diff --git a/tackle/models.py b/tackle/models.py
index 55165387a..8a6e4e5df 100644
--- a/tackle/models.py
+++ b/tackle/models.py
@@ -38,8 +38,8 @@ class BaseContext(BaseModel):
     verbose: bool = False
 
     input_context: Union[dict, list] = None
-    public_context: Union[dict, list] = None
-    private_context: Union[dict, list] = None
+    public_context: Union[dict, list] = {}
+    private_context: Union[dict, list] = {}
     temporary_context: Union[dict, list] = None
     existing_context: dict = {}
     override_context: dict = Field({}, description="A dict to override inputs with.")
diff --git a/tackle/render.py b/tackle/render.py
index ad19ccad7..ca38e02d6 100644
--- a/tackle/render.py
+++ b/tackle/render.py
@@ -215,14 +215,33 @@ def render_string(context: 'Context', raw: str):
                 f"doesn't have arguments. Consider changing."
             )
 
-        # Check for ambiguous globals like `namespace` tackle/issues/19
+        # Check for ambiguous globals like `namespace`
+        # TODO: tackle/issues/19 -> This is hacky af... Need to redo this with visitor
         match = re.search(r'\<class \'(.+?)\'>', rendered_template)
         if match:
             ambiguous_key = match.group(1).split('.')[-1].lower()
-            if ambiguous_key in context.public_context:
-                rendered_template = context.public_context[ambiguous_key]
-            elif match.group(1) in context.existing_context:
-                rendered_template = context.existing_context[ambiguous_key]
+            if context.temporary_context and ambiguous_key in context.temporary_context:
+                ambiguous_key_rendered = context.temporary_context[ambiguous_key]
+            elif ambiguous_key in context.public_context:
+                ambiguous_key_rendered = context.public_context[ambiguous_key]
+            elif context.private_context and ambiguous_key in context.private_context:
+                ambiguous_key_rendered = context.private_context[ambiguous_key]
+            elif context.existing_context and ambiguous_key in context.existing_context:
+                ambiguous_key_rendered = context.existing_context[ambiguous_key]
+            else:
+                raise UnknownTemplateVariableException(
+                    f"Unknown ambiguous key {ambiguous_key}. Tracking issue at "
+                    f"tackle/issues/19",
+                    context=context,
+                ) from None
+            if isinstance(ambiguous_key_rendered, str):
+                rendered_template = (
+                    rendered_template[: match.regs[0][0]]
+                    + ambiguous_key_rendered
+                    + rendered_template[match.regs[0][1] :]
+                )
+            else:
+                rendered_template = ambiguous_key_rendered
 
     except TypeError as e:
         # Raised when the wrong type is provided to a hook
diff --git a/tests/render/fixtures/render-with-filters-output.yaml b/tests/render/fixtures/render-with-filters-output.yaml
new file mode 100644
index 000000000..35da52d26
--- /dev/null
+++ b/tests/render/fixtures/render-with-filters-output.yaml
@@ -0,0 +1,2 @@
+contract_name: Big Deal Token
+project_slug: Big_Deal_Token
diff --git a/tests/render/fixtures/render-with-filters.yaml b/tests/render/fixtures/render-with-filters.yaml
new file mode 100644
index 000000000..79325a84c
--- /dev/null
+++ b/tests/render/fixtures/render-with-filters.yaml
@@ -0,0 +1,3 @@
+
+contract_name: Big Deal Token
+project_slug->: var contract_name|replace(' ','_')|replace('-','_')|replace('.','_')|trim()
diff --git a/tests/render/test_render.py b/tests/render/test_render.py
index 4c1ff6bd7..30a886a0a 100644
--- a/tests/render/test_render.py
+++ b/tests/render/test_render.py
@@ -12,6 +12,7 @@
     # https://github.com/robcxyz/tackle/issues/19
     ({'dict': {'stuff': 'things'}}, '{{dict}}', {'stuff': 'things'}),
     ({'namespace': {'stuff': 'things'}}, '{{namespace}}', {'stuff': 'things'}),
+    ({'namespace': 'foo'}, '{{namespace}}bar', 'foobar'),
     # Normal
     ({'adict': {'stuff': 'things'}}, '{{adict}}', {'stuff': 'things'}),
     ({'list': ['stuff', 'things']}, '{{list}}', ['stuff', 'things']),
@@ -20,9 +21,9 @@
 ]
 
 
-@pytest.mark.parametrize("context,raw,expected_output", RENDERABLES)
-def test_render_string_inputs(context, raw, expected_output):
-    context = Context(public_context=context)
+@pytest.mark.parametrize("input_context,raw,expected_output", RENDERABLES)
+def test_render_string_inputs(input_context, raw, expected_output):
+    context = Context(public_context=input_context)
     output = render_string(context=context, raw=raw)
 
     assert output == expected_output
@@ -32,13 +33,14 @@ def test_render_string_inputs(context, raw, expected_output):
     # TODO: Not asserting - RM
     # ('multi-line-block.yaml', 'multi-line-block-output.yaml'),
     ('call-function.yaml', 'call-function-output.yaml'),
+    ('render-with-filters.yaml', 'render-with-filters-output.yaml'),
 ]
 
 
 @pytest.mark.parametrize("file,expected_output", FILES)
 def test_render_files(change_curdir_fixtures, file, expected_output):
     o = tackle(file)
-    expected_output = read_config_file(expected_output)
+    expected_output = dict(read_config_file(expected_output))
     assert o == expected_output