diff --git a/src/observe/reporter.test.ts b/src/observe/reporter.test.ts
index dfc52286..f8dda214 100644
--- a/src/observe/reporter.test.ts
+++ b/src/observe/reporter.test.ts
@@ -105,6 +105,24 @@ describe('observeExporter', () => {
     expect(allEvents(posted).at(-1)?.type).toBe('agent.deregister');
   });
 
+  it('maps an ended span with unset status to ok', async () => {
+    const { r, posted } = reporter();
+    const span = makeSpan({ id: 'ended', endTime: 150 });
+    r.onSpanStart(span);
+    r.onSpanEnd(span);
+    await r.close();
+    expect(observations(posted).find((o) => o.data.obs_id === 'ended')?.data.status).toBe('ok');
+  });
+
+  it('keeps an open span status unset', async () => {
+    const { r, posted } = reporter();
+    const span = makeSpan({ id: 'open', endTime: undefined });
+    r.onSpanStart(span);
+    r.onSpanEnd(span);
+    await r.close();
+    expect(observations(posted).find((o) => o.data.obs_id === 'open')?.data.status).toBeUndefined();
+  });
+
   it('carries usage/cost/flags verbatim from gen_ai + lousho attrs', async () => {
     const { r, posted } = reporter();
     const span = makeSpan({
diff --git a/src/observe/reporter.ts b/src/observe/reporter.ts
index 4f665447..3be43b2f 100644
--- a/src/observe/reporter.ts
+++ b/src/observe/reporter.ts
@@ -154,7 +154,9 @@ const GENERIC_OUTPUT_KEYS = [GenAiAttr.OUTPUT_MESSAGES, LegacyAttr.RESULT] as co
 function observationOf(span: Span, traceId: string, agentId: string, fallbackSessionId: string, now: () => number): ObservationData {
   const attrs = span.attributes;
   const op = str(attrs[GenAiAttr.OPERATION_NAME]) ?? '';
-  const status = span.status?.code;
+  const code = span.status?.code;
+  // An ended span nobody marked failed succeeded; only a still-open span stays unset.
+  const status = code === 'error' ? 'error' : span.endTime !== undefined ? 'ok' : undefined;
   return {
     obs_id: span.id,
     trace_id: traceId,
@@ -165,7 +167,7 @@ function observationOf(span: Span, traceId: string, agentId: string, fallbackSes
     name: span.name,
     start: span.startTime,
     end: span.endTime ?? now(),
-    ...(status === 'ok' || status === 'error' ? { status } : {}),
+    ...(status !== undefined ? { status } : {}),
     ...(pickAttr(attrs, INPUT_KEYS[op] ?? GENERIC_INPUT_KEYS) !== undefined
       ? { input: pickAttr(attrs, INPUT_KEYS[op] ?? GENERIC_INPUT_KEYS) }
       : {}),