Builder MCP Server

The Builder MCP server exposes the same Workflow-building tool surface used by Flowgear's built-in tooling so that Workflows can be created and tested from outside the Console.

For most people, the easiest way to work with Builder MCP is from an IDE or editor. You keep the frontend in your local repository, and use Flowgear Workflows as the backend. If you prefer a more terminal-first or graphical way of working, Builder MCP can also work there when the coding agent supports it.

Set up the Builder MCP Server

The best way to get started is to use the Builder MCP Server to create a Flowgear app.

Use this Builder MCP URL:

https://your-environment-hostname.flowgear.net/mcp/builder

your-environment-hostname is the subdomain of the Environment you want to target.

Use flowgear as the server name in all commands. This must stay flowgear because the sample app's agents.md expects that name.

Choose your Coding Agent

OpenAI Codex

For most readers, the best place to use Codex with Builder MCP is the Codex IDE Extension for Visual Studio Code.

Install the Codex CLI. Then, verify the install:
```
codex --version
```

Add the Builder MCP Server from your project terminal:

codex mcp add flowgear --url https://your-environment-hostname.flowgear.net/mcp/builder

Authenticate by completing the browser sign-in flow:
- If OAuth is detected, codex mcp add should start the auth flow automatically.
- If it does not start automatically, run:
```
codex mcp login flowgear
```
Check that Codex can connect by sending a message such as list tools available in flowgear mcp server. You should see tools such as ListWorkflows and ListNodes.
Codex will usually ask for approvals while it works. Builder MCP often involves many tool calls, so review the current Codex approvals and security guidance and choose the permission mode that fits your environment. Only use full-access modes in isolated development environments, such as dedicated dev containers or VMs.
After setup, choose where you want to use Codex:
- Codex IDE Extension if you want the recommended editor-based option, with your files, terminal, and Builder MCP tools all in one place.
- Codex CLI if you prefer to work directly from the terminal, or if you are developing in a remote shell, container, or similar environment.
- Codex App if you want a standalone desktop workspace. We have verified that after you register and authenticate the flowgear MCP server from the CLI, the same server also appears in Codex App. You can then use /mcp in Codex App, but complete authentication from the CLI first.

Anthropic Claude Code

For most readers, the best place to use Claude Code with Builder MCP is the Claude Code VS Code extension.

Install Claude Code CLI. Then, verify the install:
```
claude --version
```

Add the Builder MCP Server from your project terminal:

claude mcp add --transport http flowgear https://your-environment-hostname.flowgear.net/mcp/builder

Start Claude from the same project folder:
```
claude
```
In Claude, run /mcp. Then, select Needs Auth or Authenticate for flowgear, and complete the browser sign-in flow.
Check that Claude Code can connect by sending a message such as list tools available in flowgear mcp server. You should see tools such as ListWorkflows and ListNodes.
By default, Claude Code will ask you to allow calls to each tool in Flowgear Builder MCP. There are typically a large number of tool calls, so if you would prefer not to be prompted before each tool is used, add an allowlist in .claude/settings.local.json:
```
{
  "permissions": {
    "allow": [
      "mcp__flowgear__*"
    ]
  }
}
```
- Optional (not recommended): run in bypass permissions mode so Claude does not prompt for approvals. Use this only in isolated sandboxed environments (e.g. dedicated dev containers or VMs):
  - VS Code Extension: enable Allow dangerously skip permissions, and then choose Bypass permissions from the mode indicator.
  - CLI: start with claude --dangerously-skip-permissions (or claude --permission-mode bypassPermissions).
  - Desktop App: enable dangerously skip permissions in Desktop settings, then choose Bypass permissions from the mode selector.
After setup, choose where you want to use Claude Code:
- Claude Code VS Code extension if you want the recommended editor-based option, with your files, terminal, and Builder MCP tools all in one place.
- Claude Code CLI if you prefer to work directly from the terminal, or if you are developing in a remote shell, container, or similar environment.
- Claude Code Desktop if you want a standalone desktop workspace. Anthropic's current docs say Claude Code Desktop and the CLI share Claude Code MCP configuration, but this is separate from the older Claude Desktop chat app MCP configuration.

Other Coding Agents

You can also use the Builder MCP Server with other coding agents, as long as the agent supports MCP tools.

Specifically, the agent must support:

Remote HTTP MCP servers.
OAuth 2.0 authentication flows.

Examples of coding agents that currently document these MCP capabilities:

Codex MCP
Codex IDE Extension
Codex CLI
Codex App
Codex Approvals and Security

Connect Claude Code to Tools via MCP
Claude Code Quickstart
Claude Code VS Code Extension
Claude Code Desktop
Claude Code Permissions
Claude Code Permission Modes