diff --git a/examples/flywheel_analyzer_afq.py b/examples/flywheel_analyzer_afq.py
index f451419..04da070 100644
--- a/examples/flywheel_analyzer_afq.py
+++ b/examples/flywheel_analyzer_afq.py
@@ -19,7 +19,8 @@ def afq_inputs(analyses, **kwargs):
     )
 
 if __name__ == '__main__':
-    fa.run([
-        fa.define_analysis('dtiinit', dtiinit_inputs),
-        fa.define_analysis('afq', afq_inputs),
-    ], project=fa.find_project(label='ENGAGE'))
+    with fa.installed_client():
+        fa.run([
+            fa.define_analysis('dtiinit', dtiinit_inputs),
+            fa.define_analysis('afq', afq_inputs),
+        ], project=fa.find_project(label='ENGAGE'))
diff --git a/examples/flywheel_analyzer_engage.py b/examples/flywheel_analyzer_engage.py
index efa7d42..c4f223a 100644
--- a/examples/flywheel_analyzer_engage.py
+++ b/examples/flywheel_analyzer_engage.py
@@ -1,4 +1,5 @@
 import scitran_client.flywheel_analyzer as fa
+from scitran_client import ScitranClient
 
 
 # XXX at least make this be just the first thing without ' 2'?
@@ -17,7 +18,7 @@
 
 def _find_file(container, glob):
     return (
-        container.find_file(glob) or
+        container.find_file(glob, default=None) or
         # HACK because flywheel does not currently support nested files
         # in output folders, we are flattening hierarchy by replacing
         # forward slashes with @@
@@ -80,16 +81,17 @@ def first_level_model_inputs(acquisition_label, analyses, acquisitions):
     ), dict(task_type=label_to_task_type[acquisition_label])
 
 if __name__ == '__main__':
-    fa.run([
-        define_analysis('reactivity-preprocessing', 'go-no-go 2', reactivity_inputs),
-        define_analysis('connectivity-preprocessing', 'go-no-go 2', connectivity_inputs),
-        define_analysis('first-level-models', 'go-no-go 2', first_level_model_inputs),
-
-        define_analysis('reactivity-preprocessing', 'conscious 2', reactivity_inputs),
-        define_analysis('connectivity-preprocessing', 'conscious 2', connectivity_inputs),
-        define_analysis('first-level-models', 'conscious 2', first_level_model_inputs),
-
-        define_analysis('reactivity-preprocessing', 'nonconscious 2', reactivity_inputs),
-        define_analysis('connectivity-preprocessing', 'nonconscious 2', connectivity_inputs),
-        define_analysis('first-level-models', 'nonconscious 2', first_level_model_inputs),
-    ], project=fa.find_project(label='ENGAGE'), session_limit=1)
+    with fa.installed_client(ScitranClient('https://flywheel-cni.scitran.stanford.edu')):
+        fa.run([
+            define_analysis('reactivity-preprocessing', 'go-no-go 2', reactivity_inputs),
+            define_analysis('connectivity-preprocessing', 'go-no-go 2', connectivity_inputs),
+            define_analysis('first-level-models', 'go-no-go 2', first_level_model_inputs),
+
+            define_analysis('reactivity-preprocessing', 'conscious 2', reactivity_inputs),
+            define_analysis('connectivity-preprocessing', 'conscious 2', connectivity_inputs),
+            define_analysis('first-level-models', 'conscious 2', first_level_model_inputs),
+
+            define_analysis('reactivity-preprocessing', 'nonconscious 2', reactivity_inputs),
+            define_analysis('connectivity-preprocessing', 'nonconscious 2', connectivity_inputs),
+            define_analysis('first-level-models', 'nonconscious 2', first_level_model_inputs),
+        ], project=fa.find_project(label='ENGAGE'), session_limit=1)
diff --git a/examples/flywheel_analyzer_showdes.py b/examples/flywheel_analyzer_showdes.py
index 5aefe21..4f38894 100644
--- a/examples/flywheel_analyzer_showdes.py
+++ b/examples/flywheel_analyzer_showdes.py
@@ -1,8 +1,12 @@
+from scitran_client import ScitranClient
 import scitran_client.flywheel_analyzer as fa
 
-D99 = fa.find(
-    fa.request('sessions/588bd1ac449f9800159305c2/acquisitions'),
-    label='atlas')
+client = ScitranClient('https://flywheel.scitran.stanford.edu')
+
+with fa.installed_client(client):
+    D99 = fa.find(
+        client.request('sessions/588bd1ac449f9800159305c2/acquisitions').json(),
+        label='atlas')
 
 
 def anatomical_warp_inputs(acquisitions, **kwargs):
@@ -14,6 +18,7 @@ def anatomical_warp_inputs(acquisitions, **kwargs):
     )
 
 if __name__ == '__main__':
-    fa.run([
-        fa.define_analysis('afni-brain-warp', anatomical_warp_inputs, label='anatomical warp'),
-    ], project=fa.find_project(label='showdes'), max_workers=2)
+    with fa.installed_client(client):
+        fa.run([
+            fa.define_analysis('afni-brain-warp', anatomical_warp_inputs, label='anatomical warp'),
+        ], project=fa.find_project(label='showdes'), max_workers=2)
diff --git a/scitran_client/flywheel_analyzer.py b/scitran_client/flywheel_analyzer.py
index 090fa7e..2d009e2 100644
--- a/scitran_client/flywheel_analyzer.py
+++ b/scitran_client/flywheel_analyzer.py
@@ -7,6 +7,7 @@
 from fnmatch import fnmatch
 from collections import namedtuple, Counter
 import math
+from contextlib import contextmanager
 
 
 def _sleep(seconds):
@@ -41,26 +42,46 @@ def define_analysis(gear_name, create_inputs, label=None):
 
 
 class FlywheelFileContainer(dict):
-    def find_file(self, pattern):
+    def find_file(self, pattern, **kwargs):
         '''Find a file in this container with a name that matches pattern.
 
         This will look for a file in this container that matches the supplied
         pattern. Matching uses the fnmatch python library, which does Unix
         filename pattern matching.
 
+        kwargs['default'] - like `next`, when a default is supplied, it will be
+        returned when there are no matches. When a default is not supplied, an
+        exception will be thrown.
+
         To find a specific file, you can simply match by name:
         > acquisition.find_file('anatomical.nii.gz')
 
         To find a file with an extension, you can use a Unix-style pattern:
         > stimulus_onsets.find_file('*.txt')
+
+        When looking for a file that might be missing, supply a default value:
+        > partial_set_of_files.find_file('*.txt', default=None)
         '''
-        # TODO make sure this throws for missing or multiple files.
-        is_analysis = 'job' in self and 'state' in self
+        has_default = 'default' in kwargs
+        is_analysis = 'job' in self
 
         # XXX if is_analysis then we should require the file to be an output??
-        f = next(
+        matches = [
             f for f in self['files']
-            if fnmatch(f['name'], pattern))
+            if fnmatch(f['name'], pattern)]
+
+        assert len(matches) <= 1, (
+            'Multiple matches found for pattern "{}" in container {}. Patterns should uniquely identify a file.'
+            .format(pattern, self['_id']))
+        if not matches:
+            if has_default:
+                return kwargs.get('default')
+            else:
+                raise Exception(
+                    'Could not find a match for "{}" in container {}.'
+                    .format(pattern, self['_id']))
+
+        f = matches[0]
 
         return dict(
             type='analysis' if is_analysis else 'acquisition',
@@ -104,8 +125,7 @@ class ShuttingDownException(Exception):
 
 def request(*args, **kwargs):
     # HACK client is a module variable for now. In the future, we should pass client around.
-    if 'client' not in state:
-        state['client'] = ScitranClient()
+    assert 'client' in state, 'client must be installed in state before using request. See `installed_client`.'
     response = state['client']._request(*args, **kwargs)
     return json.loads(response.text)
 
@@ -223,6 +243,24 @@ def done(f):
         raise
 
 
+@contextmanager
+def installed_client(client=None):
+    '''
+    This context manager handles the installation of a scitran client for use
+    in the flywheel analyzer. Most flywheel analyzer code depends on this being
+    set up.
+
+    > with installed_client():
+    >   print fa.find_project(label='ADHD study') # actually works!
+    '''
+    # BIG HACK
+    state['client'] = client or ScitranClient()
+    try:
+        yield state['client']
+    finally:
+        state['client'] = None
+
+
 def run(operations, project=None, max_workers=10, session_limit=None):
     """Run a sequence of FlywheelAnalysisOperations.
 
diff --git a/scitran_client/st_auth.py b/scitran_client/st_auth.py
index 37dff87..e6f75a1 100644
--- a/scitran_client/st_auth.py
+++ b/scitran_client/st_auth.py
@@ -25,17 +25,19 @@ def _prompt_for_valid_api_key(url):
     return api_key
 
 
-def create_token(instance_name, config_dir):
+def create_token(instance_name_or_host, config_dir):
     '''
     Get an API key for this instance, requesting a new one if no previous one exists.
 
     Args:
-        instance_name (str): The instance to generate a token for.
+        instance_name (str): The instance to generate a token for. Should only have one of `instance_name` or `host`.
+        host (str): The host we are are trying to generate a token for.
         config_dir (str): Path of directory where the tokens live.
 
     Returns:
         Python tuple: (token (str), client_url (str)): (The requested token, the base url for this client)
     '''
+
     if not os.path.exists(config_dir):
         os.mkdir(config_dir)
 
@@ -47,13 +49,21 @@ def create_token(instance_name, config_dir):
     with open(auth_path, 'r') as f:
         auth_config = json.load(f)
 
-    auth = auth_config.get(instance_name)
+    matches = [
+        a
+        for name, a in auth_config.iteritems()
+        if a['url'] == instance_name_or_host or name == instance_name_or_host
+    ]
+    assert len(matches) <= 1, \
+        'Too many matches for for {}. found: {}'.format(instance_name_or_host, matches)
+
+    auth = matches and matches[0]
 
     example = json.dumps(dict(api_key='<secret>', url='https://myflywheel.io'), indent=4)
     assert isinstance(auth, dict) and set(auth.keys()) == {'api_key', 'url'}, (
         'Missing or invalid entry in {0} for instance {1}. You can fix this issue by '
         'adding an entry for {1} or making it look more like this: {2}'
-        .format(auth_path, instance_name, example))
+        .format(auth_path, instance_name_or_host, example))
 
     # We just wipe out keys that are invalid.
     if auth['api_key'] and not _is_valid_token(auth['url'], auth['api_key']):
diff --git a/scitran_client/st_client.py b/scitran_client/st_client.py
index c4fa8ee..9e8e01e 100644
--- a/scitran_client/st_client.py
+++ b/scitran_client/st_client.py
@@ -55,8 +55,7 @@ class ScitranClient(object):
     '''Handles api calls to a certain instance.
 
     Attributes:
-        instance (str): instance name.
-        base_url (str): The base url of that instance, as returned by stAuth.create_token(instance, st_dir)
+        instance_name (str): instance name or host.
         token (str): Authentication token.
         st_dir (str): The path to the directory where token and authentication file are kept for this instance.
     '''
@@ -70,7 +69,7 @@ def __init__(self,
                  gear_out_dir=DEFAULT_OUTPUT_DIR):
 
         self.session = requests.Session()
-        self.instance = instance_name
+        self.instance_name_or_host = instance_name
         self.st_dir = st_dir
         self._authenticate()
         self.debug = debug
@@ -139,7 +138,7 @@ def _authenticate_request(self, request):
         return request
 
     def _authenticate(self):
-        self.token, self.base_url = st_auth.create_token(self.instance, self.st_dir)
+        self.token, self.base_url = st_auth.create_token(self.instance_name_or_host, self.st_dir)
         self.base_url = urlparse.urljoin(self.base_url, 'api/')
 
     def _request(self, *args, **kwargs):