How to integrate Workday MCP with Pydantic AI

This guide walks you through connecting Workday to Pydantic AI using the Composio tool router. By the end, you'll have a working Workday agent that can request vacation days for next week, check your current absence balance, find all open job postings i manage through natural language commands. This guide will help you understand how to give your Pydantic AI agent real control over a Workday account through Composio's Workday MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

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Workday is a cloud-based ERP platform for HR, finance, and workforce analytics. It streamlines employee management, payroll, and business operations in a single system.

84 Tools13 Triggers

Introduction

This guide walks you through connecting Workday to Pydantic AI using the Composio tool router. By the end, you'll have a working Workday agent that can request vacation days for next week, check your current absence balance, find all open job postings i manage through natural language commands.

This guide will help you understand how to give your Pydantic AI agent real control over a Workday account through Composio's Workday MCP server.

Before we dive in, let's take a quick look at the key ideas and tools involved.

Also integrate Workday with

ChatGPTOpenAI Agents SDKClaude Agent SDKClaude CodeClaude CoworkCodexOpenCodeCursorVS CodeOpenClawHermesCLIGoogle ADKLangChainVercel AI SDKMastra AILlamaIndexCrewAI

TL;DR

Here's what you'll learn:
  • How to set up your Composio API key and User ID
  • How to create a Composio Tool Router session for Workday
  • How to attach an MCP Server to a Pydantic AI agent
  • How to stream responses and maintain chat history
  • How to build a simple REPL-style chat interface to test your Workday workflows

What is Pydantic AI?

Pydantic AI is a Python framework for building AI agents with strong typing and validation. It leverages Pydantic's data validation capabilities to create robust, type-safe AI applications.

Key features include:

  • Type Safety: Built on Pydantic for automatic data validation
  • MCP Support: Native support for Model Context Protocol servers
  • Streaming: Built-in support for streaming responses
  • Async First: Designed for async/await patterns

What is the Workday MCP server, and what's possible with it?

The Workday MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Workday account. It provides structured and secure access to your HR, payroll, and recruiting data, so your agent can perform actions like managing time off, retrieving employee details, tracking job postings, and analyzing interview feedback on your behalf.

  • Automated time off management: Easily create new time off requests or check absence balances for yourself or others, making leave management effortless.
  • Employee data and profile retrieval: Have your agent fetch profile details for the current user or any specified worker to simplify onboarding and HR processes.
  • Comprehensive job posting insights: Instantly retrieve information about job postings, including descriptions and screening questionnaires, to aid recruiters and hiring managers.
  • Interview feedback analysis: Let your agent pull and summarize interview feedback entries to streamline debriefs and improve hiring decisions.
  • Access to holiday and leave events: Quickly get holiday schedules and leave status values for better workforce planning and scheduling.

What is the Composio tool router, and how does it fit here?

What is Composio SDK?

Composio's Composio SDK helps agents find the right tools for a task at runtime. You can plug in multiple toolkits (like Gmail, HubSpot, and GitHub), and the agent will identify the relevant app and action to complete multi-step workflows. This can reduce token usage and improve the reliability of tool calls. Read more here: Getting started with Composio SDK

The tool router generates a secure MCP URL that your agents can access to perform actions.

How the Composio SDK works

The Composio SDK follows a three-phase workflow:

  1. Discovery: Searches for tools matching your task and returns relevant toolkits with their details.
  2. Authentication: Checks for active connections. If missing, creates an auth config and returns a connection URL via Auth Link.
  3. Execution: Executes the action using the authenticated connection.

Step-by-step Guide

Step by step09 STEPS
1

Prerequisites

Before starting, make sure you have:
  • Python 3.9 or higher
  • A Composio account with an active API key
  • Basic familiarity with Python and async programming
2

Getting API Keys for OpenAI and Composio

OpenAI API Key
  • Go to the OpenAI dashboard and create an API key. You'll need credits to use the models, or you can connect to another model provider.
  • Keep the API key safe.
Composio API Key
  • Log in to the Composio dashboard.
  • Navigate to your API settings and generate a new API key.
  • Store this key securely as you'll need it for authentication.
3

Install dependencies

bash
pip install composio pydantic-ai python-dotenv

Install the required libraries.

What's happening:

  • composio connects your agent to external SaaS tools like Workday
  • pydantic-ai lets you create structured AI agents with tool support
  • python-dotenv loads your environment variables securely from a .env file
4

Set up environment variables

bash
COMPOSIO_API_KEY=your_composio_api_key_here
USER_ID=your_user_id_here
OPENAI_API_KEY=your_openai_api_key

Create a .env file in your project root.

What's happening:

  • COMPOSIO_API_KEY authenticates your agent to Composio's API
  • USER_ID associates your session with your account for secure tool access
  • OPENAI_API_KEY to access OpenAI LLMs
5

Import dependencies

python
import asyncio
import os
from dotenv import load_dotenv
from composio import Composio
from pydantic_ai import Agent
from pydantic_ai.mcp import MCPServerStreamableHTTP

load_dotenv()
What's happening:
  • We load environment variables and import required modules
  • Composio manages connections to Workday
  • MCPServerStreamableHTTP connects to the Workday MCP server endpoint
  • Agent from Pydantic AI lets you define and run the AI assistant
6

Create a Tool Router Session

python
async def main():
    api_key = os.getenv("COMPOSIO_API_KEY")
    user_id = os.getenv("USER_ID")
    if not api_key or not user_id:
        raise RuntimeError("Set COMPOSIO_API_KEY and USER_ID in your environment")

    # Create a Composio Tool Router session for Workday
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["workday"],
    )
    url = session.mcp.url
    if not url:
        raise ValueError("Composio session did not return an MCP URL")
What's happening:
  • We're creating a Tool Router session that gives your agent access to Workday tools
  • The create method takes the user ID and specifies which toolkits should be available
  • The returned session.mcp.url is the MCP server URL that your agent will use
7

Initialize the Pydantic AI Agent

python
# Attach the MCP server to a Pydantic AI Agent
workday_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
agent = Agent(
    "openai:gpt-5",
    toolsets=[workday_mcp],
    instructions=(
        "You are a Workday assistant. Use Workday tools to help users "
        "with their requests. Ask clarifying questions when needed."
    ),
)
What's happening:
  • The MCP client connects to the Workday endpoint
  • The agent uses GPT-5 to interpret user commands and perform Workday operations
  • The instructions field defines the agent's role and behavior
8

Build the chat interface

python
# Simple REPL with message history
history = []
print("Chat started! Type 'exit' or 'quit' to end.\n")
print("Try asking the agent to help you with Workday.\n")

while True:
    user_input = input("You: ").strip()
    if user_input.lower() in {"exit", "quit", "bye"}:
        print("\nGoodbye!")
        break
    if not user_input:
        continue

    print("\nAgent is thinking...\n", flush=True)

    async with agent.run_stream(user_input, message_history=history) as stream_result:
        collected_text = ""
        async for chunk in stream_result.stream_output():
            text_piece = None
            if isinstance(chunk, str):
                text_piece = chunk
            elif hasattr(chunk, "delta") and isinstance(chunk.delta, str):
                text_piece = chunk.delta
            elif hasattr(chunk, "text"):
                text_piece = chunk.text
            if text_piece:
                collected_text += text_piece
        result = stream_result

    print(f"Agent: {collected_text}\n")
    history = result.all_messages()
What's happening:
  • The agent reads input from the terminal and streams its response
  • Workday API calls happen automatically under the hood
  • The model keeps conversation history to maintain context across turns
9

Run the application

python
if __name__ == "__main__":
    asyncio.run(main())
What's happening:
  • The asyncio loop launches the agent and keeps it running until you exit

Complete Code

Here's the complete code to get you started with Workday and Pydantic AI:

python
import asyncio
import os
from dotenv import load_dotenv
from composio import Composio
from pydantic_ai import Agent
from pydantic_ai.mcp import MCPServerStreamableHTTP

load_dotenv()

async def main():
    api_key = os.getenv("COMPOSIO_API_KEY")
    user_id = os.getenv("USER_ID")
    if not api_key or not user_id:
        raise RuntimeError("Set COMPOSIO_API_KEY and USER_ID in your environment")

    # Create a Composio Tool Router session for Workday
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["workday"],
    )
    url = session.mcp.url
    if not url:
        raise ValueError("Composio session did not return an MCP URL")

    # Attach the MCP server to a Pydantic AI Agent
    workday_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
    agent = Agent(
        "openai:gpt-5",
        toolsets=[workday_mcp],
        instructions=(
            "You are a Workday assistant. Use Workday tools to help users "
            "with their requests. Ask clarifying questions when needed."
        ),
    )

    # Simple REPL with message history
    history = []
    print("Chat started! Type 'exit' or 'quit' to end.\n")
    print("Try asking the agent to help you with Workday.\n")

    while True:
        user_input = input("You: ").strip()
        if user_input.lower() in {"exit", "quit", "bye"}:
            print("\nGoodbye!")
            break
        if not user_input:
            continue

        print("\nAgent is thinking...\n", flush=True)

        async with agent.run_stream(user_input, message_history=history) as stream_result:
            collected_text = ""
            async for chunk in stream_result.stream_output():
                text_piece = None
                if isinstance(chunk, str):
                    text_piece = chunk
                elif hasattr(chunk, "delta") and isinstance(chunk.delta, str):
                    text_piece = chunk.delta
                elif hasattr(chunk, "text"):
                    text_piece = chunk.text
                if text_piece:
                    collected_text += text_piece
            result = stream_result

        print(f"Agent: {collected_text}\n")
        history = result.all_messages()

if __name__ == "__main__":
    asyncio.run(main())

Conclusion

You've built a Pydantic AI agent that can interact with Workday through Composio's Tool Router. With this setup, your agent can perform real Workday actions through natural language. You can extend this further by:
  • Adding other toolkits like Gmail, HubSpot, or Salesforce
  • Building a web-based chat interface around this agent
  • Using multiple MCP endpoints to enable cross-app workflows (for example, Gmail + Workday for workflow automation)
This architecture makes your AI agent "agent-native", able to securely use APIs in a unified, composable way without custom integrations.
TOOLS & TRIGGERS

Supported Tools and Triggers

Every Workday action and event your agent gets out of the box.

Create Business Title Change

Creates a business title change instance for a worker with the specified data.

Create Job Change

Tool to create a job change instance for a worker in Workday.

Create Payroll Inputs

Tool to create payroll inputs in Workday.

Create Time Off Request

Creates a time off request for the specified worker and initiates the business process.

Get Absence Balance

Retrieves balance information for a specific worker's absence plan.

Get Assignment Change Group Cost Centers

Retrieves cost center instances for organization assignment changes.

Get Assignment Change Group Jobs

Retrieves job instances for organization assignment changes.

Get Assignment Types

Retrieves assignment type values for job changes in Workday.

Get Business Title Change

Retrieves a business title change instance by ID.

Get Business Title Change For Worker

Tool to retrieve a business title change instance for a specific worker.

Get Candidate Availability Template

Tool to retrieve the candidate availability template version for a specific job posting.

Get Collection of Jobs

Tool to retrieve a paginated collection of jobs from Workday Staffing system.

Get Collection of Payroll

Tool to retrieve a collection of payroll inputs from Workday.

Get Company Insider Types

Retrieves company insider types from Workday Staffing API.

Get Contingent Worker Types

Tool to retrieve contingent worker types from Workday staffing API.

Get Country Info

Retrieves detailed information about a specific country from Workday.

Get Currencies

Retrieves currency instances for job changes in Workday.

Get Current User

Retrieves the current authenticated worker's profile information from Workday.

Get Grants

Retrieves grant instances for organization assignment changes.

Get Headcount Options

Retrieves headcount option instances that can be used as values for other endpoint parameters.

Get History Instance for Worker

Tool to retrieve a specific history instance for a worker.

Get History Items for Worker

Tool to retrieve a collection of history items for a specific worker.

Get Holiday Events

Returns the holiday events for the specified workers and time period.

Get Interview

Tool to retrieve detailed information about a specific interview from Workday Recruiting.

Get Interview Feedback

Retrieves interview feedback for the specified interview ID from Workday Recruiting API.

Get Job By ID

Tool to retrieve detailed information about a single job instance by its ID.

Get Job Change Frequencies

Retrieves frequency instances for job changes in Workday.

Get Job Change Location Info

Tool to retrieve location information for a specific job change in Workday.

Get Job Change Position

Retrieves position details for a specific job change in Workday Staffing API.

Get Job Change Reason Instance

Retrieves a job change reason instance from Workday.

Get Job Change Reasons

Retrieves a collection of job change reasons from Workday.

Get Job Change Reason Values

Retrieves job change reason instances that can be used as values for other staffing endpoint parameters.

Get Job Changes Group Templates

Retrieves job changes group template instances in Workday.

Get Job Changes Job Values

Retrieves job instances that can be used as values for job changes parameters.

Get Job Changes Worker Values

Retrieves worker instances that can be used as values for job changes parameters.

Get Job Classifications

Retrieves job classification instances for job changes in Workday.

Get Job Posting

Retrieves detailed information about a specific job posting including job description.

Get Job Posting Questionnaire

Retrieves screening questions and questionnaires associated with a specific job posting.

Get Job Profiles Values

Retrieves job profile instances from Workday Staffing API.

Get Job Requisition Values

Retrieves job requisition instances that can be used as values for other endpoint parameters.

Get Job Workspace

Tool to retrieve a single workspace instance for a specific job.

Get Job Workspaces

Tool to retrieve a collection of workspaces for a specified job ID.

Get Leave Status Values

Get all available leave status values from Workday.

Get My Job Postings

Retrieves job postings assigned to the authenticated user (current recruiter).

Get Organization Assignment Business Units

Retrieves business unit instances for organization assignment changes.

Get Organization Assignment Customs

Retrieves custom organization assignment instances.

Get Organization Assignment Funds

Retrieves fund instances for organization assignment changes.

Get Organization Assignment Regions

Retrieves region instances for organization assignment changes.

Get Organization Assignment Workers

Retrieves worker instances for organization assignment changes.

Get Pay Group by Job ID

Retrieves the pay group for a specified job ID.

Get Payroll Input Instance

Retrieves detailed information for a single payroll input instance by ID.

Get Pay Slip Instance for Worker

Retrieves a specific pay slip instance for a worker.

Get Pay Slips for Worker

Retrieves a collection of pay slips for a specific worker.

Get Proposed Position Values

Retrieves proposed position instances that can be used as values for job changes parameters.

Get Prospect

Retrieves a single prospect instance for talent matching and best-fit analysis.

Get Prospect Educations

Retrieves the educational background of a prospect from Workday Recruiting API for talent matching and best-fit analysis.

Get Prospect Experiences

Retrieves the work experience of a prospect for talent matching and best-fit analysis.

Get Prospect Resume Attachments

Retrieves resume attachments for a specific prospect to help prepare for upcoming interviews.

Get Prospect Skills

Retrieves the skills of a prospect from Workday Recruiting API for talent matching and best-fit analysis.

Get Supervisory Organization Values

Retrieves supervisory organization instances that can be used as values for job changes parameters.

Get Time Off Entries for Worker

Retrieves a collection of time off entries for a specific worker.

Get Time Off Plans For Worker

Retrieves a collection of time off plans for a specific worker.

Get Time Off Status Values

Retrieves available time off status values from Workday.

Get Time Types

Retrieves time type values for job changes in Workday.

Get Worker Business Title Changes

Retrieves business title changes for a specific worker.

Get Worker Eligible Absence Types

Retrieves a collection of eligible absence types for the specified worker.

Get Worker Info

Retrieves detailed worker information including staffing data.

Get Worker Leaves of Absence

Retrieves the Leaves Of Absence for the specified worker using the working absenceManagement v1 API.

Get Workers Collection Staffing

Tool to retrieve workers and current staffing information from Workday.

Get Worker Service Dates

Tool to retrieve service dates for a specified worker from Workday Staffing API v6.

Get Worker Staffing Information

Tool to retrieve a worker's current staffing information from Workday.

Get Worker Time Off Details

Retrieves a collection of time off details for the specified worker.

Get Worker Types

Retrieves worker type instances that can be used as values for job changes parameters.

Get Worker Valid Time Off Dates

Retrieves valid time off dates for a worker, indicating when they are eligible to take time off.

Get Workspace Instances

Tool to retrieve workspace instances that can be used as prompt values for other Workday API parameters.

Get Work Study Awards

Retrieves work study award instances for job changes in Workday.

List Countries

Retrieves country values from Workday Recruiting API.

List Interviews

Retrieves a list of interviews with job requisition and recruiter assignment details.

List Job Postings

Retrieves a paginated list of job postings from Workday Recruiting system.

List Jobs

Retrieves a collection of jobs from Workday Staffing system.

Retrieve Worker Leave of Absence

Retrieves the leave of absence details for a specified worker.

Update An Existing Payroll

Tool to partially update an existing payroll input instance in Workday.

Update Job Change Business Title

Partially updates the business title for a specific job change.

Update Message Template By ID

Tool to update a message template in Workday by its ID.

FRAMEWORKS

How to build Workday MCP Agent with another framework

ChatGPT logo

ChatGPT

Use Workday MCP with ChatGPT

OpenAI Agents SDK logo

OpenAI Agents SDK

Use Workday MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use Workday MCP with Claude Agent SDK

Claude Code logo

Claude Code

Use Workday MCP with Claude Code

Claude Cowork logo

Claude Cowork

Use Workday MCP with Claude Cowork

Codex logo

Codex

Use Workday MCP with Codex

Cursor logo

Cursor

Use Workday MCP with Cursor

OpenClaw logo

OpenClaw

Use Workday MCP with OpenClaw

Hermes logo

Hermes

Use Workday MCP with Hermes

CLI logo

CLI

Use Workday MCP with CLI

Google ADK logo

Google ADK

Use Workday MCP with Google ADK

LangChain logo

LangChain

Use Workday MCP with LangChain

Vercel AI SDK logo

Vercel AI SDK

Use Workday MCP with Vercel AI SDK

Mastra AI logo

Mastra AI

Use Workday MCP with Mastra AI

LlamaIndex logo

LlamaIndex

Use Workday MCP with LlamaIndex

CrewAI logo

CrewAI

Use Workday MCP with CrewAI

OpenCode logo

OpenCode

Use Workday MCP with OpenCode

VS Code logo

VS Code

Use Workday MCP with VS Code

FAQ

Frequently asked questions

With a standalone Workday MCP server, the agents and LLMs can only access a fixed set of Workday tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Workday and many other apps based on the task at hand, all through a single MCP endpoint.

Yes, you can. Pydantic AI fully supports MCP integration. You get structured tool calling, message history handling, and model orchestration while Tool Router takes care of discovering and serving the right Workday tools.

Yes, absolutely. You can configure which Workday scopes and actions are allowed when connecting your account to Composio. You can also bring your own OAuth credentials or API configuration so you keep full control over what the agent can do.

All sensitive data such as tokens, keys, and configuration is fully encrypted at rest and in transit. Composio is SOC 2 Type 2 compliant and follows strict security practices so your Workday data and credentials are handled as safely as possible.

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Karan skipped his own birthday party to fix our critical issue. It was 10pm and he diverted his Waymo to help us instead. This really sets the bar — it shows the commitment you need when users rely on your software.

Harsha Gaddipati
Harsha Gaddipati
Co-founder, Slashy

A lot of students tell us that the moment their connected tools start talking to each other inside Opennote feels almost magical. The agent just knows them, and it's immensely helped keep new users on the platform.

Abhi Arya
Abhi Arya
Co-founder, Opennote

We chose Composio over Pipedream because it delivered depth where it mattered — niche tools and tricky edge cases other platforms simply ignored. That gave us confidence to scale without compromising.

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CEO, Zams

As a solo builder, shipping fast is life or death. The only way I can outcompete incumbents is by outmanoeuvring them. Getting bogged down managing agent auth would have been a death sentence.

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Founder, Extra Thursday

Before Composio, adding tool integrations was slow and resource-intensive. Each one could take weeks of engineering time, and maintaining them meant constantly keeping up with API changes.

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Founder & CEO, SwarmZero

With hands-on help from their founder, we integrated Gmail and Google Drive in just 30 minutes. This level of personal support and commitment is exactly what startups should strive for.

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Co-Founder, Ingram Technologies