Function resolveMcpEnv

sdk/src/agents/load-mcp-config.ts:44–72

(
  env: Record<string, string> | undefined,
  mcpServerName: string,
)

const processEnv = process[envKey] as NodeJS.ProcessEnv

function resolveMcpEnv(
  env: Record<string, string> | undefined,
  mcpServerName: string,
): Record<string, string> {
  if (!env) return {}

  const resolved: Record<string, string> = {}

  for (const [key, value] of Object.entries(env)) {
    if (value.startsWith('$')) {
      // $VAR_NAME reference - resolve from process.env
      const envVarName = value.slice(1) // Remove the leading $
      const envValue = processEnv[envVarName]

      if (envValue === undefined) {
        throw new Error(
          `Missing environment variable '${envVarName}' required by MCP server '${mcpServerName}' in mcp.json`,
        )
      }

      resolved[key] = envValue
    } else {
      // Plain string value - use as-is
      resolved[key] = value
    }
  }

  return resolved
}

/**
 * Resolves all MCP server env references in a config.