diff --git a/surfsense_backend/tests/unit/etl_pipeline/cache/test_eligibility.py b/surfsense_backend/tests/unit/etl_pipeline/cache/test_eligibility.py
new file mode 100644
index 000000000..99d8e67b6
--- /dev/null
+++ b/surfsense_backend/tests/unit/etl_pipeline/cache/test_eligibility.py
@@ -0,0 +1,88 @@
+"""What is allowed into the cache -- the gating rules, as pure logic.
+
+These rules decide whether a given upload may be served from / written to the
+parse cache. They live in a pure predicate so every branch (disabled, vision,
+no service, file category) is covered here without touching DB, storage, or the
+parser.
+"""
+
+from __future__ import annotations
+
+import pytest
+
+from app.etl_pipeline.cache.eligibility import is_parse_cacheable
+
+pytestmark = pytest.mark.unit
+
+
+def test_document_with_service_and_cache_on_is_cacheable():
+    assert is_parse_cacheable(
+        filename="report.pdf",
+        etl_service="LLAMACLOUD",
+        cache_enabled=True,
+        has_vision_llm=False,
+    )
+
+
+def test_disabled_cache_is_never_cacheable():
+    assert not is_parse_cacheable(
+        filename="report.pdf",
+        etl_service="LLAMACLOUD",
+        cache_enabled=False,
+        has_vision_llm=False,
+    )
+
+
+def test_vision_llm_run_is_not_cacheable():
+    # Vision appends model output not captured by the key; sharing it would leak
+    # one run's generated text into a plain parse of the same bytes.
+    assert not is_parse_cacheable(
+        filename="report.pdf",
+        etl_service="LLAMACLOUD",
+        cache_enabled=True,
+        has_vision_llm=True,
+    )
+
+
+@pytest.mark.parametrize("etl_service", [None, ""])
+def test_missing_etl_service_is_not_cacheable(etl_service):
+    assert not is_parse_cacheable(
+        filename="report.pdf",
+        etl_service=etl_service,
+        cache_enabled=True,
+        has_vision_llm=False,
+    )
+
+
+@pytest.mark.parametrize(
+    "filename",
+    ["paper.pdf", "memo.docx", "slides.pptx", "sheet.xlsx", "book.epub"],
+)
+def test_document_extensions_are_cacheable(filename):
+    assert is_parse_cacheable(
+        filename=filename,
+        etl_service="LLAMACLOUD",
+        cache_enabled=True,
+        has_vision_llm=False,
+    )
+
+
+@pytest.mark.parametrize(
+    "filename",
+    [
+        "notes.txt",  # plaintext
+        "readme.md",  # plaintext
+        "main.py",  # plaintext
+        "podcast.mp3",  # audio
+        "photo.png",  # image (vision path / fallback, not a shared doc parse)
+        "data.csv",  # direct-convert
+        "archive.xyz",  # unsupported
+    ],
+)
+def test_non_document_categories_are_not_cacheable(filename):
+    assert not is_parse_cacheable(
+        filename=filename,
+        etl_service="LLAMACLOUD",
+        cache_enabled=True,
+        has_vision_llm=False,
+    )