diff --git a/packages/opentelemetry-semantic-conventions-ai/opentelemetry/semconv_ai/__init__.py b/packages/opentelemetry-semantic-conventions-ai/opentelemetry/semconv_ai/__init__.py
index 24ea52decb..3dbe9fd7f3 100644
--- a/packages/opentelemetry-semantic-conventions-ai/opentelemetry/semconv_ai/__init__.py
+++ b/packages/opentelemetry-semantic-conventions-ai/opentelemetry/semconv_ai/__init__.py
@@ -137,11 +137,18 @@ class SpanAttributes:
 
     # Watson/genai LLM
     GEN_AI_WATSONX_DECODING_METHOD = "llm.watsonx.decoding_method"
+
     GEN_AI_WATSONX_RANDOM_SEED = "llm.watsonx.random_seed"
     GEN_AI_WATSONX_MAX_NEW_TOKENS = "llm.watsonx.max_new_tokens"
     GEN_AI_WATSONX_MIN_NEW_TOKENS = "llm.watsonx.min_new_tokens"
     GEN_AI_WATSONX_REPETITION_PENALTY = "llm.watsonx.repetition_penalty"
 
+    # External work receipt references (opt-in) - see issue 4340
+    AIPOU_WORK_RECEIPT_ID = "aipou.work_receipt_id"
+    AIPOU_EVIDENCE_CLASS = "aipou.evidence_class"
+    AIPOU_SCHEME = "aipou.scheme"
+    AIPOU_VALIDATION_STATUS = "aipou.validation_status"
+
     # -----------------------------------------------------------------------
     # Legacy LLM_* aliases (old names with original string values)
     # These constants were removed or renamed in v0.5.0.
diff --git a/packages/opentelemetry-semantic-conventions-ai/opentelemetry/semconv_ai/_testing.py b/packages/opentelemetry-semantic-conventions-ai/opentelemetry/semconv_ai/_testing.py
index 3f74ae78f0..19f5323d09 100644
--- a/packages/opentelemetry-semantic-conventions-ai/opentelemetry/semconv_ai/_testing.py
+++ b/packages/opentelemetry-semantic-conventions-ai/opentelemetry/semconv_ai/_testing.py
@@ -439,3 +439,27 @@ def test_watsonx_metrics_kept(self):
         assert Meters.LLM_WATSONX_COMPLETIONS_EXCEPTIONS == "llm.watsonx.completions.exceptions"
         assert Meters.LLM_WATSONX_COMPLETIONS_RESPONSES == "llm.watsonx.completions.responses"
         assert Meters.LLM_WATSONX_COMPLETIONS_TOKENS == "llm.watsonx.completions.tokens"
+# ---------------------------------------------------------------------------
+# SpanAttributes — AIPOU external work-receipt reference (opt-in, issue #4340)
+# ---------------------------------------------------------------------------
+
+
+class TestSpanAttributesAIPOU:
+    """
+    AIPOU (AI Proof of Us) work-receipt reference attributes. These are opt-in:
+    traces may carry a reference to an externally-issued, externally-validated
+    work receipt, but tracing must never derive or validate the receipt itself.
+    """
+
+    def test_aipou_work_receipt_id(self):
+        assert SpanAttributes.AIPOU_WORK_RECEIPT_ID == "aipou.work_receipt_id"
+
+    def test_aipou_evidence_class(self):
+        assert SpanAttributes.AIPOU_EVIDENCE_CLASS == "aipou.evidence_class"
+
+    def test_aipou_scheme(self):
+        assert SpanAttributes.AIPOU_SCHEME == "aipou.scheme"
+
+    def test_aipou_validation_status(self):
+        assert SpanAttributes.AIPOU_VALIDATION_STATUS == "aipou.validation_status"
+