How to integrate Openai MCP with Codex

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Introduction

Codex is one of the most popular coding harnesses out there. And MCP makes the experience even better. With Openai MCP integration, you can draft, triage, summarise emails, and much more, all without leaving the terminal or the app, whichever you prefer.

Also integrate Openai with

Why use Composio?

Apart from a managed and hosted MCP server, you will get:

  • CodeAct: A dedicated workbench that allows GPT to write its code to handle complex tool chaining. Reduces to-and-fro with LLMs for frequent tool calling.
  • Large tool responses: Handle them to minimise context rot.
  • Dynamic just-in-time access to 20,000 tools across 1000+ other Apps for cross-app workflows. It loads the tools you need, so GPTs aren't overwhelmed by tools you don't need.

How to install Openai MCP in Codex

Run the setup command

Run this command in your terminal to add the Composio MCP server to Codex.

Terminal

It will initiate the authentication in a browser window, authorize Codex to access your Composio account.

Composio authentication page

(Optional) Authenticate with OAuth

To authenticate manually, run the login command to open a browser window and authorize Codex to access your Composio account.

bash
codex mcp login composio

Verify the connection

Run codex mcp list to confirm Composio appears as a registered MCP server.

bash
codex mcp list

Codex App

Codex App follows the same approach as VS Code.

  1. Click ⚙️ on the bottom left → MCP Servers → + Add servers → Streamable HTTP:
  2. Fill the header and Key fields with { "x-consumer-api-key" = "ck_*******" }.
  3. The Key is the Composio API key, that you can find on dashboard.composio.dev
  4. Click on Authenticate and authorize Codex to your Composio account and you're all set.
Codex App MCP setup
  1. Restart and verify if it's there in .codex/config.toml
bash
[mcp_servers.composio]
url = "https://connect.composio.dev/mcp"
http_headers = { "x-consumer-api-key" = "ck_*******" }

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

The Openai MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your OpenAI account. It provides structured and secure access to your models, assistants, files, threads, and fine-tuning jobs, so your agent can perform actions like managing assistants, handling conversations, uploading or organizing files, and working with OpenAI models on your behalf.

  • Assistant and conversation management: Quickly create, update, or delete OpenAI assistants and manage threads or messages for seamless conversational flows.
  • File uploads and organization: Let your agent upload new files, list all uploaded documents, or delete unnecessary files to keep your workspace tidy.
  • Model discovery and utilization: Effortlessly list all available OpenAI models—including vision and multimodal—and retrieve their details to choose the best fit for your tasks.
  • Fine-tuning job insights: View a complete list of your organization's fine-tune jobs and track their progress or review results as needed.
  • Thread and run management: Create, modify, or inspect threads and run steps to fully control and monitor interactive agent conversations.

Supported Tools & Triggers

Tools
Add Upload PartTool to add a part (chunk of bytes) to an Upload object.
Cancel batchTool to cancel an in-progress batch.
Cancel evaluation runTool to cancel an ongoing evaluation run.
Cancel ResponseTool to cancel a background model response by its ID.
Cancel RunTool to cancel a run that is currently in progress.
Cancel uploadTool to cancel an upload.
Compact ResponseTool to compact a conversation or response to reduce token usage.
Create Audio TranscriptionTool to transcribe audio files to text via OpenAI Audio Transcriptions API.
Create Audio TranslationTool to translate audio files to English text via OpenAI Audio Translations API.
Create BatchTool to create and execute a batch from an uploaded file of requests.
Create Chat CompletionTool to create a chat completion response from OpenAI models.
Create Completion (Legacy)Tool to generate text completions using OpenAI's legacy Completions API.
Create ContainerTool to create a new container with configurable memory, expiration, file access, and network policies.
Create Container FileTool to create a file in a container.
Create ConversationTool to create a new conversation for multi-turn interactions.
Create Conversation ItemsTool to create items in a conversation with the given ID.
Create EmbeddingsTool to generate text embeddings via the OpenAI embeddings endpoint.
Create EvalTool to create an evaluation structure for testing a model's performance.
Create Evaluation RunTool to create a new evaluation run for testing model configurations.
Create fine-tuning jobTool to create a fine-tuning job which begins the process of creating a new model from a given dataset.
Generate ImageTool to generate an image via the OpenAI Images API and return hosted image asset URL and metadata.
Edit ImageTool to create edited or extended images via OpenAI Images Edit API.
Create Image VariationTool to create a variation of a given image using the OpenAI Images API.
Create MessageTool to create a new message in a specific thread.
Create ModerationTool to classify text and/or image inputs for potentially harmful content via the OpenAI Moderation API.
Create Realtime CallTool to create a Realtime API call over WebRTC and receive the SDP answer needed to complete the peer connection.
Create Realtime Client SecretTool to create an ephemeral client secret for authenticating Realtime API connections.
Create Realtime SessionTool to create an ephemeral API token for client-side Realtime API applications.
Create Realtime Transcription SessionTool to create an ephemeral API token for realtime transcriptions via the Realtime API.
Create ResponseTool to generate a one-shot model response via the Responses API.
Create RunTool to create a run on a thread with an assistant.
Create SkillTool to create a skill from uploaded files.
Create Speech (TTS)Tool to generate text-to-speech audio using OpenAI's Audio API.
Create ThreadTool to create a new thread.
Create Thread And RunTool to create a thread and run it in one request.
Create UploadTool to create an intermediate Upload object for large file uploads.
Create Vector StoreTool to create a new vector store.
Create Vector Store FileTool to create a vector store file by attaching a File to a vector store.
Create vector store file batchTool to create a vector store file batch.
Create VideoTool to create a video using Sora models via the OpenAI Videos API.
Create Video RemixTool to create a video remix from an existing generated video using OpenAI's Video API.
Delete assistantTool to delete a specific assistant by its ID.
Delete chat completionTool to delete a stored chat completion by its ID.
Delete containerTool to delete a specific container by its ID.
Delete container fileTool to delete a file from a container.
Delete conversationTool to delete a conversation by its ID.
Delete conversation itemTool to delete an item from a conversation with the given IDs.
Delete evaluationTool to delete a specific evaluation by its ID.
Delete evaluation runTool to delete an evaluation run.
Delete fileTool to delete a file by its ID after confirming the target.
Delete messageTool to delete a message from a thread.
Delete responseTool to delete a model response with the given ID.
Delete skillTool to delete a specific skill by its ID.
Delete threadTool to delete a thread by its ID.
Delete Vector StoreTool to delete a vector store.
Delete Vector Store FileTool to delete a vector store file.
Delete videoTool to delete a video by its ID.
Download fileTool to download the contents of a specified file by its ID.
Download Video ContentTool to download video content (MP4) or preview assets from OpenAI Videos API.
Get Chat CompletionTool to retrieve a stored chat completion.
Get Chat Completion MessagesTool to retrieve messages from a stored chat completion.
Get ChatKit threadTool to retrieve a ChatKit thread by its ID.
Get Conversation ItemTool to retrieve a single item from a conversation.
Get EvalTool to retrieve an evaluation by ID.
Get Evaluation RunTool to retrieve an evaluation run by ID to check status and results.
Get Eval Run Output ItemTool to retrieve a specific output item from an evaluation run by its ID.
Get eval run output itemsTool to get a list of output items for an evaluation run.
Get Evaluation RunsTool to get a paginated list of runs for an evaluation.
Get Input Token CountsTool to calculate input token counts for OpenAI API requests.
Get MessageTool to retrieve a specific message from a thread by its ID.
Get ResponseTool to retrieve a model response by ID.
Get Run StepTool to retrieve a specific run step from an Assistants API run to inspect detailed execution progress, view tool calls, or check message creation.
Get Vector StoreTool to retrieve a vector store by its ID.
Get Vector Store FileTool to retrieve a file from a vector store.
Get Vector Store File BatchTool to retrieve a vector store file batch.
Get VideoTool to retrieve a video generation job by its unique identifier.
List AssistantsTool to list assistants to discover the correct assistant_id by name or metadata.
List BatchesTool to list your organization's batches.
List Chat CompletionsTool to list stored chat completions that were created with the `store` parameter set to true.
List ChatKit thread itemsTool to list ChatKit thread items.
List container filesTool to list files in a container.
List ContainersTool to list containers.
List Conversation ItemsTool to list all items for a conversation with the given ID.
List enginesTool to list available engines and their basic information.
List EvalsTool to list evaluations for a project.
List filesTool to retrieve a list of files uploaded to your organization/project context.
List Files in Vector Store BatchTool to list vector store files in a batch.
List fine-tunesTool to list your organization's fine-tuning jobs.
List fine-tuning job eventsTool to get status updates for a fine-tuning job.
List fine-tuning job checkpointsTool to list checkpoints for a fine-tuning job.
List Input ItemsTool to retrieve input items for a given response from the OpenAI Responses API.
List MessagesTool to list messages in an Assistants thread to fetch the assistant's generated outputs after a run completes.
List modelsTool to list available models scoped to the current account/organization — some public models may be absent due to permissions.
List RunsTool to list runs belonging to a thread.
List Run StepsTool to list run steps for an Assistants API run to track detailed execution progress, inspect tool calls, and view message creation events.
List SkillsTool to list skills.
List ChatKit ThreadsTool to list ChatKit threads with pagination and filtering.
List Vector Store FilesTool to list files in a vector store.
List Vector StoresTool to list vector stores to discover available vector stores by name or metadata.
List VideosTool to list all video generation jobs.
Modify AssistantTool to modify an existing assistant.
Modify MessageTool to modify an existing message's metadata in a thread.
Modify RunTool to modify a run's metadata.
Modify threadTool to modify an existing thread's metadata.
Modify Vector StoreTool to modify an existing vector store.
Retrieve assistantTool to retrieve details of a specific assistant.
Retrieve BatchTool to retrieve a batch by ID to check its status, progress, and results.
Retrieve containerTool to retrieve details of a specific container by its ID.
Retrieve container fileTool to retrieve metadata for a specific file in a container.
Retrieve container file contentTool to retrieve the content of a file within a container.
Retrieve engineTool to retrieve details of a specific engine.
Retrieve fileTool to retrieve information about a specific file.
Retrieve fine-tuning jobTool to retrieve information about a fine-tuning job.
Retrieve modelTool to retrieve details of a specific model, confirming its metadata (ownership, created date) and verifying access under your org — a model appearing in OPENAI_LIST_MODELS does not guarantee access.
Retrieve runTool to retrieve an Assistants run by ID to check status, errors, and usage.
Retrieve threadTool to retrieve metadata of a specific thread by its ID — does not include message bodies or assistant replies (those require a completed run and separate message listing).
Retrieve Vector Store File ContentTool to retrieve the parsed contents of a vector store file.
Run graderTool to run a grader to evaluate model performance on a given sample.
Search Vector StoreTool to search a vector store for relevant chunks based on a query and file attributes filter.
Submit Tool Outputs to RunTool to submit tool call outputs to continue a run that requires action.
Update Chat CompletionTool to update metadata for a stored chat completion.
Update ConversationTool to update a conversation's metadata.
Update EvalTool to update certain properties of an evaluation (name and metadata).
Update Vector Store File AttributesTool to update custom attributes on a vector store file.
Upload fileTool to upload a file for use across OpenAI endpoints.
Validate grader configurationTool to validate a grader configuration for fine-tuning jobs.

Conclusion

You've successfully integrated Openai with Codex using Composio's MCP server. Now you can interact with Openai directly from your terminal, VS Code, or the Codex App using natural language commands.

Key benefits of this setup:

  • Seamless integration across CLI, VS Code, and standalone app
  • Natural language commands for Openai operations
  • Managed authentication through Composio
  • Access to 20,000+ tools across 1000+ apps for cross-app workflows
  • CodeAct workbench for complex tool chaining

Next steps:

  • Try asking Codex to perform various Openai operations
  • Explore cross-app workflows by connecting more toolkits
  • Build automation scripts that leverage Codex's AI capabilities

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FAQ

What are the differences in Tool Router MCP and Openai MCP?

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

Can I use Tool Router MCP with Codex?

Yes, you can. Codex 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 Openai tools.

Can I manage the permissions and scopes for Openai while using Tool Router?

Yes, absolutely. You can configure which Openai 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.

How safe is my data with Composio Tool Router?

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 Openai data and credentials are handled as safely as possible.

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