diff --git a/conformance.toml b/conformance.toml
index f2579142..611699e1 100644
--- a/conformance.toml
+++ b/conformance.toml
@@ -846,10 +846,12 @@ note = "The SAVE-side enclosing_fan_out_lineage keying (pipeline-utilities §10.
 status = "not-yet"
 
 # Spec v0.82.0 (proposal 0087).  Conformance-adapter within-node
-# directive execution order (§8.3).  Not-yet; observability fixture 135
-# defers with it.
+# directive execution order (§8.3).  Implemented since 0.17.0;
+# observability fixture 135 pins it.
 [proposals."0087"]
-status = "not-yet"
+status = "implemented"
+since = "0.17.0"
+note = "Within-node directive execution order (conformance-adapter §8.3): a node's sibling directives execute in fixture-document order (mapping insertion order, not sorted-by-key). Python was already conformant -- the fixture loader uses yaml.safe_load, which preserves mapping insertion order, and the hand-built metadata driver (_apply_metadata_directives) iterates a node's directives in key order, so fixtures 043 / 045 (augment-then-capture vs capture-then-augment) already passed. This proposal ratifies that rule; the dedicated pin fixture observability/135 (the SAME two order-sensitive directives -- augment_metadata write + capture_invocation_metadata_into read -- in opposite document order across two cases, the captured snapshot diverging) is un-deferred and wired onto the existing metadata driver. No src change: the order-preserving load + key-order execution already satisfy §8.3, and a loader guard-comment pins the safe_load dependence per §8.2."
 
 # Spec v0.83.0 (proposal 0088).  Langfuse parallel-branches mapping
 # parity (observability §8.4.8).  Not-yet; observability fixture 136
diff --git a/tests/conformance/harness/loader.py b/tests/conformance/harness/loader.py
index fa2def43..0e1b3c99 100644
--- a/tests/conformance/harness/loader.py
+++ b/tests/conformance/harness/loader.py
@@ -68,6 +68,11 @@ def load_fixture(path: Path) -> Fixture:
     directives we haven't modelled yet.
     """
     with path.open() as f:
+        # yaml.safe_load preserves mapping insertion (document) order in
+        # Python, so a node's sibling directives keep their fixture order.
+        # Conformance-adapter §8.3 (proposal 0087) requires directives to
+        # execute in document order, and observability/135 pins the
+        # divergence -- do not swap in an order-losing loader.
         raw = yaml.safe_load(f)
     return _FIXTURE_ADAPTER.validate_python(raw)
 
diff --git a/tests/conformance/test_observability.py b/tests/conformance/test_observability.py
index bea8d2e3..fbd27e07 100644
--- a/tests/conformance/test_observability.py
+++ b/tests/conformance/test_observability.py
@@ -100,6 +100,14 @@ def _reset_otel_global_tracer_provider(restore_to: object) -> None:
         "044-get-invocation-metadata-fan-out-scoping",
         "045-get-invocation-metadata-retry-scoping",
         "046-get-invocation-metadata-outside-invocation",
+        # proposal 0087 (within-node directive execution order, spec
+        # v0.82.0). 135 places augment_metadata + capture_invocation_
+        # metadata_into in opposite document order across two cases; the
+        # captured snapshot diverges only if a node's sibling directives
+        # run in fixture order. Reuses the 043/045 metadata driver, which
+        # iterates node directives in key order -- see
+        # _apply_metadata_directives.
+        "135-within-node-directive-execution-order",
         "001-otel-basic-trace",
         "002-otel-subgraph-hierarchy",
         "003-otel-error-status",
@@ -384,12 +392,6 @@ def _reset_otel_global_tracer_provider(restore_to: object) -> None:
             "134-langfuse-nested-fan-out-parent-resolution",
         )
     },
-    # Proposal 0087 (within-node directive execution order, spec v0.82.0).
-    # The conformance-adapter document-order directive rule is unimplemented
-    # until a later v0.16.0 PR.
-    "135-within-node-directive-execution-order": (
-        "within-node directive execution order (proposal 0087) not-yet implemented"
-    ),
     # Proposal 0088 (Langfuse parallel-branches mapping parity, spec
     # v0.83.0). The §8.4.8 per-branch dispatch-span Langfuse observation is
     # unimplemented until a later v0.16.0 PR.
@@ -735,6 +737,7 @@ async def test_observability_fixture(fixture_path: Path) -> None:
         "044-get-invocation-metadata-fan-out-scoping",
         "045-get-invocation-metadata-retry-scoping",
         "046-get-invocation-metadata-outside-invocation",
+        "135-within-node-directive-execution-order",
     }:
         await _run_get_invocation_metadata_fixture(spec)
     else: