args: query: Search query string (e.g., 'machine learning', 'climate change'). max_results: Maximum number of papers to return (default: 10, max: 1000). **kwargs: Additional search parameters: - filter: CrossRef filter string (e.g., 'has-full-text:true,from-pub-date:2020') - sort: Sort field ('relevance', 'published', 'updated', 'deposited', etc.) - order: Sort order ('asc' or 'desc') Returns: List of paper metadata in dictionary format. Examples: # Basic search search_crossref("deep learning", 20) # Search with filters search_crossref("climate change", 10, filter="from-pub-date:2020,has-full-text:true") # Search sorted by publication date search_crossref("neural networks", 15, sort="published", order="desc") . It is categorised as a Read tool in the Paper Search MCP Server, which means it retrieves data without modifying state.
Add a rule in your Intercept YAML policy under the tools section for search_crossref. You can allow, deny, rate-limit, or validate arguments. Then run Intercept as a proxy in front of the Paper Search MCP server.
search_crossref 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_crossref rule in your Intercept 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 Intercept policy for search_crossref. 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_crossref is provided by the Paper Search MCP server (adamamer20/paper-search-mcp-openai). Intercept sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Open source. One binary. Zero dependencies.
npx -y @policylayer/intercept