What exactly is a DOI and why is CrossRef important?

A Digital Object Identifier (DOI) is a unique, permanent identifier assigned to every published scholarly work — like a social security number for academic papers. CrossRef maintains the world's largest DOI registry with 140M+ records, making it the authoritative source for bibliographic metadata across all publishers globally.

Is authentication or registration required to use this server?

No. CrossRef's public API is free and open without authentication. Adding a polite email in the User-Agent header (which this server does automatically) grants access to the 'polite pool' with significantly faster response times.

What types of scholarly works can I find through CrossRef?

CrossRef covers virtually every type of scholarly output: journal articles, book chapters, conference proceedings, preprints, datasets, dissertations, and technical reports. It aggregates metadata from 20,000+ publishers including Elsevier, Springer Nature, Wiley, Oxford University Press, and thousands of smaller publishers worldwide.

CrossRef MCP Server for Google ADK 3 tools — connect in under 2 minutes

Name: CrossRef
Availability: InStock
Author: Vinkius

google.github.io/adk-docs/tools/mcp-tools

Built by Vinkius GDPR 3 Tools SDK

Google Agent Development Kit (ADK) is Google's framework for building production AI agents. Add CrossRef as an MCP tool provider through Vinkius and your ADK agents can call every tool with full schema introspection.

Get MCP Server for AI Agents

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Vinkius supports streamable HTTP and SSE.

python

from google.adk.agents import Agent
from google.adk.tools.mcp_tool import McpToolset
from google.adk.tools.mcp_tool.mcp_session_manager import (
    StreamableHTTPConnectionParams,
)

# Your Vinkius token. get it at cloud.vinkius.com
mcp_tools = McpToolset(
    connection_params=StreamableHTTPConnectionParams(
        url="https://edge.vinkius.com/[YOUR_TOKEN_HERE]/mcp",
    )
)

agent = Agent(
    model="gemini-2.5-pro",
    name="crossref_agent",
    instruction=(
        "You help users interact with CrossRef "
        "using 3 available tools."
    ),
    tools=[mcp_tools],
)

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About CrossRef MCP Server

Give your AI agent direct access to the world's largest registry of scholarly metadata — 140M+ records spanning every DOI ever assigned across all scientific publishers.

Google ADK natively supports CrossRef as an MCP tool provider. declare Vinkius Edge URL and the framework handles discovery, validation, and execution automatically. Combine 3 tools with Gemini's long-context reasoning for complex multi-tool workflows, with production-ready session management and evaluation built in.

What you can do

Universal Search — Find any published work across journals, books, conference papers, datasets, and dissertations using free-text queries
DOI Resolution — Instant metadata lookup for any DOI with title, complete author list, journal, year, type, and citation count
Author Discovery — Search for all publications by a specific researcher name across all major publishers simultaneously

The CrossRef MCP Server exposes 3 tools through the Vinkius. Connect it to Google ADK in under two minutes — no API keys to rotate, no infrastructure to provision, no vendor lock-in. Your configuration, your data, your control.

How to Connect CrossRef to Google ADK via MCP

Follow these steps to integrate the CrossRef MCP Server with Google ADK.

Install Google ADK

Run pip install google-adk

Replace the token

Replace [YOUR_TOKEN_HERE] with your Vinkius token

Create the agent

Save the code above and integrate into your ADK workflow

Explore tools

The agent will discover 3 tools from CrossRef via MCP

Why Use Google ADK with the CrossRef MCP Server

Google ADK provides unique advantages when paired with CrossRef through the Model Context Protocol.

Google ADK natively supports MCP tool servers. declare a tool provider and the framework handles discovery, validation, and execution

Built on Gemini models, ADK provides long-context reasoning ideal for complex multi-tool workflows with CrossRef

Production-ready features like session management, evaluation, and deployment come built-in. not bolted on

Seamless integration with Google Cloud services means you can combine CrossRef tools with BigQuery, Vertex AI, and Cloud Functions

CrossRef + Google ADK Use Cases

Practical scenarios where Google ADK combined with the CrossRef MCP Server delivers measurable value.

Enterprise data agents: ADK agents query CrossRef and cross-reference results with internal databases for comprehensive analysis

Multi-modal workflows: combine CrossRef tool responses with Gemini's vision and language capabilities in a single agent

Automated compliance checks: schedule ADK agents to query CrossRef regularly and flag policy violations or configuration drift

Internal tool platforms: build self-service agent platforms where teams connect their own MCP servers including CrossRef

CrossRef MCP Tools for Google ADK (3)

These 3 tools become available when you connect CrossRef to Google ADK via MCP:

get_crossref_doi

g. 10.1038/nature12373) and get complete metadata: title, all authors, journal, year, type, citation count, and abstract. Look up any scholarly work by its DOI

search_crossref

Every result includes DOI, citation count, and full bibliographic data. The world's largest DOI registry. Search 140M+ scholarly works across all scientific disciplines

search_crossref_author

Returns their publications sorted by relevance with citation counts. Find publications by a specific author

Example Prompts for CrossRef in Google ADK

Ready-to-use prompts you can give your Google ADK agent to start working with CrossRef immediately.

"Look up the paper with DOI 10.1038/nature12373 and show me all its details."

"Find all publications by Jennifer Doudna related to gene editing."

"Search CrossRef for the latest research on quantum computing error correction."

Troubleshooting CrossRef MCP Server with Google ADK

Common issues when connecting CrossRef to Google ADK through the Vinkius, and how to resolve them.

McpToolset not found

Update: pip install --upgrade google-adk

CrossRef + Google ADK FAQ

Common questions about integrating CrossRef MCP Server with Google ADK.

How does Google ADK connect to MCP servers?

Import the MCP toolset class and pass the server URL. ADK discovers and registers all tools automatically, making them available to your agent's tool-use loop.

Can ADK agents use multiple MCP servers?

Yes. Declare multiple MCP tool providers in your agent configuration. ADK merges all tool schemas and the agent can call tools from any server in a single turn.

Which Gemini models work best with MCP tools?

Gemini 2.0 Flash and Pro models both support function calling required for MCP tools. Flash is recommended for latency-sensitive use cases, Pro for complex reasoning.