diff --git a/decision_protocol.py b/decision_protocol.py
index ed198e8..7d21b9f 100644
--- a/decision_protocol.py
+++ b/decision_protocol.py
@@ -3,7 +3,8 @@
 import math
 import re
 
-from decision_providers import DecisionError, probability, validate_answer
+from decision_providers import (DecisionError, probability, validate_answer,
+                                probability_decimals_for_model, probability_sum_valid)
 
 MAX_REQUEST_BYTES = 32000
 MAX_RESPONSE_BYTES = 131072
@@ -63,6 +64,7 @@ def validate_response(data, payload):
     if not isinstance(data, dict) or not isinstance(data.get('model'), str) or not data['model']:
         raise ValueError('Missing decision model.')
     answers = data.get('answers')
+    decimals = probability_decimals_for_model(data['model'])
     if not isinstance(answers, dict) or set(answers) != set(payload['questions']):
         raise ValueError('Missing or unexpected answers.')
     for key, question in payload['questions'].items():
@@ -74,7 +76,7 @@ def validate_response(data, payload):
             raise ValueError('Invalid confidence.')
         if kind == 'choice':
             try:
-                validate_answer(answer, list(question['criteria']))
+                validate_answer(answer, list(question['criteria']), probability_decimals=decimals)
             except DecisionError as exc:
                 raise ValueError('Invalid choice answer.') from exc
         elif kind == 'noul':
@@ -87,7 +89,8 @@ def validate_response(data, payload):
             probs = answer.get('probabilities')
             if probs is not None:
                 if (not isinstance(probs, dict) or set(probs) != {str(i) for i in range(len(question['criteria']))}
-                        or any(not probability(p) for p in probs.values()) or abs(sum(probs.values()) - 1) > 1e-6):
+                        or any(not probability(p) for p in probs.values())
+                        or not probability_sum_valid(probs.values(), decimal_places=decimals)):
                     raise ValueError('Invalid score distribution.')
     usage = data.get('usage') or {}
     if not isinstance(usage, dict):
diff --git a/decision_providers/__init__.py b/decision_providers/__init__.py
index ab25311..0030558 100644
--- a/decision_providers/__init__.py
+++ b/decision_providers/__init__.py
@@ -59,7 +59,30 @@ def probability(value):
     return type(value) in (int, float) and math.isfinite(value) and 0 <= value <= 1
 
 
-def validate_answer(answer, choices):
+def probability_decimals_for_model(model):
+    """TypeSafe displays probabilities to two decimals; other models stay strict."""
+    if isinstance(model, str) and re.fullmatch(r"jev-(?:latest|\d[\w.-]*)", model.rsplit('/', 1)[-1], re.I):
+        return 2
+    return None
+
+
+def probability_sum_valid(values, *, decimal_places=None):
+    values = list(values)
+    if not values or any(not probability(p) for p in values):
+        return False
+    if abs(math.fsum(values) - 1) <= 1e-6:
+        return True
+    # Permit only the declared display precision. Do not apply a blanket loose
+    # tolerance to arbitrary high-precision or malformed distributions.
+    if decimal_places != 2 or any(abs(p * 100 - round(p * 100)) > 1e-8 for p in values):
+        return False
+    half_step = .005
+    lower = math.fsum(max(0., p - half_step) for p in values)
+    upper = math.fsum(min(1., p + half_step) for p in values)
+    return lower <= 1 + 1e-12 and upper >= 1 - 1e-12
+
+
+def validate_answer(answer, choices, *, probability_decimals=None):
     if not isinstance(answer, dict) or answer.get("type") != "choice":
         raise DecisionError("invalid_response")
     selected = answer.get("choice")
@@ -73,10 +96,12 @@ def validate_answer(answer, choices):
     if distribution is not None:
         if (not isinstance(distribution, dict) or set(distribution) != set(choices)
                 or any(not probability(p) for p in distribution.values())
-                or abs(sum(distribution.values()) - 1) > 1e-6
+                or not probability_sum_valid(distribution.values(), decimal_places=probability_decimals)
                 or distribution[selected] + 1e-9 < max(distribution.values())):
             raise DecisionError("invalid_probabilities")
-        entropy = (-sum(p * math.log(p) for p in distribution.values() if p > 0)
+        # Preserve the reported probabilities; normalize only the derived entropy.
+        total = math.fsum(distribution.values())
+        entropy = (-sum((p / total) * math.log(p / total) for p in distribution.values() if p > 0)
                    / math.log(len(choices))) if len(choices) > 1 else 0.0
         entropy = max(0.0, min(1.0, entropy))
     return selected, distribution, confidence, entropy
diff --git a/decision_providers/jev.py b/decision_providers/jev.py
index f7757f0..76814ec 100644
--- a/decision_providers/jev.py
+++ b/decision_providers/jev.py
@@ -12,7 +12,7 @@
 
 import httpx
 
-from . import DecisionError, DecisionResult, validate_answer
+from . import DecisionError, DecisionResult, validate_answer, probability_decimals_for_model
 
 ENDPOINTS = {"openrouter": "https://openrouter.ai/api/alpha/decisions",
              "typesafe": "https://api.typesafe.ai/v1/systemone"}
@@ -108,7 +108,8 @@ def _parse(self, raw, request, started, attempts, had_unmetered_attempt):
             if not isinstance(model, str) or not model or len(model) > 160:
                 raise ValueError("Missing model")
             selected, probs, confidence, entropy = validate_answer(
-                data.get("answers", {}).get("selection"), [c.id for c in request.choices])
+                data.get("answers", {}).get("selection"), [c.id for c in request.choices],
+                probability_decimals=probability_decimals_for_model(model))
             return DecisionResult(selected, probs, confidence, entropy, self.transport, model,
                 (time.monotonic() - started) * 1000, None if had_unmetered_attempt else cost, tokens, attempts)
         except (ValueError, AttributeError, TypeError, DecisionError) as exc:
diff --git a/docs/decision-rounding.md b/docs/decision-rounding.md
new file mode 100644
index 0000000..19cfee3
--- /dev/null
+++ b/docs/decision-rounding.md
@@ -0,0 +1,24 @@
+# Jev probability display precision
+
+TypeSafe displays probabilities and scores to two decimal places. The maintained
+[AI SDK TypeSafe adapter](https://github.com/vercel/ai/blob/main/packages/typesafe-ai/src/typesafe-ai-evaluation-model.ts)
+declares `probabilityDecimals: 2` and preserves the native numbers. Consequently,
+a valid distribution can arrive as `0.33, 0.33, 0.33`, summing to `0.99`.
+
+The router previously required a sum within `1e-6` of one. That can reject a valid
+HTTP200 decision response and expose a public502. Live architecture tests found
+`bad_response` failures; their discarded response bodies do not establish that
+every observed failure had this cause. This patch fixes the independently
+reproducible compatibility defect, not generative-provider timeouts.
+
+For versioned Jev model identifiers and the mutable `jev-latest` alias
+(including vendor-prefixed forms of both), distributions whose values are displayed at two decimal places are accepted when their clipped
+rounding intervals jointly contain a unit mass. Each value still must be finite
+and within0..1; keys must match all requested choices; the selected choice must
+have maximal displayed probability. Unexplained mass errors and distributions
+with other precision retain strict validation. Other model families remain strict.
+
+Raw probabilities, scores, confidence and usage are unchanged. Only the derived
+normalized entropy uses the normalized displayed weights. The rule is shared by
+public Choice/Score responses, direct Jev selection and automatic-routing
+revalidation. Requests, deadlines, model policies and retry behavior do not change.
diff --git a/policy_selection.py b/policy_selection.py
index 39666af..fa0feac 100644
--- a/policy_selection.py
+++ b/policy_selection.py
@@ -11,7 +11,8 @@
 import uuid
 
 from auto_policies import CATALOG_VERSION, build_bundle, catalog, validate_constraints
-from decision_providers import DecisionChoice, DecisionError, DecisionRequest, validate_answer
+from decision_providers import (DecisionChoice, DecisionError, DecisionRequest, validate_answer,
+                                probability_decimals_for_model)
 from decision_providers.jev import JevDecisionProvider
 
 log = logging.getLogger(__name__)
@@ -188,7 +189,8 @@ def legal_policies():
                 result = await provider.decide(request, deadline=started + config["decision_timeout_ms"] / 1000)
             trace.update(cost_usd=result.cost_usd, attempts=result.attempts)
             selected_id, _, confidence, entropy = validate_answer({"type": "choice", "choice": result.selected_id,
-                "probabilities": result.probabilities, "confidence": result.confidence}, legal)
+                "probabilities": result.probabilities, "confidence": result.confidence}, legal,
+                probability_decimals=probability_decimals_for_model(result.model))
             trace.update(provider=result.provider, model=result.model, cost_usd=result.cost_usd,
                          confidence=confidence, normalized_entropy=entropy, attempts=result.attempts,
                          proposed_id=selected_id, disagrees_with_default=selected_id != "general")
diff --git a/tests/test_automatic_routing.py b/tests/test_automatic_routing.py
index 1576eb6..889fdf0 100644
--- a/tests/test_automatic_routing.py
+++ b/tests/test_automatic_routing.py
@@ -84,6 +84,21 @@ async def test_uncertainty_and_unknown_selection_fall_back(automatic_host):
         assert trace["selected_id"] == "general" and trace["fallback_reason"] == reason
 
 
+@pytest.mark.asyncio
+@pytest.mark.parametrize('model,selected', [('typesafe/jev-1.13-20260917', 'coding-agent'),
+                                          ('another-decision-model', 'general')])
+async def test_automatic_revalidation_respects_only_jev_display_precision(automatic_host, model, selected):
+    class Rounded:
+        async def decide(self, req, *, deadline):
+            probs = {c.id: .95 if c.id == 'coding-agent' else .02 for c in req.choices}
+            assert len(probs) == 3
+            return DecisionResult('coding-agent', probs, .95, None, 'test', model, 1, .001, 10, 1)
+    execution = {**compile_automatic(automatic_host, intent())["execution"], "automatic_mode": "active"}
+    _, trace = await select_policy(automatic_host, {}, execution, provider=Rounded())
+    assert trace['selected_id'] == selected
+    if selected == 'general':assert trace['fallback_reason'] == 'invalid_probabilities'
+
+
 @pytest.mark.asyncio
 async def test_mutated_policy_or_description_is_rejected_before_network(automatic_host):
     execution = compile_automatic(automatic_host, intent())["execution"]
diff --git a/tests/test_decision_rounding.py b/tests/test_decision_rounding.py
new file mode 100644
index 0000000..409b05c
--- /dev/null
+++ b/tests/test_decision_rounding.py
@@ -0,0 +1,90 @@
+import json
+import random
+import time
+
+import httpx
+import pytest
+
+from decision_protocol import validate_response
+from decision_providers import (DecisionChoice, DecisionError, DecisionRequest,
+                                probability_sum_valid, validate_answer)
+from decision_providers.jev import JevDecisionProvider
+
+
+def response(probabilities, model='typesafe/jev-1.13-20260917', kind='choice'):
+    choice = max(probabilities, key=probabilities.get)
+    answer = {'type': kind, 'probabilities': probabilities, 'confidence': .2}
+    answer.update({'choice': choice} if kind == 'choice' else {'score': 1.0})
+    return {'model': model, 'answers': {'q': answer}, 'usage': {'input_tokens': 10, 'cost': .000001}}
+
+
+def payload(keys, kind='choice'):
+    return {'state': 'Select an option', 'questions': {'q': {'type': kind, 'instructions': 'Select',
+        'criteria': {k: k for k in keys} if kind == 'choice' else list(keys)}}}
+
+
+@pytest.mark.parametrize('probs', [dict(a=.33, b=.33, c=.33), dict(a=.34, b=.34, c=.33),
+                                 {str(i): .03 for i in range(32)}])
+def test_rounded_jev_distribution_survives_without_modifying_values(probs):
+    data = response(probs)
+    accepted = validate_response(data, payload(probs))
+    assert accepted['answers']['q']['probabilities'] == probs
+    selected, raw, confidence, entropy = validate_answer(data['answers']['q'], list(probs), probability_decimals=2)
+    assert raw == probs and confidence == .2 and selected in probs
+    assert 0 <= entropy <= 1
+
+
+def test_rounding_does_not_relax_other_models_or_recorded_choices():
+    probs = dict(a=.33, b=.33, c=.33)
+    with pytest.raises(ValueError):
+        validate_response(response(probs, model='other-decision-model'), payload(probs))
+    with pytest.raises(DecisionError):
+        validate_answer(response(probs)['answers']['q'], list(probs))
+
+
+@pytest.mark.parametrize('probs', [dict(a=.3, b=.3, c=.3), dict(a=.4, b=.4, c=.4),
+                                 dict(a=.331, b=.331, c=.331), dict(a=0, b=0), dict(a=.99),
+                                 dict(a=-.01, b=1.01), dict(a=True, b=0), dict(a=float('nan'), b=1)])
+def test_unexplained_mass_missing_precision_and_invalid_values_still_rejected(probs):
+    with pytest.raises(ValueError):
+        validate_response(response(probs), payload(probs))
+
+
+def test_unknown_choice_missing_option_and_non_argmax_still_rejected():
+    probs = dict(a=.5, b=.25, c=.25)
+    for choice in ['missing', 'b']:
+        data = response(probs);data['answers']['q']['choice'] = choice
+        with pytest.raises(ValueError):validate_response(data, payload(probs))
+    with pytest.raises(ValueError):validate_response(response(dict(a=.5, b=.5)), payload(['a', 'b', 'c']))
+
+
+def test_rounded_score_distribution_has_the_same_mass_rule():
+    probs = {'0': .33, '1': .33, '2': .33}
+    result = validate_response(response(probs, kind='score'), payload(probs, kind='score'))
+    assert result['answers']['q']['probabilities'] == probs
+    with pytest.raises(ValueError):
+        validate_response(response({'0': .3, '1': .3, '2': .3}, kind='score'), payload(probs, kind='score'))
+
+
+def test_real_normalized_distributions_remain_valid_after_display_rounding():
+    rng = random.Random(921)
+    for count in range(1, 33):
+        for _ in range(40):
+            weights = [rng.random() for _ in range(count)]
+            total = sum(weights)
+            displayed = [round(value / total, 2) for value in weights]
+            assert probability_sum_valid(displayed, decimal_places=2)
+    assert not probability_sum_valid([0.] * 32, decimal_places=2)
+    assert not probability_sum_valid([.7] + [0.] * 31, decimal_places=2)
+
+
+@pytest.mark.asyncio
+async def test_direct_jev_provider_preserves_rounded_distribution_and_normalizes_only_entropy():
+    req = DecisionRequest('q', 'Choose', {}, tuple(DecisionChoice(k, k) for k in ['a', 'b', 'c']))
+    data = response(dict(a=.33, b=.33, c=.33))
+    data['answers']['selection'] = data['answers'].pop('q')
+    async with httpx.AsyncClient(transport=httpx.MockTransport(lambda request: httpx.Response(200, json=data))) as client:
+        result = await JevDecisionProvider('test-only', client=client).decide(req, deadline=time.monotonic() + 1)
+    assert result.probabilities == dict(a=.33, b=.33, c=.33)
+    assert result.normalized_entropy == pytest.approx(1.)
+    assert result.confidence == .2 and result.cost_usd == .000001
diff --git a/tests/test_decision_routing.py b/tests/test_decision_routing.py
index 834113e..88824cd 100644
--- a/tests/test_decision_routing.py
+++ b/tests/test_decision_routing.py
@@ -98,6 +98,23 @@ def test_primary_antseed_success_does_not_call_openrouter(routed):
     assert len(calls) == 1
 
 
+@pytest.mark.parametrize('antseed_status', [200, 503])
+def test_public_decisions_accept_jev_display_rounding(routed, monkeypatch, antseed_status):
+    import sys
+    payload = copy.deepcopy(PAYLOAD)
+    payload['questions']['team']['criteria']['operations'] = 'Operations'
+    answer = copy.deepcopy(ANSWER)
+    answer['answers']['team']['probabilities'] = {'billing': .33, 'technical': .33, 'operations': .33}
+    monkeypatch.setattr(sys.modules[__name__], 'PAYLOAD', payload)
+    monkeypatch.setattr(sys.modules[__name__], 'ANSWER', answer)
+    host, _, calls, behavior = routed
+    behavior['antseed_status'] = antseed_status
+    response = TestClient(create_app(host)).post('/v1/decisions', json={**payload, 'policy_ir': POLICY})
+    assert response.status_code == 200, response.text
+    assert response.json()['answers'] == answer['answers']
+    assert len(calls) == (1 if antseed_status == 200 else 2)
+
+
 def test_decision_state_and_null_criteria_survive_lua_and_fallback(routed, monkeypatch):
     import sys
     payload = copy.deepcopy(PAYLOAD)