STDIO servers

STDIO servers are local processes that speak MCP over stdin/stdout.

UI fields

When Transport is set to "STDIO", the form shows:

• Command
• Args (comma-separated)
• Env (key:value per line, values may use {ENV_VAR})

Environment placeholders

In the UI, {ENV_VAR} placeholders are expanded from your environment at runtime. If you edit the config file directly, ${ENV_VAR} also works.

Command resolution

Broxy resolves the command to an absolute path before launching:

• If the command is missing, the server fails fast with a clear error.
• In the UI, command availability is checked after you finish editing the field.

Process behavior

• Each operation creates a short-lived connection to the server process.
• stderr output is treated as logs and does not affect the MCP protocol.

If you edit configuration files

{
  "name": "GitHub MCP",
  "transport": "stdio",
  "command": "npx",
  "args": ["@modelcontextprotocol/server-github"],
  "env": {
    "GITHUB_TOKEN": "${GITHUB_TOKEN}"
  }
}