diff --git a/agent/usage_pricing.py b/agent/usage_pricing.py
index 467b72931c2..fcf4f622834 100644
--- a/agent/usage_pricing.py
+++ b/agent/usage_pricing.py
@@ -370,6 +370,17 @@ _OFFICIAL_DOCS_PRICING: Dict[tuple[str, str], PricingEntry] = {
         source_url="https://api-docs.deepseek.com/quick_start/pricing",
         pricing_version="deepseek-pricing-2026-03-16",
     ),
+    (
+        "deepseek",
+        "deepseek-v4-pro",
+    ): PricingEntry(
+        input_cost_per_million=Decimal("1.74"),
+        output_cost_per_million=Decimal("3.48"),
+        cache_read_cost_per_million=Decimal("0.0145"),
+        source="official_docs_snapshot",
+        source_url="https://api-docs.deepseek.com/quick_start/pricing",
+        pricing_version="deepseek-pricing-2026-05-12",
+    ),
     # Google Gemini
     (
         "google",
diff --git a/tests/agent/test_usage_pricing.py b/tests/agent/test_usage_pricing.py
index 5daace97dea..5c84b124a2e 100644
--- a/tests/agent/test_usage_pricing.py
+++ b/tests/agent/test_usage_pricing.py
@@ -190,3 +190,37 @@ def test_custom_endpoint_models_api_pricing_is_supported(monkeypatch):
 
     assert float(entry.input_cost_per_million) == 0.5
     assert float(entry.output_cost_per_million) == 2.0
+
+
+def test_deepseek_v4_pro_pricing_entry_exists():
+    """Regression test: deepseek-v4-pro must have a pricing entry.
+
+    Before this fix, deepseek-v4-pro sessions showed as unknown cost
+    in hermes insights because the _OFFICIAL_DOCS_PRICING table had no
+    entry for that model.  See #24218.
+    """
+    entry = get_pricing_entry(
+        "deepseek-v4-pro",
+        provider="deepseek",
+    )
+
+    assert entry is not None
+    assert entry.input_cost_per_million is not None
+    assert entry.output_cost_per_million is not None
+    assert float(entry.input_cost_per_million) == 1.74
+    assert float(entry.output_cost_per_million) == 3.48
+    assert float(entry.cache_read_cost_per_million) == 0.0145
+
+
+def test_deepseek_v4_pro_estimate_usage_cost():
+    """Ensure deepseek-v4-pro sessions get a dollar estimate, not unknown."""
+    result = estimate_usage_cost(
+        "deepseek-v4-pro",
+        CanonicalUsage(input_tokens=1000000, output_tokens=500000),
+        provider="deepseek",
+    )
+
+    assert result.status == "estimated"
+    assert result.amount_usd is not None
+    # 1M input × $1.74/M + 500K output × $3.48/M = $1.74 + $1.74 = $3.48
+    assert float(result.amount_usd) == 3.48