diff --git a/docs/module-internals.md b/docs/module-internals.md
index 69deca3..684d5ae 100644
--- a/docs/module-internals.md
+++ b/docs/module-internals.md
@@ -1166,7 +1166,8 @@ entry point. Its NPZ schema contains only complex spectral filters, spatial
 templates, and thresholds; the runtime pins the Hub revision and SHA-256,
 rejects unknown fields and invalid shapes, and never loads pickles. The result
 has `watermark_truth="unknown"` even when a provider pattern matches. A
-simultaneous provider match abstains. Tests in
+simultaneous provider match abstains. `PROVIDERS` exports only the calibrated
+provider labels for callers that route processing from a source hint. Tests in
 `tests/test_source_classify_v2.py` cover the public seam and changed-threshold
 behavior; the [model card](image-source-hf/README.md) records the frozen
 aggregate evidence and limits. This does not change the earlier
diff --git a/src/remove_ai_watermarks/source_classify_v2.py b/src/remove_ai_watermarks/source_classify_v2.py
index ca2a00e..05e27d1 100644
--- a/src/remove_ai_watermarks/source_classify_v2.py
+++ b/src/remove_ai_watermarks/source_classify_v2.py
@@ -12,7 +12,7 @@ from functools import lru_cache
 from hashlib import file_digest
 from importlib import import_module
 from pathlib import Path
-from typing import TYPE_CHECKING, Any, Literal
+from typing import TYPE_CHECKING, Any, Literal, get_args
 
 if TYPE_CHECKING:
     from numpy.typing import NDArray
@@ -51,6 +51,7 @@ CLAIM = "likely image source/export pattern; not SynthID detection"
 
 SourceLabel = Literal["openai", "google", "unknown"]
 SourceReason = Literal["classified", "abstained", "conflict", "feature_unavailable"]
+PROVIDERS = tuple(label for label in get_args(SourceLabel) if label != "unknown")
 
 
 @dataclass(frozen=True)
diff --git a/tests/test_source_classify_v2.py b/tests/test_source_classify_v2.py
index cc5fd7d..8f61b68 100644
--- a/tests/test_source_classify_v2.py
+++ b/tests/test_source_classify_v2.py
@@ -61,6 +61,7 @@ def test_top_level_api_is_lazy_and_points_to_new_runtime() -> None:
 
     assert raiw.classify_image_source is model.classify_image_source
     assert raiw.ImageSourceClassification is model.ImageSourceClassification
+    assert model.PROVIDERS == ("openai", "google")
     assert len(model.WEIGHTS_REVISION) == 40
     assert all(character in "0123456789abcdef" for character in model.WEIGHTS_REVISION)