diff --git a/src/fgai/dashboard.py b/src/fgai/dashboard.py
index aa9f307..2cb2991 100644
--- a/src/fgai/dashboard.py
+++ b/src/fgai/dashboard.py
@@ -182,9 +182,10 @@ function profileDiscoveryDetails(row) {
   }
   const selected = d.selected_fields || {};
   const top = (d.top_fields || []).slice(0,8).map(item => `${item.field} ${(Number(item.coverage || 0)*100).toFixed(0)}%/${item.unique_values}`).join(', ');
+  const shared = (d.shared_fields || row.shared_fields || []).slice(0,8).map(item => `${item.field} (${item.streams} streams)`).join(', ');
   const rejected = (d.rejected_fields || []).slice(0,8).map(item => `${item.field}: ${item.reason}`).join('; ');
   const reasons = (d.reasons || []).join('; ');
-  return `<details><summary>${esc(d.field_count)} fields analyzed</summary><p><b>Selected</b><br>Entity: ${esc((selected.entity || []).join(', ') || '-')}<br>Time: ${esc((selected.time || []).join(', ') || '-')}<br>Categorical: ${esc((selected.categorical || []).join(', ') || '-')}<br>Numeric: ${esc((selected.numeric || []).join(', ') || '-')}</p><p><b>Top fields</b><br>${esc(top || '-')}</p><p><b>Rejected</b><br>${esc(rejected || '-')}</p><p>${esc(reasons || '')}</p></details>`;
+  return `<details><summary>${esc(d.field_count)} fields analyzed</summary><p><b>Selected</b><br>Entity: ${esc((selected.entity || []).join(', ') || '-')}<br>Time: ${esc((selected.time || []).join(', ') || '-')}<br>Categorical: ${esc((selected.categorical || []).join(', ') || '-')}<br>Numeric: ${esc((selected.numeric || []).join(', ') || '-')}</p><p><b>Shared across streams</b><br>${esc(shared || '-')}</p><p><b>Top fields</b><br>${esc(top || '-')}</p><p><b>Rejected</b><br>${esc(rejected || '-')}</p><p>${esc(reasons || '')}</p></details>`;
 }
 function drawTrend(history) {
   const canvas=document.getElementById('trendChart'), ctx=canvas.getContext('2d'), ratio=window.devicePixelRatio||1, cw=canvas.clientWidth, ch=canvas.clientHeight;
diff --git a/src/fgai/llm.py b/src/fgai/llm.py
index f69307c..1f89679 100644
--- a/src/fgai/llm.py
+++ b/src/fgai/llm.py
@@ -94,6 +94,8 @@ def ollama_profile_advice(suggestions: list[dict[str, object]], model: str | Non
             "stream_name": item.get("stream_name"),
             "events": item.get("events"),
             "common_fields": item.get("common_fields", [])[:20],
+            "shared_fields": item.get("shared_fields", [])[:12],
+            "detected_log_type": item.get("detected_log_type", ""),
             "heuristic_profile": item.get("profile", {}),
         }
         for item in suggestions[:10]
@@ -110,7 +112,7 @@ def ollama_profile_advice(suggestions: list[dict[str, object]], model: str | Non
                 "{\"profiles\":[{\"stream_id\":\"...\",\"entity_fields\":[\"...\"],\"timestamp_field\":\"...\","
                 "\"categorical_fields\":[\"...\"],\"numeric_fields\":[\"...\"],\"detectors\":{\"auth_failure\":{\"enabled\":true,\"minimum\":5,\"z_threshold\":3}},"
                 "\"reason\":\"short reason\"}]}. "
-                "Use only field names present in common_fields or heuristic_profile. Do not include raw message/full_message fields. "
+                "Use only field names present in common_fields, shared_fields, or heuristic_profile. Prefer fields that appear in shared_fields when they are useful categorical or numeric baseline fields. Do not include raw message/full_message fields. "
                 "Allowed detectors are auth_failure, dns_query, deny_action. Prefer canonical fields such as username, hostname, eventid, srcip, dstip when present. "
                 f"\n\nObserved streams:\n{json.dumps(compact, sort_keys=True)}"
             ),
diff --git a/src/fgai/profile_suggestions.py b/src/fgai/profile_suggestions.py
index 1566631..89198b9 100644
--- a/src/fgai/profile_suggestions.py
+++ b/src/fgai/profile_suggestions.py
@@ -359,6 +359,35 @@ def _generic_numeric_fields(coverage: Counter[str], numeric_counts: Counter[str]
     return output
 
 
+def _shared_profile_fields(
+    coverage: Counter[str],
+    unique_values: dict[str, set[str]],
+    numeric_counts: Counter[str],
+    total: int,
+    stream_field_counts: Counter[str],
+) -> tuple[list[str], list[str], list[dict[str, object]]]:
+    categorical: list[str] = []
+    numeric: list[str] = []
+    stats: list[dict[str, object]] = []
+    for field, stream_count in stream_field_counts.most_common():
+        if stream_count < 2 or field in IGNORED_DISCOVERY_FIELDS or not coverage[field]:
+            continue
+        coverage_ratio = coverage[field] / max(1, total)
+        cardinality = len(unique_values[field])
+        if coverage_ratio < 0.1 or cardinality <= 1:
+            continue
+        if cardinality > min(200, max(8, int(total * 0.7))):
+            continue
+        numeric_ratio = numeric_counts[field] / max(1, coverage[field])
+        row = {"field": field, "streams": stream_count, "coverage": round(coverage_ratio, 2), "unique_values": cardinality}
+        stats.append(row)
+        if numeric_ratio >= 0.95:
+            numeric.append(field)
+        elif not _looks_like_entity_field(field) and not _looks_like_time_field(field):
+            categorical.append(field)
+    return categorical[:8], numeric[:5], stats[:12]
+
+
 def _allowed_fields(suggestion: dict[str, object]) -> set[str]:
     profile = suggestion.get("profile", {}) if isinstance(suggestion.get("profile"), dict) else {}
     fields = {str(item.get("field", "")) for item in suggestion.get("common_fields", []) if isinstance(item, dict)}
@@ -432,6 +461,15 @@ def suggest_stream_profiles(events: list[LogEvent], *, existing_profiles: dict[s
         stream_id = _stream_id(event)
         grouped[stream_id].append(event)
         names.setdefault(stream_id, _stream_name(event, stream_id))
+    stream_field_counts: Counter[str] = Counter()
+    for stream_events in grouped.values():
+        fields = {
+            field
+            for event in stream_events
+            for field, value in event.fields.items()
+            if field not in IGNORED_DISCOVERY_FIELDS and _has_discovery_value(value)
+        }
+        stream_field_counts.update(fields)
 
     suggestions: list[dict[str, object]] = []
     for stream_id, stream_events in grouped.items():
@@ -457,15 +495,18 @@ def suggest_stream_profiles(events: list[LogEvent], *, existing_profiles: dict[s
         entity_priority = WINDOWS_ENTITY_PRIORITY if is_windows else ENTITY_PRIORITY
         categorical_priority = WINDOWS_CATEGORICAL_PRIORITY if is_windows else CATEGORICAL_PRIORITY
         numeric_priority = WINDOWS_NUMERIC_PRIORITY if is_windows else NUMERIC_PRIORITY
+        shared_categorical, shared_numeric, shared_stats = _shared_profile_fields(coverage, unique_values, numeric_counts, total, stream_field_counts)
         entity_fields = _generic_entity_fields(coverage, unique_values, total, _pick_present(entity_priority, coverage, total, min_ratio=0.02, limit=12 if is_windows else 3))
         timestamp = next(iter(_pick_present(TIME_PRIORITY, coverage, total, min_ratio=0.02, limit=1)), "")
         if not timestamp:
             timestamp = next((field for field, count in coverage.most_common() if _looks_like_time_field(field) and count / max(1, total) >= 0.02), "timestamp")
-        categorical = _generic_categorical_fields(coverage, unique_values, total, _pick_present(categorical_priority, coverage, total, min_ratio=0.02, limit=10 if is_windows else 8))
+        categorical_seed = list(dict.fromkeys([*_pick_present(categorical_priority, coverage, total, min_ratio=0.02, limit=10 if is_windows else 8), *shared_categorical]))
+        categorical = _generic_categorical_fields(coverage, unique_values, total, categorical_seed)
         numeric_seed = [
             field for field in numeric_priority
             if coverage[field] and numeric_counts[field] / max(1, coverage[field]) >= 0.8
         ][:5]
+        numeric_seed = list(dict.fromkeys([*numeric_seed, *shared_numeric]))
         numeric = numeric_seed if is_windows else _generic_numeric_fields(coverage, numeric_counts, total, numeric_seed)
         if not entity_fields:
             entity_fields = [field for field, _count in coverage.most_common() if field not in IGNORED_DISCOVERY_FIELDS][:1]
@@ -522,10 +563,12 @@ def suggest_stream_profiles(events: list[LogEvent], *, existing_profiles: dict[s
                 "numeric": numeric,
             },
             "top_fields": _field_stats(coverage, unique_values, numeric_counts, total)[:16],
+            "shared_fields": shared_stats,
             "rejected_fields": _rejected_fields(coverage, unique_values, numeric_counts, total, selected_fields),
             "reasons": [
                 f"detected {log_type} log pattern",
                 f"selected {len(entity_fields)} entity field(s), {len(categorical)} categorical field(s), and {len(numeric)} numeric field(s)",
+                f"found {len(shared_stats)} field(s) that also appear in other enabled streams",
                 "ignored raw/internal, constant, sparse, and very high-cardinality fields",
             ],
         }
@@ -544,6 +587,7 @@ def suggest_stream_profiles(events: list[LogEvent], *, existing_profiles: dict[s
             "numeric_fields": numeric,
             "detectors": detectors,
             "common_fields": high_coverage,
+            "shared_fields": shared_stats,
             "discovery": discovery,
             "detected_log_type": log_type,
             "profile": {
diff --git a/tests/test_profile_suggestions.py b/tests/test_profile_suggestions.py
index 017f8f7..c176011 100644
--- a/tests/test_profile_suggestions.py
+++ b/tests/test_profile_suggestions.py
@@ -154,6 +154,30 @@ class ProfileSuggestionTests(unittest.TestCase):
         self.assertEqual(rejected["constant_field"], "constant value")
         self.assertEqual(rejected["request_id"], "too high cardinality")
 
+    def test_fields_shared_between_streams_are_default_profile_candidates(self):
+        events = []
+        for stream_id, stream_name in (("billing", "BillingApp"), ("orders", "OrdersApp")):
+            events.extend(
+                parse_log_line(
+                    f"fgai_stream_id={stream_id} fgai_stream={stream_name} actor_id=user{index % 6} "
+                    f"tenant_id=t{index % 3} workflow_state={'approved' if index % 2 else 'rejected'} "
+                    f"result_code=r{index % 4} latency_ms={index % 9} created_at=2026-06-29T10:00:{index:02d}Z"
+                )
+                for index in range(1, 30)
+            )
+
+        suggestions = {item["stream_id"]: item for item in suggest_stream_profiles(events)}
+
+        for suggestion in suggestions.values():
+            profile = suggestion["profile"]
+            shared = {item["field"] for item in suggestion["shared_fields"]}
+            self.assertIn("workflow_state", shared)
+            self.assertIn("result_code", shared)
+            self.assertIn("latency_ms", shared)
+            self.assertIn("workflow_state", profile["categorical_fields"])
+            self.assertIn("result_code", profile["categorical_fields"])
+            self.assertIn("latency_ms", profile["numeric_fields"])
+
     def test_applies_valid_llm_advice_and_rejects_unknown_fields(self):
         suggestion = suggest_stream_profiles([
             parse_log_line("fgai_stream_id=windows fgai_stream=Windows username=alice hostname=host01 eventid=4625 action=failure")