CONNECT SYSTEM ONE MCP

Small decisions.
Ready for your agent.

Already have the System One plugin or MCP? Copy the prompt below. Your agent will check for it first.

Where do you use your agent?

CHATGPT · WEB

Add a custom MCP connection.

In ChatGPT Settings, open Security and login and enable Developer mode, if your account permits it.
Open ChatGPT Plugins, select the plus button, and name the connection System One MCP.
Use the remote URL below and choose OAuth. Verify your email in the browser, then review and approve the requested services.
Start a new chat, enable the connection from the tools menu, and paste your recipe prompt.

Custom MCP access depends on your account and workspace policy. This setup creates a custom connection; System One has not been published in the ChatGPT directory.

Official ChatGPT setup ↗

CURSOR · DESKTOP

Add the server, then sign in.

Cursor supports remote HTTP MCP and browser OAuth. Use its install link, review the configuration, and complete email sign-in and consent.

Add System One to Cursor ↗

Or merge this server into your existing MCP configuration. Keep your other servers.

{
  "mcpServers": {
    "system-one": {
      "url": "https://cloud.systemoneengine.com/mcp"
    }
  }
}

An install link adds configuration. Check that Cursor reports a successful connection before running a recipe.

Official Cursor MCP guide ↗

CLAUDE CODE · TERMINAL

Connect over HTTP.

claude mcp add --transport http system-one https://cloud.systemoneengine.com/mcp

Open /mcp inside Claude Code, choose System One, and authenticate in your browser. Then paste the recipe prompt.

This command applies to Claude Code. Other Claude surfaces have their own connector settings and access policies.

Official Claude Code guide ↗

CODEX · APP / CLI

Register the remote MCP.

codex mcp add system-one --url https://cloud.systemoneengine.com/mcp
codex mcp login system-one

Complete email sign-in and review the OAuth permissions in your browser. Return to Codex and use the recipe prompt.

Official Codex MCP guide ↗

Remote MCP URL

Instructions reviewed September 20, 2026 against official documentation. Protocol testing is separate from a successful connection in your agent account.

YOUR FIRST TASK

Let your agent check the setup.

This prompt discovers an existing connection first, then helps you connect if needed.

Help me use System One MCP for a useful bounded decision in our current task.

First inspect your available tools and installed plugins/skills for System One, sysone or System One Engine. If a compatible connection already exists, reuse it and call sysone_status. Do not install a duplicate. If tools are discoverable on demand, search for them before concluding they are unavailable.

If no connection is available, help me add the remote System One MCP at https://cloud.systemoneengine.com/mcp using this agent's supported MCP settings. Setup instructions: https://systemoneengine.com/connect/. I will verify my email and approve OAuth in my browser. Do not request my email code, provider key or access token in chat. Do not claim you connected until a tool call succeeds. If this account cannot add a custom MCP, explain the limitation and offer a supported client or the local setup.

Once connected, use sysone_patterns to find the relevant recipe, then follow its actual input schema and policy. Use only the evidence and options available in this task. Batch independent questions about the same state where useful. Send only the minimum relevant context and no secrets. Retain original evidence and uncertainty; a model decision is not permission to act. Use the result to continue the task yourself. If a deterministic rule is sufficient or delegation adds no value, skip the model call. Do not retry automatically or continue after the allowance is exhausted.

Report the decision, its limits, and any measured latency/usage. Do not invent token savings or treat a lower model probability as calibrated confidence.

Open your hosted dashboard →

Free preview includes up to $1 of Jev usage per UTC month. Your agents share one allowance. No payment card, no automatic overages.

Small decisions.Ready for your agent.

Add a custom MCP connection.

Add the server, then sign in.

Connect over HTTP.

Register the remote MCP.

Use remote MCP with OAuth.

Small decisions.
Ready for your agent.