How to Use the Fieldly MCP in Pydantic AI
Build type-safe construction agents using Pydantic AI and the Fieldly MCP Server.
Works with every AI agent you already use
…and any MCP-compatible client
Connect Fieldly MCP to Pydantic AI
Create your Vinkius account to connect Fieldly to Pydantic AI and route execution through our secure gateway. The platform manages server hosting, runtime updates, and security layers. Configuration requires no manual server provisioning.
Runtime Validation for Construction ERP
Let's face it: construction data cannot tolerate silent errors. Pydantic AI guarantees that every payload returned by the Fieldly MCP Server matches your exact schema, failing loudly if `get_invoice` returns a malformed string or an unexpected null value. If the API structure changes, your agent throws a validation error immediately instead of processing a corrupt invoice. This protects your accounting system from bad data when running automated checks against `list_invoices`.
Strict Type Checks on MCP Server Work Items
When your agent schedules new tasks, type safety keeps the system stable. Pydantic AI validates the arguments for `create_work_item` before sending the request, ensuring that dates, user IDs, and descriptions conform to strict Python types. If the model attempts to pass a non-integer ID to `get_booking` or a missing field to `get_work_item`, the framework blocks the call at the boundary. This saves your API quota and prevents database corruption.
Model-Agnostic Validation
Run your field operations on any LLM while keeping your data validation intact. Whether you plug in Anthropic, OpenAI, or a local model, Pydantic AI enforces consistent schemas across all 11 tools, from `list_customers` to `list_articles`. This decoupling means you can swap the underlying model to optimize for speed or cost without rewriting your integrations. The agent will still reliably parse `list_users` and output clean, validated records every time.
Set up Fieldly MCP in Pydantic AI
Prerequisites
- Python 3.10+ installed
-
pydantic-ai-slim[fastmcp]package - Active Vinkius subscription with a valid endpoint token
- 1
Install Pydantic AI with FastMCP
Run
pip install "pydantic-ai-slim[fastmcp]". The FastMCP toolset replaces the deprecatedMCPServerHTTPclass with full protocol support. - 2
Configure the FastMCPToolset
Pass a JSON-style config dict to
FastMCPToolsetwith your Vinkius URL. Replace[YOUR_TOKEN_HERE]with your token from cloud.vinkius.com. Supports Streamable HTTP, SSE, and Stdio transports. - 3
Create and run your agent
Pass the toolset to
Agent(toolsets=[toolset])and callagent.run(). Swapopenai:gpt-4ofor any supported model — Anthropic, Google, Mistral, or Groq.
from pydantic_ai import Agent
from pydantic_ai.toolsets.fastmcp import FastMCPToolset
toolset = FastMCPToolset({
"mcpServers": {
"fieldly-mcp": {
"url": "https://edge.vinkius.com/[YOUR_TOKEN_HERE]/mcp"
}
}
})
agent = Agent(
"openai:gpt-4o",
toolsets=[toolset],
system_prompt="You have access to Fieldly tools.",
)
result = await agent.run("List recent Fieldly transactions")
print(result.output) Independent Platform Disclaimer: Vinkius is an independent platform and is not affiliated with, endorsed by, sponsored by, verified by, or otherwise authorized by Fieldly. All third-party trademarks, logos, and brand names are the property of their respective owners. Their use on this website is strictly for informational purposes to identify service compatibility and interoperability.
Why Choose Vinkius
Vinkius connects your tools to AI with real-time monitoring and automatic cost savings — all from one dashboard.
Real-time monitoring
Live
visibility into every interaction
Connect your favorite tools to your AI and see exactly what's happening — every request, every response, in real time.
Built-in savings
60%
lower AI costs
Vinkius compresses data between your apps and your AI automatically. Lower bills every month — no configuration required.
Single dashboard
One
place for every integration
Every tool your AI connects to, managed from a single screen. One account, complete control.
Common questions about Fieldly MCP in Pydantic AI
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