How to integrate Lokalise MCP with Pydantic AI

This guide walks you through connecting Lokalise to Pydantic AI using the Composio tool router. By the end, you'll have a working Lokalise agent that can list your projects, find untranslated keys, update translations, and review audit logs through natural language commands. This guide will help you understand how to give your Pydantic AI agent real control over a Lokalise account through Composio's Lokalise MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

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Lokalise is a translation and localization management platform for multilingual apps, websites, files, keys, and content. It helps teams ship localized products faster with organized workflows, contributors, and reviews.

10 Tools

Introduction

This guide walks you through connecting Lokalise to Pydantic AI using the Composio tool router. By the end, you'll have a working Lokalise agent that can list your projects, find untranslated keys, update translations, and review audit logs through natural language commands.

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

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

Also integrate Lokalise with

OpenAI Agents SDKClaude Agent SDKClaude CodeClaude CoworkCodexOpenClawHermesCLIGoogle 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 Lokalise
  • 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 Lokalise 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 Lokalise MCP server, and what's possible with it?

The Lokalise MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Lokalise account. It provides structured and secure access to your localization projects, branches, languages, keys, translations, and audit logs, so your agent can explore projects, manage keys, review translations, update localized content, and inspect team activity on your behalf.

  • Project and branch discovery: Have your agent list available localization projects and their branches so you can quickly find the content you need.
  • Language and translation review: Instruct your agent to check configured project languages and find translations by language, review state, task, or quality issue.
  • Translation updates: Let the agent revise translated content and update its review or status flags within a project or branch.
  • Localization key management: Direct your agent to search, create, update, or permanently delete localization keys, including their translations, metadata, review flags, and custom statuses.
  • Team activity auditing: Have your agent retrieve recent team audit events so you can inspect changes and localization activity.

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 Lokalise
  • 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 Lokalise
  • MCPServerStreamableHTTP connects to the Lokalise 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 Lokalise
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["lokalise"],
    )
    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 Lokalise 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
lokalise_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
agent = Agent(
    "openai:gpt-5",
    toolsets=[lokalise_mcp],
    instructions=(
        "You are a Lokalise assistant. Use Lokalise tools to help users "
        "with their requests. Ask clarifying questions when needed."
    ),
)
What's happening:
  • The MCP client connects to the Lokalise endpoint
  • The agent uses GPT-5 to interpret user commands and perform Lokalise 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 Lokalise.\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
  • Lokalise 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 Lokalise 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 Lokalise
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["lokalise"],
    )
    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
    lokalise_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
    agent = Agent(
        "openai:gpt-5",
        toolsets=[lokalise_mcp],
        instructions=(
            "You are a Lokalise assistant. Use Lokalise 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 Lokalise.\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 Lokalise through Composio's Tool Router. With this setup, your agent can perform real Lokalise 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 + Lokalise 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

Supported Tools

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

Create Keys

Create 1 to 500 keys in a Lokalise project or branch.

Delete Keys

Permanently delete one or more keys from a Lokalise project or branch.

List Audit Logs

List one page of team audit events in OCSF 1.

List Branches

List one page of branches for a Lokalise project.

List Keys

Search and return one cursor page of keys from a Lokalise project or branch.

List Project Languages

List one page of languages configured for a Lokalise project or, when branch_name is supplied, for a branch.

List Projects

List projects available to the connected Lokalise API token, optionally filtered by team or exact project names.

List Translations

Search and return one cursor page of translations from a Lokalise project or branch by language, review state, task, or QA issue.

Update Keys

Batch update keys and their translations, including key metadata, translation content, review flags, and custom statuses, in one Lokalise project or branch.

Update Translation

Update one translation's content and review or status flags in a Lokalise project or branch.

FRAMEWORKS

How to build Lokalise MCP Agent with another framework

OpenAI Agents SDK logo

OpenAI Agents SDK

Use Lokalise MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use Lokalise MCP with Claude Agent SDK

Claude Code logo

Claude Code

Use Lokalise MCP with Claude Code

Claude Cowork logo

Claude Cowork

Use Lokalise MCP with Claude Cowork

Codex logo

Codex

Use Lokalise MCP with Codex

OpenClaw logo

OpenClaw

Use Lokalise MCP with OpenClaw

Hermes logo

Hermes

Use Lokalise MCP with Hermes

CLI logo

CLI

Use Lokalise MCP with CLI

Google ADK logo

Google ADK

Use Lokalise MCP with Google ADK

LangChain logo

LangChain

Use Lokalise MCP with LangChain

Vercel AI SDK logo

Vercel AI SDK

Use Lokalise MCP with Vercel AI SDK

Mastra AI logo

Mastra AI

Use Lokalise MCP with Mastra AI

LlamaIndex logo

LlamaIndex

Use Lokalise MCP with LlamaIndex

CrewAI logo

CrewAI

Use Lokalise MCP with CrewAI

FAQ

Frequently asked questions

With a standalone Lokalise MCP server, the agents and LLMs can only access a fixed set of Lokalise tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Lokalise 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 Lokalise tools.

Yes, absolutely. You can configure which Lokalise 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 Lokalise data and credentials are handled as safely as possible.

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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.

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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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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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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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