diff --git a/haiku_rag_slim/haiku/rag/doctor.py b/haiku_rag_slim/haiku/rag/doctor.py
index 71d1c1d1..4bbd48a2 100644
--- a/haiku_rag_slim/haiku/rag/doctor.py
+++ b/haiku_rag_slim/haiku/rag/doctor.py
@@ -548,17 +548,20 @@ def _check_vector_index(stats: dict) -> CheckResult:
     chunks = stats["chunks"]
     num_chunks = chunks.get("num_rows", 0)
     if not chunks.get("has_vector_index"):
-        if num_chunks >= 256:
+        if num_chunks >= 100_000:
             return CheckResult(
                 name="vector_index",
                 severity=Severity.WARN,
-                message="No vector index; similarity search falls back to a scan.",
+                message=(
+                    "No vector index on a large collection; "
+                    "similarity search scans every chunk and may be slow."
+                ),
                 remediation="haiku-rag create-index",
             )
         return CheckResult(
             name="vector_index",
             severity=Severity.OK,
-            message=f"No vector index yet (need {256 - num_chunks} more chunks).",
+            message="No vector index; similarity search is exact (brute-force).",
         )
     unindexed = chunks.get("num_unindexed_rows", 0)
     if unindexed > 0:
@@ -663,7 +666,7 @@ async def _probe_endpoint(
 
 
 def _endpoint_result(
-    url: str, entry: dict, reachable: bool, error: str | None, payload: dict | None
+    entry: dict, reachable: bool, error: str | None, payload: dict | None
 ) -> CheckResult:
     kind = entry["kind"]
     display = entry["display"]
@@ -709,9 +712,7 @@ async def run_provider_checks(config: AppConfig) -> list[CheckResult]:
                 *(_probe_endpoint(client, url) for url in targets)
             )
         for url, (reachable, error, payload) in zip(targets, probes):
-            results.append(
-                _endpoint_result(url, targets[url], reachable, error, payload)
-            )
+            results.append(_endpoint_result(targets[url], reachable, error, payload))
 
     for provider in sorted(local):
         results.append(
diff --git a/tests/test_doctor.py b/tests/test_doctor.py
index d9a6fa62..5ca7bef3 100644
--- a/tests/test_doctor.py
+++ b/tests/test_doctor.py
@@ -593,14 +593,21 @@ def test_embedding_drift_ok_without_stored_identity():
     assert _check_embedding_drift({}, _config()).severity is Severity.OK
 
 
-def test_vector_index_ok_below_threshold():
+def test_vector_index_ok_without_index_on_small_collection():
     stats = {"chunks": {"num_rows": 10, "has_vector_index": False}}
     assert _check_vector_index(stats).severity is Severity.OK
 
 
-def test_vector_index_warns_when_missing_above_threshold():
+def test_vector_index_ok_without_index_on_moderate_collection():
     stats = {"chunks": {"num_rows": 300, "has_vector_index": False}}
     result = _check_vector_index(stats)
+    assert result.severity is Severity.OK
+    assert result.remediation is None
+
+
+def test_vector_index_warns_for_large_collection_without_index():
+    stats = {"chunks": {"num_rows": 100_000, "has_vector_index": False}}
+    result = _check_vector_index(stats)
     assert result.severity is Severity.WARN
     assert result.remediation == "haiku-rag create-index"