How to integrate Missive MCP with Codex

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

Missive logoMissive
Api Key

Missive is a collaborative email and chat app for teams to manage conversations and tasks together. It helps streamline team inboxes, shared labels, and internal discussion in one place.

40 Tools

Introduction

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

Also integrate Missive 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 Missive 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 Missive MCP server, and what's possible with it?

The Missive MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Missive account. It provides structured and secure access to your team's shared inboxes and chat threads, so your agent can perform actions like drafting emails, sending messages, generating reports, and managing team communication on your behalf.

  • Automated message drafting and scheduling: Let your agent create and save email, SMS, WhatsApp, or live chat drafts for later editing or scheduled sending.
  • Instant message sending in conversations: Have your agent send new messages directly to any Missive conversation, keeping your team in the loop in real time.
  • Team and user management: Effortlessly list all teams and their members, or pull a full directory of users in your Missive organization for easy coordination and task assignment.
  • Analytics report generation: Direct your agent to create detailed analytics reports across time ranges and filters, helping your team track productivity and engagement.
  • Webhook automation setup: Enable your agent to create or delete webhook subscriptions, so you can automate notifications and integrations with other tools as needed.

Conclusion

You've successfully integrated Missive with Codex using Composio's MCP server. Now you can interact with Missive 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 Missive 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 Missive operations
  • Explore cross-app workflows by connecting more toolkits
  • Build automation scripts that leverage Codex's AI capabilities
TOOLS

Supported Tools

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

Create Analytics Report

Tool to create an analytics report.

Create Missive Contacts

Tool to create one or more contacts in a Missive contact book.

Create Draft

Tool to create a new draft in Missive.

Create Missive Post

Tool to create a post in a Missive conversation.

Create Canned Response

Tool to create one or more canned responses (templates) in Missive.

Create Shared Label

Tool to create one or more shared labels at the organization level.

Create Missive Task

Tool to create a task in Missive.

Create Team

Tool to create a new team in an organization.

Create Webhook

Tool to create a webhook subscription.

Delete Draft

Tool to delete a draft from a conversation by draft ID.

Delete Post

Tool to delete a post from a conversation by post ID.

Delete Saved Responses

Tool to delete one or more saved responses by ID.

Delete Webhook

Tool to delete a webhook subscription by webhook ID.

Get Analytics Report

Tool to fetch a completed analytics report using its ID.

Get Missive Contact

Tool to fetch a specific contact using the contact ID.

Get Missive Conversation

Tool to fetch full conversation metadata (assignees/users/labels/team/org) for a specific conversation ID.

List Conversation Messages

Tool to list messages belonging to a Missive conversation (newest first).

Get Missive Message

Tool to fetch full message details including headers, HTML body, and attachments.

Get Missive Response

Tool to fetch a specific saved response using the response ID.

Get Missive Task

Tool to get a single task by ID with full details including assignees, team, and conversation info.

List Missive Contact Books

Tool to list contact books the authenticated user has access to.

List Missive Contact Groups

Tool to list contact groups or organizations linked to a contact book.

List Missive Contacts

Tool to list contacts from a contact book.

List Conversation Comments

Tool to list comments in a Missive conversation ordered from newest to oldest.

List Conversation Drafts

Tool to list draft messages in a Missive conversation (newest first).

List Conversation Posts

Tool to list posts in a Missive conversation ordered by newest first.

List Missive Conversations

Tool to list conversations visible to the authenticated user ordered by newest activity first.

List Messages by Message-ID

Tool to fetch messages matching an email Message-ID header.

List Missive Organizations

Tool to list organizations the authenticated user is part of.

List Missive Saved Responses

Tool to list saved responses (canned responses/templates) for the authenticated user.

List Missive Shared Labels

Tool to list shared labels (organization-level labels) available to the authenticated user.

List Missive Tasks

Tool to list tasks accessible to the authenticated user.

List Missive Teams

Tool to list all teams.

List Missive Users

Tool to list all users.

Merge Missive Conversations

Tool to merge multiple conversations into one.

Update Missive Contact

Tool to update one or more contacts in Missive.

Update Saved Response

Tool to update one or more saved responses in Missive.

Update Shared Labels

Tool to update one or more shared labels in Missive.

Update Missive Task

Tool to update an existing task's attributes in Missive.

Update Missive Team

Tool to update one or more teams in Missive.

FAQ

Frequently asked questions

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

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 Missive tools.

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

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