MCP servers · Slack · MCP server
Connect Codex CLI to Slack
One line gives Codex CLI your Slack account as tools: 45 endpoints, send message, channels, threads, called with your own connection. No key in the prompt, a receipt for every call, revoke Codex CLI's access alone any time.
Three steps
- Create a free 0n3 account and connect Slack. Paste a key or sign in; it lands in your vault, encrypted.
- Install 0n3 into Codex CLI. OpenAI's terminal agent reads 0n3 over Streamable HTTP with a token from your environment.
- Ask Codex CLI: whoami. Then: "Send a message in Slack".
Put the token in your environment
export ON3_TOKEN="<your 0n token>"
Add it to your shell profile so Codex finds it next time.
The line above carries a placeholder; 0n3.app/install mints a real key named for Codex CLI and fills it in.
What Codex CLI can then do in Slack
Send message · Post, update, delete, and schedule messages7
Send a message
POST /chat.postMessageUpdate a message
POST /chat.updateDelete a message
POST /chat.deleteSchedule a message
POST /chat.scheduleMessagePin message
POST /pins.addUnpin message
POST /pins.removeSearch messages
GET /search.messagesChannels · Full channel lifecycle management13
List channels
GET /conversations.listCreate a channel
POST /conversations.createArchive a channel
POST /conversations.archiveUnarchive channel
POST /conversations.unarchiveRename channel
POST /conversations.renameSet a channel topic
POST /conversations.setTopicSet a channel purpose
POST /conversations.setPurposeInvite a to channel
POST /conversations.inviteKick from channel
POST /conversations.kickChannel history
GET /conversations.historyChannel info
GET /conversations.infoJoin channel
POST /conversations.joinThreads · Thread replies and conversation management2
Reply a to thread
POST /chat.postMessageGet thread replies
GET /conversations.repliesUsers · List users, get profiles, set status4
List users
GET /users.listGet an user
GET /users.infoGet an user profile
GET /users.profile.getSet an user status
POST /users.profile.setFiles · Upload, list, delete, and share files5
Upload a file
POST /files.uploadList files
GET /files.listDelete a file
POST /files.deleteShare file
POST /files.sharedPublicURLSearch files
GET /search.filesReactions · Emoji reactions on messages3
Add a reaction
POST /reactions.addRemove a reaction
POST /reactions.removeList reactions
GET /reactions.getSlack in other AI clients
Claude Code + SlackMCP server + skillClaude (desktop & claude.ai) + SlackconnectorChatGPT + Slackconnector · GPT actionGemini CLI + SlackMCP serverCursor + SlackMCP serverVS Code (Copilot) + SlackMCP serverWindsurf + SlackMCP server