From 4419eec154e8c36ccc8f2aea25bd9cbdf04700fe Mon Sep 17 00:00:00 2001
From: Zach Groves <zach.groves@datadoghq.com>
Date: Thu, 4 Dec 2025 11:52:51 -0500
Subject: [PATCH 1/2] add source otel tag update

---
 .../llm_observability/evaluations/external_evaluations.md   | 6 ++++--
 .../instrumentation/otel_instrumentation.md                 | 2 +-
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/content/en/llm_observability/evaluations/external_evaluations.md b/content/en/llm_observability/evaluations/external_evaluations.md
index 3f64f0e81d2..b46addf399d 100644
--- a/content/en/llm_observability/evaluations/external_evaluations.md
+++ b/content/en/llm_observability/evaluations/external_evaluations.md
@@ -30,7 +30,7 @@ While LLM Observability provides a few out-of-the-box evaluations for your trace
 <div class="alert alert-info">
 
 - Evaluation labels must be unique for a given LLM application (<code>ml_app</code>) and organization.
-- External evaluations are not supported for [OpenTelemetry spans][5].
+- External evaluations are supported for [OpenTelemetry spans][5], but require adding the <code>source:otel</code> tag to your evaluation.
 
 </div>
 
@@ -93,7 +93,9 @@ You can use the evaluations API provided by LLM Observability to send evaluation
           "timestamp_ms": 1609479200,
           "metric_type": "score",
           "label": "Accuracy",
-          "score_value": 3
+          "score_value": 3,
+          // source:otel required only for OpenTelemetry spans
+          "tags": ["source:otel"]
         }
       ]
     }
diff --git a/content/en/llm_observability/instrumentation/otel_instrumentation.md b/content/en/llm_observability/instrumentation/otel_instrumentation.md
index 685cae372c3..4924dedc1d3 100644
--- a/content/en/llm_observability/instrumentation/otel_instrumentation.md
+++ b/content/en/llm_observability/instrumentation/otel_instrumentation.md
@@ -12,7 +12,7 @@ LLM Observability supports ingesting OpenTelemetry traces that follow the [OpenT
 - A [Datadog API key][2]
 - An application instrumented with OpenTelemetry that emits traces following the [OpenTelemetry 1.37+ semantic conventions for generative AI][1]
 
-<div class="alert alert-info"><a href="/llm_observability/evaluations/external_evaluations">External evaluations</a> in LLM Observability are not applied to OpenTelemetry spans. Evaluations are only available for spans generated with the Datadog LLM Observability SDK or submitted directly to the HTTP API intake.</div>
+<div class="alert alert-info">If sending <a href="/llm_observability/evaluations/external_evaluations">external evaluations</a> for OpenTelemetry spans, you must add the <code>source:otel</code> tag to your evaluation.</div>
 
 ## Setup
 

From 614e2ee63f4aa172e447a75542f22bfd9aa9b9e0 Mon Sep 17 00:00:00 2001
From: cecilia saixue wat-kim <cecilia.watt@datadoghq.com>
Date: Thu, 4 Dec 2025 14:43:46 -0800
Subject: [PATCH 2/2] Update otel_instrumentation.md

---
 .../llm_observability/instrumentation/otel_instrumentation.md   | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/content/en/llm_observability/instrumentation/otel_instrumentation.md b/content/en/llm_observability/instrumentation/otel_instrumentation.md
index 4924dedc1d3..1ee5dca056e 100644
--- a/content/en/llm_observability/instrumentation/otel_instrumentation.md
+++ b/content/en/llm_observability/instrumentation/otel_instrumentation.md
@@ -12,7 +12,7 @@ LLM Observability supports ingesting OpenTelemetry traces that follow the [OpenT
 - A [Datadog API key][2]
 - An application instrumented with OpenTelemetry that emits traces following the [OpenTelemetry 1.37+ semantic conventions for generative AI][1]
 
-<div class="alert alert-info">If sending <a href="/llm_observability/evaluations/external_evaluations">external evaluations</a> for OpenTelemetry spans, you must add the <code>source:otel</code> tag to your evaluation.</div>
+<div class="alert alert-info">If you are sending <a href="/llm_observability/evaluations/external_evaluations">external evaluations</a> for OpenTelemetry spans, you must add the <code>source:otel</code> tag to your evaluation.</div>
 
 ## Setup