diff --git a/README.md b/README.md
index cfda3f413..7a0d5655e 100644
--- a/README.md
+++ b/README.md
@@ -301,6 +301,7 @@ for data augmentation:
 - `textattack.CharSwapAugmenter` augments text by substituting, deleting, inserting, and swapping adjacent characters
 - `textattack.EasyDataAugmenter` augments text with a combination of word insertions, substitutions and deletions.
 - `textattack.CheckListAugmenter` augments text by contraction/extension and by substituting names, locations, numbers.
+- `textattack.CLAREAugmenter` augments text by replacing, inserting, and merging with a pre-trained masked language model.
 
 #### Augmentation Command-Line Interface
 The easiest way to use our data augmentation tools is with `textattack augment <args>`. `textattack augment`
@@ -323,6 +324,9 @@ The command `textattack augment --csv examples.csv --input-column text --recipe
 will augment the `text` column by altering 10% of each example's words, generating twice as many augmentations as original inputs, and exclude the original inputs from the
 output CSV. (All of this will be saved to `augment.csv` by default.)
 
+> **Tip:** Just as running attacks interactively, you can also pass `--interactive` to augment samples inputted by the user to quickly try out different augmentation recipes!
+
+
 After augmentation, here are the contents of `augment.csv`:
 ```csv
 text,label
diff --git a/tests/sample_outputs/list_augmentation_recipes.txt b/tests/sample_outputs/list_augmentation_recipes.txt
index cbb2e83c5..3fa3f9351 100644
--- a/tests/sample_outputs/list_augmentation_recipes.txt
+++ b/tests/sample_outputs/list_augmentation_recipes.txt
@@ -1,5 +1,7 @@
 charswap (textattack.augmentation.CharSwapAugmenter)
 checklist (textattack.augmentation.CheckListAugmenter)
+clare (textattack.augmentation.CLAREAugmenter)
 eda (textattack.augmentation.EasyDataAugmenter)
 embedding (textattack.augmentation.EmbeddingAugmenter)
 wordnet (textattack.augmentation.WordNetAugmenter)
+
diff --git a/textattack/augmentation/__init__.py b/textattack/augmentation/__init__.py
index 628ea10a2..593f946d6 100644
--- a/textattack/augmentation/__init__.py
+++ b/textattack/augmentation/__init__.py
@@ -13,4 +13,5 @@
     EasyDataAugmenter,
     CheckListAugmenter,
     DeletionAugmenter,
+    CLAREAugmenter,
 )
diff --git a/textattack/augmentation/recipes.py b/textattack/augmentation/recipes.py
index 9bc6497b4..ec009f822 100644
--- a/textattack/augmentation/recipes.py
+++ b/textattack/augmentation/recipes.py
@@ -11,6 +11,7 @@
     RepeatModification,
     StopwordModification,
 )
+from textattack.constraints.semantics.sentence_encoders import UniversalSentenceEncoder
 
 from . import Augmenter
 
@@ -36,9 +37,7 @@ class EasyDataAugmenter(Augmenter):
     """
 
     def __init__(self, pct_words_to_swap=0.1, transformations_per_example=4):
-        assert (
-            pct_words_to_swap >= 0.0 and pct_words_to_swap <= 1.0
-        ), "pct_words_to_swap must be in [0., 1.]"
+        assert 0.0 <= pct_words_to_swap <= 1.0, "pct_words_to_swap must be in [0., 1.]"
         assert (
             transformations_per_example > 0
         ), "transformations_per_example must be a positive integer"
@@ -185,3 +184,67 @@ def __init__(self, **kwargs):
         constraints = [DEFAULT_CONSTRAINTS[0]]
 
         super().__init__(transformation, constraints=constraints, **kwargs)
+
+
+class CLAREAugmenter(Augmenter):
+    """Li, Zhang, Peng, Chen, Brockett, Sun, Dolan.
+
+    "Contextualized Perturbation for Textual Adversarial Attack" (Li et al., 2020)
+
+    https://arxiv.org/abs/2009.07502
+
+    CLARE builds on a pre-trained masked language model and modifies the inputs in a contextaware manner.
+    We propose three contextualized perturbations, Replace, Insert and Merge, allowing for generating outputs
+    of varied lengths.
+    """
+
+    def __init__(
+        self, model="distilroberta-base", tokenizer="distilroberta-base", **kwargs
+    ):
+        import transformers
+
+        from textattack.transformations import (
+            CompositeTransformation,
+            WordInsertionMaskedLM,
+            WordMergeMaskedLM,
+            WordSwapMaskedLM,
+        )
+
+        shared_masked_lm = transformers.AutoModelForCausalLM.from_pretrained(model)
+        shared_tokenizer = transformers.AutoTokenizer.from_pretrained(tokenizer)
+
+        transformation = CompositeTransformation(
+            [
+                WordSwapMaskedLM(
+                    method="bae",
+                    masked_language_model=shared_masked_lm,
+                    tokenizer=shared_tokenizer,
+                    max_candidates=50,
+                    min_confidence=5e-4,
+                ),
+                WordInsertionMaskedLM(
+                    masked_language_model=shared_masked_lm,
+                    tokenizer=shared_tokenizer,
+                    max_candidates=50,
+                    min_confidence=0.0,
+                ),
+                WordMergeMaskedLM(
+                    masked_language_model=shared_masked_lm,
+                    tokenizer=shared_tokenizer,
+                    max_candidates=50,
+                    min_confidence=5e-3,
+                ),
+            ]
+        )
+
+        use_constraint = UniversalSentenceEncoder(
+            threshold=0.7,
+            metric="cosine",
+            compare_against_original=True,
+            window_size=15,
+            skip_text_shorter_than_window=True,
+        )
+
+        constraints = DEFAULT_CONSTRAINTS + [use_constraint]
+
+        super().__init__(transformation, constraints=constraints, **kwargs)
diff --git a/textattack/commands/augment.py b/textattack/commands/augment.py
index 4dab1ba99..1ca6dbb74 100644
--- a/textattack/commands/augment.py
+++ b/textattack/commands/augment.py
@@ -21,6 +21,7 @@
     "charswap": "textattack.augmentation.CharSwapAugmenter",
     "eda": "textattack.augmentation.EasyDataAugmenter",
     "checklist": "textattack.augmentation.CheckListAugmenter",
+    "clare": "textattack.augmentation.CLAREAugmenter",
 }