diff --git a/pilot/ai_review.py b/pilot/ai_review.py
index 3575a8a..073da0e 100644
--- a/pilot/ai_review.py
+++ b/pilot/ai_review.py
@@ -68,10 +68,11 @@ _SHA_MARKER_RE = re.compile(r"<!-- pragent:sha=([0-9a-f]{7,40}) -->")
 AI_REVIEW_LABEL = "AI-REVIEW"
 # Opt-in label for the token-usage block. Read at render time — see pr_has_label.
 AI_USAGE_LABEL = "AI-USAGE"
-SEVERITIES = ("critical", "high", "medium", "low")
+SEVERITIES = ("critical", "high", "medium", "low", "trivial", "info")
 # Severity rank — higher = more severe. Used by `apply_repo_config` to drop
-# findings below `severity_threshold`. Critical=3, high=2, medium=1, low=0.
-SEVERITY_RANK = {"low": 0, "medium": 1, "high": 2, "critical": 3}
+# findings below `severity_threshold`. critical=4, high=3, medium=2, low=1,
+# trivial=0, info=-1.
+SEVERITY_RANK = {"info": -1, "trivial": 0, "low": 1, "medium": 2, "high": 3, "critical": 4}
 REPO_CONFIG_FILE = ".pr-review.json"
 
 # Style → (default max_findings, default severity_threshold). Strict is
@@ -957,6 +958,7 @@ _SEVERITY_EMOJI = {
     "high": "🔴",
     "medium": "🟡",
     "low": "🔵",
+    "trivial": "⚪",
     "info": "⚪",
     "nit": "⚪",
 }
diff --git a/tests/pilot/test_ai_review.py b/tests/pilot/test_ai_review.py
index 334a0b7..3ab2231 100644
--- a/tests/pilot/test_ai_review.py
+++ b/tests/pilot/test_ai_review.py
@@ -11,9 +11,11 @@ sys.path.insert(0, os.path.join(ROOT, "pilot"))
 
 import ai_review  # noqa: E402
 from ai_review import (  # noqa: E402
+    _SEVERITY_EMOJI,
     _balanced_json_substring,
     _extract_first_json_object,
     _last_balanced_json,
+    _normalize_finding,
     _render_collapsible_usage,
     build_user_prompt,
     compute_attribution,
@@ -28,6 +30,8 @@ from ai_review import (  # noqa: E402
     parse_text_blocks,
     prior_review_bodies,
     reviewed_shas,
+    SEVERITIES,
+    SEVERITY_RANK,
     split_findings,
     summary_bullets,
     truncate_diff,
@@ -1692,3 +1696,53 @@ def test_inline_comment_body_humanized_tokens():
     body = inline_comment_body(f)
     assert "🪙 ~17,303 (17.3K) tok" in body
 
+
+# ---------------------------------------------------------------------------
+# Severity levels — Task 4 (add trivial + info)
+# ---------------------------------------------------------------------------
+
+
+def test_severities_includes_trivial_and_info():
+    assert "trivial" in SEVERITIES
+    assert "info" in SEVERITIES
+
+
+def test_severity_rank_orders_new_levels():
+    assert SEVERITY_RANK["info"] < SEVERITY_RANK["trivial"] < SEVERITY_RANK["low"]
+
+
+def test_threshold_medium_keeps_low_below_trivial_below_info():
+    # medium+ threshold:
+    # medium (rank 2) → kept
+    # low (rank 1) → DROPPED
+    # trivial (rank 0) → DROPPED
+    # info (rank -1) → DROPPED
+    cfg = {"style": "lenient", "severity_threshold": "medium"}
+    findings = [
+        {"severity": "info", "path": "a", "line": 1, "problem": "", "fix": "", "suggestion": "", "reference": ""},
+        {"severity": "trivial", "path": "b", "line": 1, "problem": "", "fix": "", "suggestion": "", "reference": ""},
+        {"severity": "low", "path": "c", "line": 1, "problem": "", "fix": "", "suggestion": "", "reference": ""},
+        {"severity": "medium", "path": "d", "line": 1, "problem": "", "fix": "", "suggestion": "", "reference": ""},
+    ]
+    kept, dropped = ai_review.apply_repo_config(findings, cfg, changed_paths=["x.py"])
+    sev_kept = [f["severity"] for f in kept]
+    sev_dropped = [f["severity"] for f in dropped]
+    assert "info" in sev_dropped
+    assert "trivial" in sev_dropped
+    assert "low" in sev_dropped
+    assert "medium" in sev_kept
+    # and nothing else
+    assert len(kept) == 1
+
+
+def test_unknown_severity_still_normalizes_to_medium():
+    # Backward compat
+    n = _normalize_finding({"severity": "emergency", "path": "x", "line": 1, "problem": "p"})
+    assert n["severity"] == "medium"
+
+
+def test_emoji_for_trivial_and_info_is_neutral():
+    # The plan's emoji table maps trivial/info to ⚪
+    assert _SEVERITY_EMOJI["trivial"] == "⚪"
+    assert _SEVERITY_EMOJI["info"] == "⚪"
+