From eddf75616ead9a63f882fbddec4a131787361389 Mon Sep 17 00:00:00 2001
From: Pepijn <pepijn@huggingface.co>
Date: Wed, 15 Jul 2026 16:04:26 +0200
Subject: [PATCH] fix(processor): serialize FAST token mapping

---
 src/lerobot/processor/tokenizer_processor.py |  2 ++
 tests/processor/test_tokenizer_processor.py  | 20 +++++++++++++++++++-
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/lerobot/processor/tokenizer_processor.py b/src/lerobot/processor/tokenizer_processor.py
index f11f9f87a..f45cd2cb4 100644
--- a/src/lerobot/processor/tokenizer_processor.py
+++ b/src/lerobot/processor/tokenizer_processor.py
@@ -565,6 +565,8 @@ class ActionTokenizerProcessorStep(ActionProcessorStep):
         config = {
             "trust_remote_code": self.trust_remote_code,
             "max_action_tokens": self.max_action_tokens,
+            "fast_skip_tokens": self.fast_skip_tokens,
+            "paligemma_tokenizer_name": self.paligemma_tokenizer_name,
         }
 
         # Only save tokenizer_name if it was used to create the tokenizer
diff --git a/tests/processor/test_tokenizer_processor.py b/tests/processor/test_tokenizer_processor.py
index 5708e6e81..0290ae78a 100644
--- a/tests/processor/test_tokenizer_processor.py
+++ b/tests/processor/test_tokenizer_processor.py
@@ -25,7 +25,7 @@ import pytest
 import torch
 
 from lerobot.configs.types import FeatureType, PipelineFeatureType, PolicyFeature
-from lerobot.processor import DataProcessorPipeline, TokenizerProcessorStep
+from lerobot.processor import ActionTokenizerProcessorStep, DataProcessorPipeline, TokenizerProcessorStep
 from lerobot.processor.converters import create_transition, identity_transition
 from lerobot.types import TransitionKey
 from lerobot.utils.constants import (
@@ -88,6 +88,24 @@ class MockTokenizer:
         return result
 
 
+def test_action_tokenizer_config_preserves_token_mapping():
+    processor = object.__new__(ActionTokenizerProcessorStep)
+    processor.trust_remote_code = True
+    processor.max_action_tokens = 384
+    processor.fast_skip_tokens = 64
+    processor.paligemma_tokenizer_name = "custom/paligemma"
+    processor.action_tokenizer_name = "custom/fast"
+    processor.action_tokenizer_input_object = None
+
+    assert processor.get_config() == {
+        "trust_remote_code": True,
+        "max_action_tokens": 384,
+        "fast_skip_tokens": 64,
+        "paligemma_tokenizer_name": "custom/paligemma",
+        "action_tokenizer_name": "custom/fast",
+    }
+
+
 @pytest.fixture
 def mock_tokenizer():
     """Provide a mock tokenizer for testing."""