diff --git a/autoload/phpactor.vim b/autoload/phpactor.vim
index 44e2712df1..5344e3a143 100644
--- a/autoload/phpactor.vim
+++ b/autoload/phpactor.vim
@@ -327,7 +327,7 @@ endfunction
 " Utility functions
 """""""""""""""""""""""
 function! s:isOpenInCurrentWindow(filePath)
-  return expand('%:p') == a:filePath
+  return phpactor#_path() == a:filePath
 endfunction
 
 function! phpactor#_switchToBufferOrEdit(filePath)
@@ -353,7 +353,15 @@ function! phpactor#_source()
 endfunction
 
 function! phpactor#_path()
-    return expand('%:p')
+    let l:path = expand('%:p')
+
+    if filereadable(l:path) || stridx(l:path, '/') == 0
+      return l:path
+    endif
+
+    " todo if empty path
+    "
+    return printf('%s/%s', g:phpactorInitialCwd, l:path)
 endfunction
 
 function! s:getStartOffsetFromMark(mark, linewise)
@@ -435,14 +443,53 @@ endfunction
 " RPC -->-->-->-->-->--
 """""""""""""""""""""""
 
+function! s:searchDirectoryUpwardForRootPatterns(initialDirectory, workspaceRootPatterns, fallbackDirectory)
+  if index(g:phpactorGlobalRootPatterns, '/') < 0
+    call add(g:phpactorGlobalRootPatterns, '/')
+  endif
+
+  let l:directory = a:initialDirectory
+
+  while index(g:phpactorGlobalRootPatterns, l:directory) < 0
+    if s:directoryMatchesToPatterns(l:directory, a:workspaceRootPatterns)
+      return l:directory
+    endif
+
+    let l:directory = fnamemodify(l:directory, ':h')
+  endwhile
+
+  if index(g:phpactorGlobalRootPatterns, l:directory) >= 0
+    let l:directory = a:fallbackDirectory
+  endif
+
+  return l:directory
+endfunction
+
+function s:directoryMatchesToPatterns(directory, patterns) abort
+  for l:pattern in a:patterns
+    if (filereadable(a:directory .'/'. l:pattern))
+      return v:true
+    endif
+  endfor
+
+  return v:false
+endfunction
+
 function! phpactor#rpc(action, arguments)
     " Remove any existing output in the message window
     execute ':redraw'
 
     let request = { "action": a:action, "parameters": a:arguments }
 
-    let cmd = g:phpactorPhpBin . ' ' . g:phpactorbinpath . ' rpc --working-dir=' . g:phpactorInitialCwd
-    let result = system(cmd, json_encode(request))
+    let l:workspaceDir = s:searchDirectoryUpwardForRootPatterns(
+          \ fnamemodify(phpactor#_path(), ':h'),
+          \ g:phpactorProjectRootPatterns,
+          \ g:phpactorInitialCwd
+          \)
+
+    let l:cmd = g:phpactorPhpBin . ' ' . g:phpactorbinpath . ' rpc --working-dir=' . l:workspaceDir
+
+    let result = system(l:cmd, json_encode(request))
 
     if (v:shell_error == 0)
         try
diff --git a/composer.lock b/composer.lock
index 6c0270b205..4373c6ffa3 100644
--- a/composer.lock
+++ b/composer.lock
@@ -1916,12 +1916,12 @@
             "source": {
                 "type": "git",
                 "url": "https://github.com/phpactor/source-code-filesystem.git",
-                "reference": "72f53091d3692324ccde5d98cd9b666963884c9f"
+                "reference": "b1e11fdf14053becb37795f01bc5b9b48ea5871e"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/phpactor/source-code-filesystem/zipball/72f53091d3692324ccde5d98cd9b666963884c9f",
-                "reference": "72f53091d3692324ccde5d98cd9b666963884c9f",
+                "url": "https://api.github.com/repos/phpactor/source-code-filesystem/zipball/b1e11fdf14053becb37795f01bc5b9b48ea5871e",
+                "reference": "b1e11fdf14053becb37795f01bc5b9b48ea5871e",
                 "shasum": ""
             },
             "require": {
@@ -1955,7 +1955,7 @@
                 }
             ],
             "description": "Filesystem library for working with source code files",
-            "time": "2019-12-04T19:21:48+00:00"
+            "time": "2020-03-18T11:45:50+00:00"
         },
         {
             "name": "phpactor/source-code-filesystem-extension",
@@ -5789,5 +5789,6 @@
     "platform-dev": [],
     "platform-overrides": {
         "php": "7.2.5"
-    }
+    },
+    "plugin-api-version": "1.1.0"
 }
diff --git a/doc/phpactor.txt b/doc/phpactor.txt
index bd7a3ee279..d74c85fef7 100644
--- a/doc/phpactor.txt
+++ b/doc/phpactor.txt
@@ -48,6 +48,13 @@ is to use the VIM inputlist.
 When jumping to a file location: if the target file open in a window, switch
 to that window instead of switching buffers.  The default is false.
 
+                                               *g:phpactorProjectRootPatterns*
+The list of files that determine workspace root directory if contained within
+
+                                                *g:phpactorGlobalRootPatterns*
+The list of directories that should not be considered as workspace root
+directory (in addition to '/' which is always considered)
+
 ==============================================================================
 COMPLETION                                               *phpactor-completion*
 
diff --git a/ftplugin/php.vim b/ftplugin/php.vim
index 3e4e81ffaa..65cae72242 100644
--- a/ftplugin/php.vim
+++ b/ftplugin/php.vim
@@ -40,6 +40,16 @@ let g:phpactorInputListStrategy = get(g:, 'phpactorInputListStrategy', 'phpactor
 " to that window instead of switching buffers.  The default is false.
 let g:phpactorUseOpenWindows = get(g:, 'phpactorUseOpenWindows', v:false)
 
+""
+" The list of files that determine workspace root directory
+" if contained within
+let g:phpactorProjectRootPatterns = get(g:, 'phpactorProjectRootPatterns', ['composer.json', '.git', '.phpactor.json', '.phpactor.yml'])
+
+""
+" The list of directories that should not be considered as workspace root directory
+" (in addition to '/' which is always considered)
+let g:phpactorGlobalRootPatterns = get(g:, 'phpactorGlobalRootPatterns', ['/', '/home'])
+
 if g:phpactorOmniAutoClassImport == v:true
     autocmd CompleteDone *.php call phpactor#_completeImportClass(v:completed_item)
 endif