diff --git a/lib/cli/doctor/index.js b/lib/cli/doctor/index.js
index 596dc5d6..2fe3017e 100644
--- a/lib/cli/doctor/index.js
+++ b/lib/cli/doctor/index.js
@@ -7,5 +7,180 @@ module.exports.builder = function(yargs) {
 }
 
 module.exports.handler = function() {
-  return require('../../util/doctor').run()
+  var cp = require('child_process')
+  var os = require('os')
+  var util = require('util')
+
+  var semver = require('semver')
+  var Promise = require('bluebird')
+  var zmq = require('zmq')
+
+  var pkg = require('../../../package')
+  var log = require('../../util/logger').createLogger('cli:doctor')
+
+  function CheckError() {
+    Error.captureStackTrace(this, this.constructor)
+    this.name = 'CheckError'
+    this.message = util.format.apply(util, arguments)
+  }
+
+  util.inherits(CheckError, Error)
+
+  function call(command, args, options) {
+    return new Promise(function(resolve, reject) {
+      var proc = cp.spawn(command, args, options)
+      var stdout = []
+
+      proc.stdout.on('readable', function() {
+        var chunk
+        while ((chunk = proc.stdout.read())) {
+          stdout.push(chunk)
+        }
+      })
+
+      proc.on('error', reject)
+
+      proc.on('exit', function(code, signal) {
+        if (signal) {
+          reject(new CheckError('Exited with signal %s', signal))
+        }
+        else if (code === 0) {
+          resolve(Buffer.concat(stdout).toString())
+        }
+        else {
+          reject(new CheckError('Exited with status %s', code))
+        }
+      })
+    })
+  }
+
+  function check(label, fn) {
+    return Promise.try(function() {
+      function Check() {
+      }
+
+      Check.prototype.call = function(command, args, options) {
+        return call(command, args, options).catch(function(err) {
+          if (err.code === 'ENOENT') {
+            throw new CheckError(
+              '%s is not installed (`%s` is missing)'
+            , label
+            , command
+            )
+          }
+
+          throw err
+        })
+      }
+
+      Check.prototype.extract = function(what, re) {
+        return function(input) {
+          return Promise.try(function() {
+            var match = re.exec(input)
+            if (!match) {
+              throw new CheckError(util.format('%s %s cannot be detected', label, what))
+            }
+            return match[1]
+          })
+        }
+      }
+
+      Check.prototype.version = function(wantedVersion) {
+        return function(currentVersion) {
+          return Promise.try(function() {
+            log.info('Using %s %s', label, currentVersion)
+            var sanitizedVersion = currentVersion.replace(/~.*/, '')
+            return semver.satisfies(sanitizedVersion, wantedVersion)
+          })
+          .then(function(satisfied) {
+            if (!satisfied) {
+              throw new CheckError(
+                '%s is currently %s but needs to be %s'
+              , label
+              , currentVersion
+              , wantedVersion
+              )
+            }
+          })
+        }
+      }
+
+      return fn(new Check())
+        .catch(CheckError, function(err) {
+          log.error(err.message)
+        })
+        .catch(function(err) {
+          log.error('Unexpected error checking %s: %s', label, err)
+        })
+    })
+  }
+
+  function checkOSArch() {
+    log.info('OS Arch: %s', os.arch())
+  }
+
+  function checkOSPlatform() {
+    log.info('OS Platform: %s', os.platform())
+    if (os.platform() === 'win32') {
+      log.warn('STF has never been tested on Windows. Contributions are welcome!')
+    }
+  }
+
+  function checkOSRelease() {
+    log.info('OS Platform: %s', os.release())
+  }
+
+  function checkNodeVersion() {
+    log.info('Using Node %s', process.versions.node)
+  }
+
+  function checkLocalRethinkDBVersion() {
+    return check('RethinkDB', function(checker) {
+      return checker.call('rethinkdb', ['--version'])
+        .then(checker.extract('version', /rethinkdb ([^\s]+)/))
+        .then(checker.version(pkg.externalDependencies.rethinkdb))
+    })
+  }
+
+  function checkGraphicsMagick() {
+    return check('GraphicsMagick', function(checker) {
+      return checker.call('gm', ['-version'])
+        .then(checker.extract('version', /GraphicsMagick ([^\s]+)/))
+        .then(checker.version(pkg.externalDependencies.gm))
+    })
+  }
+
+  function checkZeroMQ() {
+    return check('ZeroMQ', function(checker) {
+      return checker.version(pkg.externalDependencies.zeromq)(zmq.version)
+    })
+  }
+
+  function checkProtoBuf() {
+    return check('ProtoBuf', function(checker) {
+      return checker.call('protoc', ['--version'])
+        .then(checker.extract('version', /libprotoc ([^\s]+)/))
+        .then(checker.version(pkg.externalDependencies.protobuf))
+    })
+  }
+
+  function checkADB() {
+    return check('ADB', function(checker) {
+      return checker.call('adb', ['version'])
+        .then(checker.extract('version', /Android Debug Bridge version ([^\s]+)/))
+        .then(checker.version(pkg.externalDependencies.adb))
+    })
+  }
+
+  return Promise.all([
+    checkOSArch()
+  , checkOSPlatform()
+  , checkOSRelease()
+  , checkNodeVersion()
+  , checkLocalRethinkDBVersion()
+  , checkGraphicsMagick()
+  , checkZeroMQ()
+  , checkProtoBuf()
+  , checkADB()
+  ])
 }
diff --git a/lib/util/doctor.js b/lib/util/doctor.js
deleted file mode 100644
index 476ff25d..00000000
--- a/lib/util/doctor.js
+++ /dev/null
@@ -1,189 +0,0 @@
-var os = require('os')
-var semver = require('semver')
-var childProcess = require('child_process')
-var rethinkdbPkg = require('rethinkdb/package')
-var zmq = require('zmq')
-
-var pkg = require('../../package')
-var log = require('./logger').createLogger('util:doctor')
-
-var doctor = module.exports = Object.create(null)
-
-function unsupportedVersion(desc, ver, range, callback) {
-  if (!semver.satisfies(ver, range)) {
-    log.error(
-      'Current %s version is not supported, it has to be %s'
-      , desc
-      , range
-    )
-    if (callback) {
-      return callback()
-    }
-  }
-}
-
-function execHasErrors(error, stderr) {
-  if (error) {
-    if (error.code === 'ENOENT') {
-      log.warn('Executable was not found')
-    }
-    else {
-      log.error(error)
-    }
-    return true
-  }
-  if (stderr) {
-    log.error('There was an error with: %s', stderr)
-  }
-  return false
-}
-
-function execCommand(command, param, desc, match, callback) {
-  childProcess.execFile(command, [param],
-    function(error, stdout, stderr) {
-      if (!execHasErrors(error, stderr)) {
-        if (stdout) {
-          var result = stdout.replace(match, '$1')
-          if (result) {
-            log.info('%s %s', desc, result)
-            if (callback) {
-              return callback(result)
-            }
-          }
-          else {
-            log.error('There was an error with: %s', stdout)
-          }
-        }
-      }
-    }
-  )
-}
-
-doctor.checkOSArch = function() {
-  log.info('OS Arch: %s', os.arch())
-}
-
-doctor.checkOSPlatform = function() {
-  log.info('OS Platform: %s', os.platform())
-  if (os.platform() === 'win32') {
-    log.warn('STF has never been tested on Windows. Contributions are welcome!')
-  }
-}
-
-doctor.checkOSRelease = function() {
-  log.info('OS Platform: %s', os.release())
-}
-
-doctor.checkNodeVersion = function() {
-  log.info('Using Node %s', process.versions.node)
-  if (pkg.engineStrict) {
-    unsupportedVersion('Node', process.versions.node, pkg.engines.node)
-  }
-}
-
-doctor.checkRethinkDBClient = function() {
-  log.info('Using RethinkDB client %s', rethinkdbPkg.version)
-}
-
-doctor.checkLocalRethinkDBServer = function() {
-  execCommand(
-    'rethinkdb'
-    , '--version'
-    , 'Local RethinkDB server'
-    , /rethinkdb (.*?) \(.*\)\n?/gm
-    , function(ver) {
-      unsupportedVersion(
-        'Local RethinkDB server'
-        , ver
-        , pkg.externalDependencies.rethinkdb
-      )
-    })
-}
-
-doctor.checkGraphicsMagick = function() {
-  execCommand(
-    'gm'
-    , '-version'
-    , 'GraphicsMagick'
-    , /GraphicsMagick ((.|\n)*?) (.|\n)*/g
-    , function(ver) {
-      unsupportedVersion('GraphicsMagick', ver, pkg.externalDependencies.gm)
-    }
-  )
-}
-
-doctor.checkZeroMQ = function() {
-  log.info('Using ZeroMQ %s', zmq.version)
-
-  unsupportedVersion('ZeroMQ', zmq.version, pkg.externalDependencies.zeromq)
-}
-
-doctor.checkProtoBuf = function() {
-  execCommand(
-    'protoc'
-    , '--version'
-    , 'ProtoBuf'
-    , /^libprotoc (.*)\n$/g
-    , function(ver) {
-      unsupportedVersion(
-        'ProtoBuf'
-        , ver
-        , pkg.externalDependencies.protobuf
-      )
-    })
-}
-
-doctor.checkADB = function() {
-  execCommand(
-    'adb'
-    , 'version'
-    , 'Local ADB'
-    , /Android Debug Bridge version (\d+\.\d+\.\d+)(\n.*)?/g
-    , function(ver) {
-      unsupportedVersion('AD', ver, pkg.externalDependencies.adb)
-    }
-  )
-}
-
-doctor.run = function() {
-  // Check OS architecture
-  doctor.checkOSArch()
-
-  // Check OS platform
-  doctor.checkOSPlatform()
-
-  // Check OS release
-  doctor.checkOSRelease()
-
-  // Check node version
-  doctor.checkNodeVersion()
-
-  // Check rethinkdb client
-  doctor.checkRethinkDBClient()
-
-  // Check local rethinkdb server
-  doctor.checkLocalRethinkDBServer()
-
-  // Check graphicsmagick
-  doctor.checkGraphicsMagick()
-
-  // Check zeromq
-  doctor.checkZeroMQ()
-
-  // Check protobuf
-  doctor.checkProtoBuf()
-
-  // Check adb
-  doctor.checkADB()
-
-  // TODO:
-  // Check yasm
-  // Check pkg-config
-  // Check python2
-  // Exit on errors
-  // Run on stf local
-
-  // Only for stf local:
-  // Check if rethinkdb is running
-  // Check if adb server is running
-}