diff --git a/.github/ISSUE_TEMPLATE.md b/.github/ISSUE_TEMPLATE.md
index f1dc425c..c25697c6 100644
--- a/.github/ISSUE_TEMPLATE.md
+++ b/.github/ISSUE_TEMPLATE.md
@@ -4,6 +4,10 @@ Please drag-drop large logs as text file attachments.
 Feel free to write an issue in your preferred format, however if in doubt, use
 the following checklist as a guide for what to include.
 
+* Which version of Ansible are you running?
+* Is your version of Ansible patched in any way?
+* Are you running with any custom modules, or `module_utils` loaded?
+
 * Have you tried the latest master version from Git?
 * Do you have some idea of what the underlying problem may be?
   https://mitogen.rtfd.io/en/stable/ansible.html#common-problems has
diff --git a/MANIFEST.in b/MANIFEST.in
new file mode 100644
index 00000000..1aba38f6
--- /dev/null
+++ b/MANIFEST.in
@@ -0,0 +1 @@
+include LICENSE
diff --git a/ansible_mitogen/connection.py b/ansible_mitogen/connection.py
index c7e70c43..7bae8c25 100644
--- a/ansible_mitogen/connection.py
+++ b/ansible_mitogen/connection.py
@@ -547,7 +547,7 @@ class Connection(ansible.plugins.connection.ConnectionBase):
     def connected(self):
         return self.context is not None
 
-    def _spec_from_via(self, via_spec):
+    def _spec_from_via(self, proxied_inventory_name, via_spec):
         """
         Produce a dict connection specifiction given a string `via_spec`, of
         the form `[[become_method:]become_user@]inventory_hostname`.
@@ -555,17 +555,20 @@ class Connection(ansible.plugins.connection.ConnectionBase):
         become_user, _, inventory_name = via_spec.rpartition('@')
         become_method, _, become_user = become_user.rpartition(':')
 
-        via_vars = self.host_vars[inventory_name]
-        if isinstance(via_vars, jinja2.runtime.Undefined):
+        # must use __contains__ to avoid a TypeError for a missing host on
+        # Ansible 2.3.
+        if self.host_vars is None or inventory_name not in self.host_vars:
             raise ansible.errors.AnsibleConnectionFailure(
                 self.unknown_via_msg % (
                     via_spec,
-                    inventory_name,
+                    proxied_inventory_name,
                 )
             )
 
+        via_vars = self.host_vars[inventory_name]
         return ansible_mitogen.transport_config.MitogenViaSpec(
             inventory_name=inventory_name,
+            play_context=self._play_context,
             host_vars=dict(via_vars),  # TODO: make it lazy
             become_method=become_method or None,
             become_user=become_user or None,
@@ -615,7 +618,7 @@ class Connection(ansible.plugins.connection.ConnectionBase):
 
         if spec.mitogen_via():
             stack = self._stack_from_spec(
-                self._spec_from_via(spec.mitogen_via()),
+                self._spec_from_via(spec.inventory_name(), spec.mitogen_via()),
                 stack=stack,
                 seen_names=seen_names + (spec.inventory_name(),),
             )
diff --git a/ansible_mitogen/process.py b/ansible_mitogen/process.py
index 8137af9c..32f4a012 100644
--- a/ansible_mitogen/process.py
+++ b/ansible_mitogen/process.py
@@ -236,6 +236,41 @@ class MuxProcess(object):
         if secs:
             mitogen.debug.dump_to_logger(secs=secs)
 
+    def _setup_simplejson(self, responder):
+        """
+        We support serving simplejson for Python 2.4 targets on Ansible 2.3, at
+        least so the package's own CI Docker scripts can run without external
+        help, however newer versions of simplejson no longer support Python
+        2.4. Therefore override any installed/loaded version with a
+        2.4-compatible version we ship in the compat/ directory.
+        """
+        responder.whitelist_prefix('simplejson')
+
+        # issue #536: must be at end of sys.path, in case existing newer
+        # version is already loaded.
+        compat_path = os.path.join(os.path.dirname(__file__), 'compat')
+        sys.path.append(compat_path)
+
+        for fullname, is_pkg, suffix in (
+            (u'simplejson', True, '__init__.py'),
+            (u'simplejson.decoder', False, 'decoder.py'),
+            (u'simplejson.encoder', False, 'encoder.py'),
+            (u'simplejson.scanner', False, 'scanner.py'),
+        ):
+            path = os.path.join(compat_path, 'simplejson', suffix)
+            fp = open(path, 'rb')
+            try:
+                source = fp.read()
+            finally:
+                fp.close()
+
+            responder.add_source_override(
+                fullname=fullname,
+                path=path,
+                source=source,
+                is_pkg=is_pkg,
+            )
+
     def _setup_responder(self, responder):
         """
         Configure :class:`mitogen.master.ModuleResponder` to only permit
@@ -243,9 +278,7 @@ class MuxProcess(object):
         """
         responder.whitelist_prefix('ansible')
         responder.whitelist_prefix('ansible_mitogen')
-        responder.whitelist_prefix('simplejson')
-        simplejson_path = os.path.join(os.path.dirname(__file__), 'compat')
-        sys.path.insert(0, simplejson_path)
+        self._setup_simplejson(responder)
 
         # Ansible 2.3 is compatible with Python 2.4 targets, however
         # ansible/__init__.py is not. Instead, executor/module_common.py writes
diff --git a/ansible_mitogen/target.py b/ansible_mitogen/target.py
index 01877e34..58b715ce 100644
--- a/ansible_mitogen/target.py
+++ b/ansible_mitogen/target.py
@@ -377,6 +377,11 @@ def init_child(econtext, log_level, candidate_temp_dirs):
     LOG.setLevel(log_level)
     logging.getLogger('ansible_mitogen').setLevel(log_level)
 
+    # issue #536: if the json module is available, remove simplejson from the
+    # importer whitelist to avoid confusing certain Ansible modules.
+    if json.__name__ == 'json':
+        econtext.importer.whitelist.remove('simplejson')
+
     global _fork_parent
     if FORK_SUPPORTED:
         mitogen.parent.upgrade_router(econtext)
diff --git a/ansible_mitogen/transport_config.py b/ansible_mitogen/transport_config.py
index 3401b035..edc9ce1e 100644
--- a/ansible_mitogen/transport_config.py
+++ b/ansible_mitogen/transport_config.py
@@ -430,12 +430,33 @@ class MitogenViaSpec(Spec):
     having a configruation problem with connection delegation, the answer to
     your problem lies in the method implementations below!
     """
-    def __init__(self, inventory_name, host_vars,
-                 become_method, become_user):
+    def __init__(self, inventory_name, host_vars, become_method, become_user,
+                 play_context):
+        """
+        :param str inventory_name:
+            The inventory name of the intermediary machine, i.e. not the target
+            machine.
+        :param dict host_vars:
+            The HostVars magic dictionary provided by Ansible in task_vars.
+        :param str become_method:
+            If the mitogen_via= spec included a become method, the method it
+            specifies.
+        :param str become_user:
+            If the mitogen_via= spec included a become user, the user it
+            specifies.
+        :param PlayContext play_context:
+            For some global values **only**, the PlayContext used to describe
+            the real target machine. Values from this object are **strictly
+            restricted** to values that are Ansible-global, e.g. the passwords
+            specified interactively.
+        """
         self._inventory_name = inventory_name
         self._host_vars = host_vars
         self._become_method = become_method
         self._become_user = become_user
+        # Dangerous! You may find a variable you want in this object, but it's
+        # almost certainly for the wrong machine!
+        self._dangerous_play_context = play_context
 
     def transport(self):
         return (
@@ -447,15 +468,17 @@ class MitogenViaSpec(Spec):
         return self._inventory_name
 
     def remote_addr(self):
+        # play_context.py::MAGIC_VARIABLE_MAPPING
         return (
+            self._host_vars.get('ansible_ssh_host') or
             self._host_vars.get('ansible_host') or
             self._inventory_name
         )
 
     def remote_user(self):
         return (
-            self._host_vars.get('ansible_user') or
             self._host_vars.get('ansible_ssh_user') or
+            self._host_vars.get('ansible_user') or
             C.DEFAULT_REMOTE_USER
         )
 
@@ -463,7 +486,11 @@ class MitogenViaSpec(Spec):
         return bool(self._become_user)
 
     def become_method(self):
-        return self._become_method or C.DEFAULT_BECOME_METHOD
+        return (
+            self._become_method or
+            self._host_vars.get('ansible_become_method') or
+            C.DEFAULT_BECOME_METHOD
+        )
 
     def become_user(self):
         return self._become_user
@@ -477,7 +504,6 @@ class MitogenViaSpec(Spec):
 
     def password(self):
         return optional_secret(
-            # TODO: Might have to come from PlayContext.
             self._host_vars.get('ansible_ssh_pass') or
             self._host_vars.get('ansible_password')
         )
@@ -495,7 +521,6 @@ class MitogenViaSpec(Spec):
         # interpreter is specified.
         return parse_python_path(s or '/usr/bin/python')
 
-
     def private_key_file(self):
         # TODO: must come from PlayContext too.
         return (
diff --git a/docs/_static/style.css b/docs/_static/style.css
index ec25901f..98dd4bac 100644
--- a/docs/_static/style.css
+++ b/docs/_static/style.css
@@ -1,4 +1,66 @@
 
+body {
+    font-size: 100%;
+}
+
+.sphinxsidebar {
+    font-size: 80% !important;
+}
+
+.sphinxsidebar h3 {
+    font-size: 130% !important;
+}
+
+img + p,
+h1 + p,
+h2 + p,
+h3 + p,
+h4 + p,
+h5 + p
+{
+    margin-top: 0;
+}
+
+.section > h3:first-child {
+    margin-top: 15px !important;
+}
+
+.body h1 { font-size: 200% !important; }
+.body h2 { font-size: 165% !important; }
+.body h3 { font-size: 125% !important; }
+.body h4 { font-size: 110% !important; font-weight: bold; }
+.body h5 { font-size: 100% !important; font-weight: bold; }
+
+.body h1,
+.body h2,
+.body h3,
+.body h4,
+.body h5 {
+    margin-top: 30px !important;
+    color: #7f0000;
+}
+
+.body h1 {
+    margin-top: 0 !important;
+}
+
+body,
+.sphinxsidebar,
+.sphinxsidebar h1,
+.sphinxsidebar h2,
+.sphinxsidebar h3,
+.sphinxsidebar h4,
+.sphinxsidebar h5,
+.body h1,
+.body h2,
+.body h3,
+.body h4,
+.body h5 {
+    /*font-family: sans-serif !important;*/
+    font-family: -apple-system,BlinkMacSystemFont,Segoe UI,Helvetica,Arial,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol !important;
+}
+
+
 .document {
     width: 1000px !important;
 }
@@ -38,10 +100,10 @@ div.body p, div.body dd, div.body li, div.body blockquote {
     width: 150px;
 }
 
-.mitogen-right-200 {
+.mitogen-right-180 {
     float: right;
     padding-left: 8px;
-    width: 200px;
+    width: 180px;
 }
 
 .mitogen-right-225 {
diff --git a/docs/_templates/github.html b/docs/_templates/github.html
index 12533b52..bb2b5ee5 100644
--- a/docs/_templates/github.html
+++ b/docs/_templates/github.html
@@ -1,8 +1,4 @@
 <p>
 <br>
-<a class="github-button" href="https://github.com/dw/mitogen" data-size="large" data-show-count="true" aria-label="Star dw/mitogen on GitHub">Star</a>
-</p>
-
-<p>
-<a href="https://github.com/dw/mitogen/">GitHub Repository</a>
+<a class="github-button" href="https://github.com/dw/mitogen/" data-size="large" data-show-count="true" aria-label="Star dw/mitogen on GitHub">Star</a>
 </p>
diff --git a/docs/ansible.rst b/docs/ansible.rst
index 17354755..f7788011 100644
--- a/docs/ansible.rst
+++ b/docs/ansible.rst
@@ -3,7 +3,7 @@ Mitogen for Ansible
 ===================
 
 .. image:: images/ansible/ansible_mitogen.svg
-    :class: mitogen-right-200 mitogen-logo-wrap
+    :class: mitogen-right-180 mitogen-logo-wrap
 
 An extension to `Ansible`_ is included that implements connections over
 Mitogen, replacing embedded shell invocations with pure-Python equivalents
@@ -246,6 +246,11 @@ container.
       as duplicate connections between hops, due to not perfectly replicating
       the configuration Ansible would normally use for the intermediary.
 
+    * Intermediary machines cannot use login and become passwords that were
+      supplied to Ansible interactively. If an intermediary requires a
+      password, it must be supplied via ``ansible_ssh_pass``,
+      ``ansible_password``, or ``ansible_become_pass`` inventory variables.
+
     * Automatic tunnelling of SSH-dependent actions, such as the
       ``synchronize`` module, is not yet supported. This will be added in the
       0.3 series.
diff --git a/docs/changelog.rst b/docs/changelog.rst
index 635115e7..b037ace1 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -10,7 +10,7 @@ Release Notes
     <style>
         div#release-notes h2 {
             border-bottom: 1px dotted #c0c0c0;
-            margin-top: 40px;
+            margin-top: 50px !important;
         }
     </style>
 
@@ -128,16 +128,40 @@ Core Library
 v0.2.5 (2019-02-1?)
 -------------------
 
+Fixes
+~~~~~
+
 * `#511 <https://github.com/dw/mitogen/issues/511>`_,
   `#536 <https://github.com/dw/mitogen/issues/536>`_: changes in 0.2.4 to
   repair ``delegate_to`` handling broke default ``ansible_python_interpreter``
   handling. Test coverage was added.
 
+* `#536 <https://github.com/dw/mitogen/issues/536>`_: changes in 0.2.4 to
+  support Python 2.4 interacted poorly with modules that imported
+  ``simplejson`` from a controller that also loaded an incompatible newer
+  version of ``simplejson``.
+
+* `#538 <https://github.com/dw/mitogen/issues/538>`_: the Mitogen source
+  distribution includes a requisite ``LICENSE`` file.
+
+* `748f5f67 <https://github.com/dw/mitogen/commit/748f5f67>`_: the
+  ``ansible_ssh_host`` variable is respected when ``mitogen_via=`` is active.
+
+* `21ad299d <https://github.com/dw/mitogen/commit/21ad299d>`_: the
+  precedence of ``ansible_ssh_user`` and ``ansible_user`` variables were
+  corrected when ``mitogen_via=`` is active.
+
+* `8ae6ca1d <https://github.com/dw/mitogen/commit/8ae6ca1d>`_: the
+  ``ansible_become_method`` variable is respected when ``mitogen_via=`` is
+  active.
+
+
 Thanks!
 ~~~~~~~
 
 Mitogen would not be possible without the support of users. A huge thanks for
 bug reports, testing, features and fixes in this release contributed by
+`Carl George <https://github.com/carlwgeorge>`_,
 `Guy Knights <https://github.com/knightsg>`_, and
 `Josh Smift <https://github.com/jbscare>`_,
 
diff --git a/docs/conf.py b/docs/conf.py
index abb6e97e..3708a943 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -17,6 +17,10 @@ html_theme = 'alabaster'
 html_theme_options = {
     'font_family': "Georgia, serif",
     'head_font_family': "Georgia, serif",
+    'fixed_sidebar': True,
+    'show_powered_by': False,
+    'pink_2': 'fffafaf',
+    'pink_1': '#fff0f0',
 }
 htmlhelp_basename = 'mitogendoc'
 intersphinx_mapping = {'python': ('https://docs.python.org/3', None)}
diff --git a/docs/index.rst b/docs/index.rst
index 066d6716..6b5deb71 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -11,7 +11,7 @@ Mitogen
     </style>
 
 .. image:: images/mitogen.svg
-    :class: mitogen-right-200 mitogen-logo-wrap
+    :class: mitogen-right-180 mitogen-logo-wrap
 
 Mitogen is a Python library for writing distributed self-replicating programs.
 
diff --git a/mitogen/core.py b/mitogen/core.py
index a48e13ed..9f329d88 100644
--- a/mitogen/core.py
+++ b/mitogen/core.py
@@ -1125,6 +1125,11 @@ class Importer(object):
         self.whitelist = list(whitelist) or ['']
         self.blacklist = list(blacklist) + self.ALWAYS_BLACKLIST
 
+        # Preserve copies of the original server-supplied whitelist/blacklist
+        # for later use by children.
+        self.master_whitelist = self.whitelist[:]
+        self.master_blacklist = self.blacklist[:]
+
         # Presence of an entry in this map indicates in-flight GET_MODULE.
         self._callbacks = {}
         self._cache = {}
diff --git a/mitogen/master.py b/mitogen/master.py
index 257fb81b..18323844 100644
--- a/mitogen/master.py
+++ b/mitogen/master.py
@@ -485,8 +485,10 @@ class ModuleFinder(object):
         return path, source, is_pkg
 
     def _get_module_via_sys_modules(self, fullname):
-        """Attempt to fetch source code via sys.modules. This is specifically
-        to support __main__, but it may catch a few more cases."""
+        """
+        Attempt to fetch source code via sys.modules. This is specifically to
+        support __main__, but it may catch a few more cases.
+        """
         module = sys.modules.get(fullname)
         LOG.debug('_get_module_via_sys_modules(%r) -> %r', fullname, module)
         if not isinstance(module, types.ModuleType):
@@ -883,10 +885,13 @@ class ModuleResponder(object):
         if msg.is_dead:
             return
 
-        LOG.debug('%r._on_get_module(%r)', self, msg.data)
-        self.get_module_count += 1
         stream = self._router.stream_by_id(msg.src_id)
+        if stream is None:
+            return
+
         fullname = msg.data.decode()
+        LOG.debug('%s requested module %s', stream.name, fullname)
+        self.get_module_count += 1
         if fullname in stream.sent_modules:
             LOG.warning('_on_get_module(): dup request for %r from %r',
                         fullname, stream)
diff --git a/mitogen/parent.py b/mitogen/parent.py
index 91a4e5eb..814d20e3 100644
--- a/mitogen/parent.py
+++ b/mitogen/parent.py
@@ -2054,12 +2054,12 @@ class Router(mitogen.core.Router):
     def get_module_blacklist(self):
         if mitogen.context_id == 0:
             return self.responder.blacklist
-        return self.importer.blacklist
+        return self.importer.master_blacklist
 
     def get_module_whitelist(self):
         if mitogen.context_id == 0:
             return self.responder.whitelist
-        return self.importer.whitelist
+        return self.importer.master_whitelist
 
     def allocate_id(self):
         return self.id_allocator.allocate()
diff --git a/tests/ansible/ansible.cfg b/tests/ansible/ansible.cfg
index a968f84a..bec749f7 100644
--- a/tests/ansible/ansible.cfg
+++ b/tests/ansible/ansible.cfg
@@ -1,5 +1,5 @@
 [defaults]
-inventory = hosts,lib/inventory
+inventory = hosts
 gathering = explicit
 strategy_plugins = ../../ansible_mitogen/plugins/strategy
 action_plugins = lib/action
diff --git a/tests/ansible/hosts/transport_config.hosts b/tests/ansible/hosts/transport_config.hosts
index d9685811..c98d4f41 100644
--- a/tests/ansible/hosts/transport_config.hosts
+++ b/tests/ansible/hosts/transport_config.hosts
@@ -1,10 +1,33 @@
 # integration/transport_config
 # Hosts with twiddled configs that need to be checked somehow.
 
+
+# tansport()
+tc-transport-unset
+tc-transport-local ansible_connection=local
+
+# python_path()
 tc-python-path-unset
 tc-python-path-hostvar  ansible_python_interpreter=/hostvar/path/to/python
-
-# local connections get virtualenv python path
 tc-python-path-local-unset ansible_connection=local
 tc-python-path-local-explicit ansible_connection=local ansible_python_interpreter=/a/b/c
 
+# remote_addr()
+tc-remote-addr-unset  # defaults to inventory_hostname
+tc-remote-addr-explicit-ssh ansible_ssh_host=ansi.ssh.host
+tc-remote-addr-explicit-host ansible_host=ansi.host
+tc-remote-addr-explicit-both ansible_ssh_host=a.b.c ansible_host=b.c.d
+
+# password()
+tc-password-unset
+tc-password-explicit-ssh  ansible_ssh_pass=ansi-ssh-pass
+tc-password-explicit-user ansible_password=ansi-pass
+tc-password-explicit-both ansible_password=a.b.c ansible_ssh_pass=c.b.a
+
+# become()
+tc-become-unset
+tc-become-set
+
+# become_method()
+tc-become-method-unset
+tc-become-method-su ansible_become_method=su
diff --git a/tests/ansible/integration/_mitogen_only.yml b/tests/ansible/integration/_mitogen_only.yml
new file mode 100644
index 00000000..85ef378e
--- /dev/null
+++ b/tests/ansible/integration/_mitogen_only.yml
@@ -0,0 +1,4 @@
+# Include me for plays that can't run on vanilla.
+#
+- meta: end_play
+  when: not is_mitogen
diff --git a/tests/ansible/integration/transport_config/all.yml b/tests/ansible/integration/transport_config/all.yml
index 704760d1..908f6735 100644
--- a/tests/ansible/integration/transport_config/all.yml
+++ b/tests/ansible/integration/transport_config/all.yml
@@ -1,2 +1,7 @@
-
+- include: become.yml
+- include: become_method.yml
+- include: password.yml
 - include: python_path.yml
+- include: remote_addr.yml
+- include: remote_user.yml
+- include: transport.yml
diff --git a/tests/ansible/integration/transport_config/become.yml b/tests/ansible/integration/transport_config/become.yml
new file mode 100644
index 00000000..baa2085e
--- /dev/null
+++ b/tests/ansible/integration/transport_config/become.yml
@@ -0,0 +1,68 @@
+# Each case is followed by mitogen_via= case to test hostvars method.
+
+
+# No become set.
+- name: integration/transport_config/become.yml
+  hosts: tc-become-unset
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert:
+      that:
+      - out.result|length == 1
+      - out.result[0].method == "ssh"
+      - out.result[0].kwargs.username == "ansible-cfg-remote-user"
+
+- hosts: tc-become-unset
+  vars: {mitogen_via: becomeuser@tc-become-set}
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert:
+      that:
+      - out.result|length == 3
+      - out.result[0].method == "ssh"
+      - out.result[0].kwargs.username == "ansible-cfg-remote-user"
+
+      - out.result[1].method == "sudo"
+      - out.result[1].kwargs.username == "becomeuser"
+
+      - out.result[2].method == "ssh"
+      - out.result[2].kwargs.hostname == "tc-become-unset"
+
+
+# Become set.
+- name: integration/transport_config/become.yml
+  hosts: tc-become-set
+  become: true
+  become_user: becomeuser
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert:
+      that:
+      - out.result|length == 2
+      - out.result[0].method == "ssh"
+      - out.result[0].kwargs.username == "ansible-cfg-remote-user"
+      - out.result[1].method == "sudo"
+      - out.result[1].kwargs.username == "becomeuser"
+
+- hosts: tc-become-set
+  vars: {mitogen_via: tc-become-unset}
+  become: true
+  become_user: becomeuser
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert:
+      that:
+      - out.result|length == 3
+      - out.result[0].method == "ssh"
+      - out.result[0].kwargs.hostname == "tc-become-unset"
+      - out.result[0].kwargs.username == "ansible-cfg-remote-user"
+
+      - out.result[1].method == "ssh"
+      - out.result[1].kwargs.hostname == "tc-become-set"
+
+      - out.result[2].method == "sudo"
+      - out.result[2].kwargs.username == "becomeuser"
diff --git a/tests/ansible/integration/transport_config/become_method.yml b/tests/ansible/integration/transport_config/become_method.yml
new file mode 100644
index 00000000..5129e5b8
--- /dev/null
+++ b/tests/ansible/integration/transport_config/become_method.yml
@@ -0,0 +1,83 @@
+# Each case is followed by mitogen_via= case to test hostvars method.
+
+
+# No become-method set.
+- name: integration/transport_config/become-method.yml
+  hosts: tc-become-method-unset
+  become: true
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert:
+      that:
+      - out.result|length == 2
+      - out.result[0].method == "ssh"
+      - out.result[1].method == "sudo"
+
+- hosts: tc-become-method-unset
+  vars: {mitogen_via: becomeuser@tc-become-method-su}
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert:
+      that:
+      - out.result|length == 3
+      - out.result[0].method == "ssh"
+      - out.result[1].method == "su"
+      - out.result[1].kwargs.username == "becomeuser"
+      - out.result[2].method == "ssh"
+      - out.result[2].kwargs.hostname == "tc-become-method-unset"
+
+
+# ansible_become_method=su
+- hosts: tc-become-method-su
+  become: true
+  become_user: becomeuser
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert:
+      that:
+      - out.result|length == 2
+      - out.result[0].method == "ssh"
+      - out.result[1].method == "su"
+      - out.result[1].kwargs.username == "becomeuser"
+
+- hosts: tc-become-method-su
+  vars: {mitogen_via: tc-become-method-unset}
+  become: true
+  become_user: becomeuser
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert:
+      that:
+      - out.result|length == 3
+      - out.result[0].method == "ssh"
+      - out.result[0].kwargs.hostname == "tc-become-method-unset"
+
+      - out.result[1].method == "ssh"
+      - out.result[1].kwargs.hostname == "tc-become-method-su"
+
+      - out.result[2].method == "su"
+      - out.result[2].kwargs.username == "becomeuser"
+
+
+
+# mitogen_via used to specify explicit become method
+- hosts: tc-become-method-unset
+  vars: {mitogen_via: "doas:doasuser@tc-become-method-su"}
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert:
+      that:
+      - out.result|length == 3
+      - out.result[0].method == "ssh"
+      - out.result[0].kwargs.hostname == "tc-become-method-su"
+
+      - out.result[1].method == "doas"
+      - out.result[1].kwargs.username == "doasuser"
+
+      - out.result[2].method == "ssh"
+      - out.result[2].kwargs.hostname == "tc-become-method-unset"
diff --git a/tests/ansible/integration/transport_config/password.yml b/tests/ansible/integration/transport_config/password.yml
new file mode 100644
index 00000000..ac236d66
--- /dev/null
+++ b/tests/ansible/integration/transport_config/password.yml
@@ -0,0 +1,94 @@
+# Each case is followed by mitogen_via= case to test hostvars method.
+
+
+# When no ansible_ssh_pass/ansible_password= is set, password comes via
+# interactive input.
+- name: integration/transport_config/password.yml
+  hosts: tc-password-unset
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.password
+      right: ""  # actually null, but assert_equal limitation
+
+- hosts: tc-password-unset
+  vars: {mitogen_via: tc-password-explicit-ssh}
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.password
+      right: "ansi-ssh-pass"
+  - assert_equal:
+      left: out.result[1].kwargs.password
+      right: ""
+
+
+# ansible_ssh_user=
+
+- hosts: tc-password-explicit-ssh
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.password
+      right: "ansi-ssh-pass"
+
+- hosts: tc-password-explicit-ssh
+  vars: {mitogen_via: tc-password-unset}
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.password
+      right: ""
+  - assert_equal:
+      left: out.result[1].kwargs.password
+      right: "ansi-ssh-pass"
+
+
+# ansible_user=
+
+- hosts: tc-password-explicit-pass
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.password
+      right: "ansi-pass"
+
+- hosts: tc-password-explicit-pass
+  vars: {mitogen_via: tc-password-unset}
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.password
+      right: ""
+  - assert_equal:
+      left: out.result[1].kwargs.password
+      right: "ansi-pass"
+
+
+# both; ansible_ssh_user= takes precedence according to play_context.py.
+
+- hosts: tc-password-explicit-both
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.password
+      right: "c.b.a"
+
+- hosts: tc-password-explicit-both
+  vars: {mitogen_via: tc-password-unset}
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.password
+      right: ""
+  - assert_equal:
+      left: out.result[1].kwargs.password
+      right: "c.b.a"
diff --git a/tests/ansible/integration/transport_config/python_path.yml b/tests/ansible/integration/transport_config/python_path.yml
index d0c16788..c5359e93 100644
--- a/tests/ansible/integration/transport_config/python_path.yml
+++ b/tests/ansible/integration/transport_config/python_path.yml
@@ -1,4 +1,5 @@
 # related: issue #511, #536
+# Each case is followed by mitogen_via= case to test hostvars method.
 
 
 # When no ansible_python_interpreter is set, executor/module_common.py chooses
@@ -6,57 +7,108 @@
 - name: integration/transport_config/python_path.yml
   hosts: tc-python-path-unset
   tasks:
-  - meta: end_play
-    when: not is_mitogen
-  - mitogen_get_stack:
-    register: out
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
   - assert_equal:
       left: out.result[0].kwargs.python_path
       right: ["/usr/bin/python"]
 
+- hosts: tc-python-path-hostvar
+  vars: {mitogen_via: tc-python-path-unset}
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.python_path
+      right: ["/usr/bin/python"]
+  - assert_equal:
+      left: out.result[1].kwargs.python_path
+      right: ["/hostvar/path/to/python"]
+
 
 # Non-localhost with explicit ansible_python_interpreter
 - hosts: tc-python-path-hostvar
   tasks:
-  - meta: end_play
-    when: not is_mitogen
-  - mitogen_get_stack:
-    register: out
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
   - assert_equal:
       left: out.result[0].kwargs.python_path
       right: [/hostvar/path/to/python]
 
+- hosts: tc-python-path-unset
+  vars: {mitogen_via: tc-python-path-hostvar}
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.python_path
+      right: ["/hostvar/path/to/python"]
+  - assert_equal:
+      left: out.result[1].kwargs.python_path
+      right: ["/usr/bin/python"]
+
 
 # Implicit localhost gets ansible_python_interpreter=virtualenv interpreter
 - hosts: localhost
   tasks:
-  - meta: end_play
-    when: not is_mitogen
-  - mitogen_get_stack:
-    register: out
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.python_path
+      right: ["{{ansible_playbook_python}}"]
+
+- hosts: tc-python-path-unset
+  vars: {mitogen_via: localhost}
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
   - assert_equal:
       left: out.result[0].kwargs.python_path
       right: ["{{ansible_playbook_python}}"]
+  - assert_equal:
+      left: out.result[1].kwargs.python_path
+      right: ["/usr/bin/python"]
 
 
 # explicit local connections get the same treatment as everything else.
 - hosts: tc-python-path-local-unset
   tasks:
-  - meta: end_play
-    when: not is_mitogen
-  - mitogen_get_stack:
-    register: out
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
   - assert_equal:
       left: out.result[0].kwargs.python_path
       right: ["/usr/bin/python"]
 
+- hosts: localhost
+  vars: {mitogen_via: tc-python-path-local-unset}
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.python_path
+      right: ["/usr/bin/python"]
+  - assert_equal:
+      left: out.result[1].kwargs.python_path
+      right: ["{{ansible_playbook_python}}"]
+
 
+# explicit local connection with explicit interpreter
 - hosts: tc-python-path-local-explicit
   tasks:
-  - meta: end_play
-    when: not is_mitogen
-  - mitogen_get_stack:
-    register: out
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
   - assert_equal:
       left: out.result[0].kwargs.python_path
       right: ["/a/b/c"]
+
+- hosts: localhost
+  vars: {mitogen_via: tc-python-path-local-explicit}
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.python_path
+      right: ["/a/b/c"]
+  - assert_equal:
+      left: out.result[1].kwargs.python_path
+      right: ["{{ansible_playbook_python}}"]
diff --git a/tests/ansible/integration/transport_config/remote_addr.yml b/tests/ansible/integration/transport_config/remote_addr.yml
new file mode 100644
index 00000000..b9887202
--- /dev/null
+++ b/tests/ansible/integration/transport_config/remote_addr.yml
@@ -0,0 +1,95 @@
+
+# Each case is followed by mitogen_via= case to test hostvars method.
+
+
+# When no ansible_host/ansible_ssh_host= is set, hostname is same as inventory
+# name.
+- name: integration/transport_config/remote_addr.yml
+  hosts: tc-remote-addr-unset
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.hostname
+      right: "tc-remote-addr-unset"
+
+- hosts: tc-remote-addr-unset
+  vars: {mitogen_via: tc-remote-addr-explicit-ssh}
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.hostname
+      right: "ansi.ssh.host"
+  - assert_equal:
+      left: out.result[1].kwargs.hostname
+      right: "tc-remote-addr-unset"
+
+
+# ansible_ssh_host=
+
+- hosts: tc-remote-addr-explicit-ssh
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.hostname
+      right: "ansi.ssh.host"
+
+- hosts: tc-remote-addr-explicit-ssh
+  vars: {mitogen_via: tc-remote-addr-unset}
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.hostname
+      right: "tc-remote-addr-unset"
+  - assert_equal:
+      left: out.result[1].kwargs.hostname
+      right: "ansi.ssh.host"
+
+
+# ansible_host=
+
+- hosts: tc-remote-addr-explicit-host
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.hostname
+      right: "ansi.host"
+
+- hosts: tc-remote-addr-explicit-host
+  vars: {mitogen_via: tc-remote-addr-unset}
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.hostname
+      right: "tc-remote-addr-unset"
+  - assert_equal:
+      left: out.result[1].kwargs.hostname
+      right: "ansi.host"
+
+
+# both; ansible_ssh_host= takes precedence according to play_context.py.
+
+- hosts: tc-remote-addr-explicit-both
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.hostname
+      right: "a.b.c"
+
+- hosts: tc-remote-addr-explicit-both
+  vars: {mitogen_via: tc-remote-addr-unset}
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.hostname
+      right: "tc-remote-addr-unset"
+  - assert_equal:
+      left: out.result[1].kwargs.hostname
+      right: "a.b.c"
diff --git a/tests/ansible/integration/transport_config/remote_user.yml b/tests/ansible/integration/transport_config/remote_user.yml
new file mode 100644
index 00000000..b873fcbe
--- /dev/null
+++ b/tests/ansible/integration/transport_config/remote_user.yml
@@ -0,0 +1,96 @@
+
+# Each case is followed by mitogen_via= case to test hostvars method.
+
+
+# When no ansible_user/ansible_ssh_user= is set, username is
+# C.DEFAULT_REMOTE_USER.
+- name: integration/transport_config/remote_user.yml
+  hosts: tc-remote-user-unset
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.username
+      # We set DEFAULT_REMOTE_USER in our ansible.cfg
+      right: "ansible-cfg-remote-user"
+
+- hosts: tc-remote-user-unset
+  vars: {mitogen_via: tc-remote-user-explicit-ssh}
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.username
+      right: "ansi-ssh-user"
+  - assert_equal:
+      left: out.result[1].kwargs.username
+      right: "ansible-cfg-remote-user"
+
+
+# ansible_ssh_user=
+
+- hosts: tc-remote-user-explicit-ssh
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.username
+      right: "ansi-ssh-user"
+
+- hosts: tc-remote-user-explicit-ssh
+  vars: {mitogen_via: tc-remote-user-unset}
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.username
+      right: "ansible-cfg-remote-user"
+  - assert_equal:
+      left: out.result[1].kwargs.username
+      right: "ansi-ssh-user"
+
+
+# ansible_user=
+
+- hosts: tc-remote-user-explicit-user
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.username
+      right: "ansi-user"
+
+- hosts: tc-remote-user-explicit-host
+  vars: {mitogen_via: tc-remote-user-unset}
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.username
+      right: "ansible-cfg-remote-user"
+  - assert_equal:
+      left: out.result[1].kwargs.username
+      right: "ansi-user"
+
+
+# both; ansible_ssh_user= takes precedence according to play_context.py.
+
+- hosts: tc-remote-user-explicit-both
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.username
+      right: "c.b.a"
+
+- hosts: tc-remote-user-explicit-both
+  vars: {mitogen_via: tc-remote-user-unset}
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].kwargs.username
+      right: "ansible-cfg-remote-user"
+  - assert_equal:
+      left: out.result[1].kwargs.username
+      right: "c.b.a"
diff --git a/tests/ansible/integration/transport_config/transport.yml b/tests/ansible/integration/transport_config/transport.yml
new file mode 100644
index 00000000..efedc8d4
--- /dev/null
+++ b/tests/ansible/integration/transport_config/transport.yml
@@ -0,0 +1,48 @@
+# Each case is followed by mitogen_via= case to test hostvars method.
+
+
+# When no ansible_connection= is set, transport comes via ansible.cfg ("smart"
+# is parsed away to either paramiko or ssh).
+- name: integration/transport_config/transport.yml
+  hosts: tc-transport-unset
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].method
+      right: "ssh"
+
+- hosts: tc-transport-local
+  vars: {mitogen_via: tc-transport-unset}
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].method
+      right: "ssh"
+  - assert_equal:
+      left: out.result[1].method
+      right: "local"
+
+
+# ansible_connection=local
+
+- hosts: tc-transport-local
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].method
+      right: "local"
+
+- hosts: tc-transport-unset
+  vars: {mitogen_via: tc-transport-local}
+  tasks:
+  - include: ../_mitogen_only.yml
+  - {mitogen_get_stack: {}, register: out}
+  - assert_equal:
+      left: out.result[0].method
+      right: "local"
+  - assert_equal:
+      left: out.result[1].method
+      right: "ssh"