diff --git a/.github/workflows/phpunit-feature.yml b/.github/workflows/phpunit-feature.yml
index ccfc38983..913da8e59 100644
--- a/.github/workflows/phpunit-feature.yml
+++ b/.github/workflows/phpunit-feature.yml
@@ -353,7 +353,7 @@ jobs:
                 -w /app \
                 --entrypoint sh \
                 durable-workflow-server-corpus-validator \
-                -lc 'set -eu; tar --no-same-owner -xf - -C /app; cp -a /app/workflow-package /workflow; php scripts/ci/prepare-release-workflow-composer-metadata.php; composer update durable-workflow/workflow --with-dependencies --minimal-changes --no-install --no-scripts --no-autoloader --no-interaction --no-progress --prefer-dist; composer install --no-interaction --no-progress --prefer-dist; git --version; vendor/bin/phpunit --version; git rev-parse --verify "$CORPUS_BASE_REF^{commit}"; php scripts/ci/check-worker-openapi-evolution.php "$CORPUS_BASE_REF"; vendor/bin/phpunit tests/Feature tests/Unit/NexusContractTest.php tests/Unit/CodecRegressionCorpusTest.php tests/Unit/PhpunitFeatureWorkflowContractTest.php tests/Unit/OpenApiDocumentEvolutionTest.php tests/Unit/NamespaceConformanceRunnerContractTest.php tests/Unit/NamespaceRuntimeContractTest.php tests/Unit/SchedulesConformanceRunnerContractTest.php tests/Unit/SchedulesRuntimeContractTest.php tests/Unit/ServerParitySdkDirectionResponseSummaryTest.php tests/Unit/ServerParitySdkQueryTransportTest.php tests/Unit/ServerParitySdkUpdateTransportTest.php tests/Unit/ServerParityLockPressureRetryTest.php --no-progress --colors=never; vendor/bin/phpunit tests/Unit/ReleaseImageImmutabilityGuardTest.php --no-progress --colors=never; vendor/bin/phpunit tests/Unit/ReleaseImagePublishWorkflowContractTest.php --filter test_php_security_audits_fail_before_release_publication --no-progress --colors=never; python3 scripts/ci/validate-regression-corpus.py --base-ref "$CORPUS_BASE_REF" --verify-counterfactual'
+                -lc 'set -eu; tar --no-same-owner -xf - -C /app; cp -a /app/workflow-package /workflow; php scripts/ci/prepare-release-workflow-composer-metadata.php; composer update durable-workflow/workflow --with-dependencies --minimal-changes --no-install --no-scripts --no-autoloader --no-interaction --no-progress --prefer-dist; composer install --no-interaction --no-progress --prefer-dist; git --version; vendor/bin/phpunit --version; git rev-parse --verify "$CORPUS_BASE_REF^{commit}"; php scripts/ci/check-worker-openapi-evolution.php "$CORPUS_BASE_REF"; vendor/bin/phpunit tests/Feature tests/Unit/NexusContractTest.php tests/Unit/CodecRegressionCorpusTest.php tests/Unit/PhpunitFeatureWorkflowContractTest.php tests/Unit/OpenApiDocumentEvolutionTest.php tests/Unit/NamespaceConformanceRunnerContractTest.php tests/Unit/NamespaceRuntimeContractTest.php tests/Unit/SchedulesConformanceRunnerContractTest.php tests/Unit/SchedulesRuntimeContractTest.php tests/Unit/ServerParitySdkDirectionResponseSummaryTest.php tests/Unit/ServerParitySdkQueryTransportTest.php tests/Unit/ServerParitySdkUpdateTransportTest.php tests/Unit/ServerParityLockPressureRetryTest.php tests/Unit/ServerParityManyUpdatesRetryTest.php --no-progress --colors=never; vendor/bin/phpunit tests/Unit/ReleaseImageImmutabilityGuardTest.php --no-progress --colors=never; vendor/bin/phpunit tests/Unit/ReleaseImagePublishWorkflowContractTest.php --filter test_php_security_audits_fail_before_release_publication --no-progress --colors=never; python3 scripts/ci/validate-regression-corpus.py --base-ref "$CORPUS_BASE_REF" --verify-counterfactual'
 
       - name: Select production image qualification for changed build inputs
         id: image_inputs
diff --git a/.github/workflows/server-parity.yml b/.github/workflows/server-parity.yml
index b992a9218..076be942a 100644
--- a/.github/workflows/server-parity.yml
+++ b/.github/workflows/server-parity.yml
@@ -31,6 +31,7 @@ on:
       - tests/Fixtures/ServerParityNormalization/**
       - tests/Unit/ServerParityRunnerTest.mjs
       - tests/Unit/ServerParityRunnerBlockedExcerptTest.mjs
+      - tests/Unit/ServerParityProbeNotesTest.mjs
       - tests/Unit/ServerParitySdkDirectionLanesTest.mjs
       - tests/Unit/ServerParityCodecDeadlineCellsTest.mjs
       - tests/Unit/ServerParityArtifactSummaryTest.mjs
@@ -61,6 +62,7 @@ on:
       - tests/Unit/ServerParityConcurrentWaitsContractTest.mjs
       - tests/Unit/ServerParityContinueTransfersContractTest.mjs
       - tests/Unit/ServerParityLargeCommandBatchesContractTest.mjs
+      - tests/Unit/ServerParityManyUpdatesContractTest.mjs
       - tests/Unit/ServerParityStartSearchAttributesContractTest.mjs
       - tests/Unit/ServerParityQueryArgumentsContractTest.mjs
       - tests/Unit/ServerParityQueryContractArgumentsContractTest.mjs
@@ -1987,7 +1989,7 @@ jobs:
           bash scripts/ci/run-composer.sh --rm -v "$PWD:/source" -w /source -- \
             install --working-dir=scripts/conformance/server-parity --no-interaction --no-progress
           docker run --rm --user=1000:1000 --entrypoint node -v "$PWD:/source:ro" -w /source \
-            "$image" --test tests/Unit/ServerParityRunnerTest.mjs tests/Unit/ServerParityRunnerBlockedExcerptTest.mjs tests/Unit/ServerParitySdkDirectionLanesTest.mjs tests/Unit/ServerParityCodecDeadlineCellsTest.mjs tests/Unit/ServerParityCooperativeContractTest.mjs tests/Unit/ServerParityChildCancellationContractTest.mjs tests/Unit/ServerParityScheduleContractTest.mjs tests/Unit/ServerParityVisibilityContractTest.mjs tests/Unit/ServerParityAdmissionContractTest.mjs tests/Unit/ServerParityRoleTokenContractTest.mjs tests/Unit/ServerParityWorkerDeregistrationContractTest.mjs tests/Unit/ServerParitySearchAttributeContractTest.mjs tests/Unit/ServerParityWorkerListingContractTest.mjs tests/Unit/ServerParityWorkerReplacementContractTest.mjs tests/Unit/ServerParityPatchDeploymentContractTest.mjs tests/Unit/ServerParityWaitingHistoryContractTest.mjs tests/Unit/ServerParityTaskRetryContractTest.mjs tests/Unit/ServerParityPublishedPatchContractTest.mjs tests/Unit/ServerParityPublishedPatchTransportTest.mjs tests/Unit/ServerParityRecordFileTest.mjs tests/Unit/ServerParityFailureLocationTest.mjs tests/Unit/ServerParityFailureExcerptTest.mjs tests/Unit/ServerParityLateWorkflowCompletionContractTest.mjs tests/Unit/ServerParityStorageTestContractTest.mjs tests/Unit/ServerParitySchedulePoliciesContractTest.mjs tests/Unit/ServerParitySignalsBeforeWorkerContractTest.mjs tests/Unit/ServerParityScheduleCatalogContractTest.mjs tests/Unit/ServerParityOperatorMetricsContractTest.mjs tests/Unit/ServerParityActivityLeaseRenewalContractTest.mjs tests/Unit/ServerParityConcurrentWaitsContractTest.mjs tests/Unit/ServerParityContinueTransfersContractTest.mjs tests/Unit/ServerParityLargeCommandBatchesContractTest.mjs tests/Unit/ServerParityStartSearchAttributesContractTest.mjs tests/Unit/ServerParityQueryArgumentsContractTest.mjs tests/Unit/ServerParityQueryContractArgumentsContractTest.mjs tests/Unit/ServerParityParentCloseCancellationContractTest.mjs tests/Unit/ServerParityRecordLocalActivityContractTest.mjs tests/Unit/ServerParityActivityCancellationAckContractTest.mjs tests/Unit/ServerParityServiceCatalogContractTest.mjs tests/Unit/ServerParityServiceEndpointsContractTest.mjs tests/Unit/ServerParityServiceCallsContractTest.mjs tests/Unit/ServerParityWorkflowImportContractTest.mjs tests/Unit/ServerParityWaterlineImportContractTest.mjs tests/Unit/ServerParitySystemMetricsContractTest.mjs tests/Unit/ServerParityOperatorDashboardTypesContractTest.mjs tests/Unit/ServerParityPrometheusMetricsContractTest.mjs tests/Unit/ServerParityPayloadCleanupContractTest.mjs tests/Unit/ServerParityRepairPassContractTest.mjs tests/Unit/ServerParityClusterInfoContractTest.mjs tests/Unit/ServerParityNamespaceDeleteContractTest.mjs tests/Unit/ServerParityMessageStreamsContractTest.mjs tests/Unit/ServerParityCancellationScopesContractTest.mjs tests/Unit/ServerParityWorkflowPollRequestContractTest.mjs tests/Unit/ServerParityUpdateValidationContractTest.mjs tests/Unit/ServerParityFixtureSelectionTest.mjs tests/Unit/ServerParityUpdateValidationRetryTest.mjs tests/Unit/ServerParityKilledAuthorPollTest.mjs tests/Unit/ServerParityImagePullTest.mjs tests/Unit/ServerParityAdapterCacheTest.mjs tests/Unit/ServerParityWorkerSessionsContractTest.mjs tests/Unit/ServerParityWorkerSessionActivitiesContractTest.mjs tests/Unit/ServerParityNexusOperationsContractTest.mjs tests/Unit/ServerParityBridgeAdaptersContractTest.mjs tests/Unit/ServerParityWorkflowStreamWritesContractTest.mjs > parity-evidence/comparator-tests.txt
+            "$image" --test tests/Unit/ServerParityRunnerTest.mjs tests/Unit/ServerParityRunnerBlockedExcerptTest.mjs tests/Unit/ServerParityProbeNotesTest.mjs tests/Unit/ServerParitySdkDirectionLanesTest.mjs tests/Unit/ServerParityCodecDeadlineCellsTest.mjs tests/Unit/ServerParityCooperativeContractTest.mjs tests/Unit/ServerParityChildCancellationContractTest.mjs tests/Unit/ServerParityScheduleContractTest.mjs tests/Unit/ServerParityVisibilityContractTest.mjs tests/Unit/ServerParityAdmissionContractTest.mjs tests/Unit/ServerParityRoleTokenContractTest.mjs tests/Unit/ServerParityWorkerDeregistrationContractTest.mjs tests/Unit/ServerParitySearchAttributeContractTest.mjs tests/Unit/ServerParityWorkerListingContractTest.mjs tests/Unit/ServerParityWorkerReplacementContractTest.mjs tests/Unit/ServerParityPatchDeploymentContractTest.mjs tests/Unit/ServerParityWaitingHistoryContractTest.mjs tests/Unit/ServerParityTaskRetryContractTest.mjs tests/Unit/ServerParityPublishedPatchContractTest.mjs tests/Unit/ServerParityPublishedPatchTransportTest.mjs tests/Unit/ServerParityRecordFileTest.mjs tests/Unit/ServerParityFailureLocationTest.mjs tests/Unit/ServerParityFailureExcerptTest.mjs tests/Unit/ServerParityLateWorkflowCompletionContractTest.mjs tests/Unit/ServerParityStorageTestContractTest.mjs tests/Unit/ServerParitySchedulePoliciesContractTest.mjs tests/Unit/ServerParitySignalsBeforeWorkerContractTest.mjs tests/Unit/ServerParityScheduleCatalogContractTest.mjs tests/Unit/ServerParityOperatorMetricsContractTest.mjs tests/Unit/ServerParityActivityLeaseRenewalContractTest.mjs tests/Unit/ServerParityConcurrentWaitsContractTest.mjs tests/Unit/ServerParityContinueTransfersContractTest.mjs tests/Unit/ServerParityLargeCommandBatchesContractTest.mjs tests/Unit/ServerParityManyUpdatesContractTest.mjs tests/Unit/ServerParityStartSearchAttributesContractTest.mjs tests/Unit/ServerParityQueryArgumentsContractTest.mjs tests/Unit/ServerParityQueryContractArgumentsContractTest.mjs tests/Unit/ServerParityParentCloseCancellationContractTest.mjs tests/Unit/ServerParityRecordLocalActivityContractTest.mjs tests/Unit/ServerParityActivityCancellationAckContractTest.mjs tests/Unit/ServerParityServiceCatalogContractTest.mjs tests/Unit/ServerParityServiceEndpointsContractTest.mjs tests/Unit/ServerParityServiceCallsContractTest.mjs tests/Unit/ServerParityWorkflowImportContractTest.mjs tests/Unit/ServerParityWaterlineImportContractTest.mjs tests/Unit/ServerParitySystemMetricsContractTest.mjs tests/Unit/ServerParityOperatorDashboardTypesContractTest.mjs tests/Unit/ServerParityPrometheusMetricsContractTest.mjs tests/Unit/ServerParityPayloadCleanupContractTest.mjs tests/Unit/ServerParityRepairPassContractTest.mjs tests/Unit/ServerParityClusterInfoContractTest.mjs tests/Unit/ServerParityNamespaceDeleteContractTest.mjs tests/Unit/ServerParityMessageStreamsContractTest.mjs tests/Unit/ServerParityCancellationScopesContractTest.mjs tests/Unit/ServerParityWorkflowPollRequestContractTest.mjs tests/Unit/ServerParityUpdateValidationContractTest.mjs tests/Unit/ServerParityFixtureSelectionTest.mjs tests/Unit/ServerParityUpdateValidationRetryTest.mjs tests/Unit/ServerParityKilledAuthorPollTest.mjs tests/Unit/ServerParityImagePullTest.mjs tests/Unit/ServerParityAdapterCacheTest.mjs tests/Unit/ServerParityWorkerSessionsContractTest.mjs tests/Unit/ServerParityWorkerSessionActivitiesContractTest.mjs tests/Unit/ServerParityNexusOperationsContractTest.mjs tests/Unit/ServerParityBridgeAdaptersContractTest.mjs tests/Unit/ServerParityWorkflowStreamWritesContractTest.mjs > parity-evidence/comparator-tests.txt
           docker run --rm --user=1000:1000 --cpus=1 --memory=256m --memory-swap=256m \
             --network=none --entrypoint node -v "$PWD:/source:ro" -w /source \
             "$image" --test tests/Unit/ServerParityCodecDeadlineLoadTest.mjs > parity-evidence/codec-load-tests.txt
diff --git a/docs/rust-server-port-checkpoints/2026-10-29-many-updates.md b/docs/rust-server-port-checkpoints/2026-10-29-many-updates.md
new file mode 100644
index 000000000..0cf7dc484
--- /dev/null
+++ b/docs/rust-server-port-checkpoints/2026-10-29-many-updates.md
@@ -0,0 +1,34 @@
+# October 29, descriptions after more than 64 updates
+
+- **Before.** The October 23 change removed native's 64-update admission
+  cap ([update lifetime cap](2026-10-23-update-lifetime-cap.md)). The
+  update summary that describes a run's waits still stopped at 64 updates
+  (`update_summary.rs`): it read every update wait over the run's life,
+  `LIMIT 65`, and gave up past 64. A run that had taken 65 updates was
+  described with no wait (`wait_kind` null), though its signal wait was
+  still open.
+- **Contract** (published 2.11.5; `WorkflowController::show`, Workflow 2.15.1
+  `RunWaitView`, `StructuralLimits::pendingUpdateCountLimit`):
+  - only pending updates are bounded (500 by default);
+  - a run is described by its open waits, however many updates it has
+    taken;
+  - an accepted update that is still open is the run's wait
+    ("Waiting for update set").
+- **Fixture.** `many-updates`, raw worker HTTP on protocol 1.20 in a fresh
+  namespace. A run opens a signal wait and takes 65 updates. Each is
+  accepted (202), delivered on its own workflow task and completed (200,
+  run waiting). The probe records:
+  - the description before and after the updates (`signal`);
+  - with a 66th update left accepted (`update`);
+  - the history counts (66 `UpdateAccepted`, 65 `UpdateCompleted`).
+
+  The worker heartbeats every 20 seconds, since the loop outlasts the
+  worker staleness window. The run is terminated after recording, so its
+  never-polled update task does not stay for later fixtures. The probe declares a 180-second budget; locally it took
+  about 80 seconds against published PHP.
+- **Native.** The summary keeps every accepted update and reads every
+  update wait. Only one open update at a time is described, as before.
+- **Not covered here.** The child summary still stops at 100 children
+  over a run's life (`child_summary.rs`); that needs its own fixture.
+- **Tests.** `many_updates.rs` fails on the previous source (`wait_kind`
+  null after 65 updates) and passes now.
diff --git a/docs/rust-server-port.md b/docs/rust-server-port.md
index 7c045ddcd..fc0a49070 100644
--- a/docs/rust-server-port.md
+++ b/docs/rust-server-port.md
@@ -578,6 +578,16 @@ contract fixture before its correction.
   150 timers, 150 activities, a 150-member group and a 1,001-member group
   against published 2.11.5
   ([checkpoint](rust-server-port-checkpoints/2026-10-29-large-command-batches.md)).
+- **Descriptions after more than 64 updates** (October 29, closed).
+  Published PHP bounds only pending updates, not how many a run takes over
+  its life. The October 23 change removed native's 64-update admission cap,
+  but its update summary still gave up past 64 updates. A run that had
+  taken 65 was described with no wait. The bound is removed. The
+  `many-updates` fixture records a run waiting for a signal through 65
+  completed updates, then a 66th left accepted, against published 2.11.5
+  ([checkpoint](rust-server-port-checkpoints/2026-10-29-many-updates.md)).
+  The child summary still stops at 100 children over a run's life; that
+  needs its own fixture.
 - **Trace context (Core 2.10, published in Server 2.11.1).** Core adds
   nullable `observability_context` columns on runs, commands and tasks.
   Native has no carrier: it accepts and ignores a top-level carrier on
@@ -667,9 +677,6 @@ contract fixture before its correction.
   `none` driver or database runtime credentials, which published PHP does
   not. Without a tenant-bound administrator, native does not read a namespace
   route's target from a JSON body `name`.
-- **Described command previews.** Published PHP's run description gives
-  each command `payload_preview_omitted` and, for a cancel or terminate, its
-  decoded `reason`. Native's described commands carry neither.
 - **Command route names.** Published PHP records each request's route name in
   its command context, and its unnamed workflow routes get a name generated
   per deployment. Native records names only for the named schedule routes.
diff --git a/rust/src/runtime/update_summary.rs b/rust/src/runtime/update_summary.rs
index fe001f9fc..691b86d81 100644
--- a/rust/src/runtime/update_summary.rs
+++ b/rust/src/runtime/update_summary.rs
@@ -54,8 +54,9 @@ impl UpdateSummaryHistory {
             return false;
         }
         if kind == "UpdateAccepted" {
-            if self.updates.len() >= 64
-                || self.updates.contains_key(id)
+            // Published PHP bounds only pending updates, not how many a
+            // run takes over its life, so every accepted update is kept.
+            if self.updates.contains_key(id)
                 // A run continued from a predecessor takes its pending update
                 // without an ordering state, ready for delivery.
                 || payload.get("ordering_state").is_some_and(|state| state != "ready")
@@ -132,9 +133,9 @@ where
         history: &UpdateSummaryHistory,
         summary: &mut ActiveSummary,
     ) -> Result<bool> {
-        let rows = Self::query("SELECT w.*,u.id AS update_id,u.workflow_command_id,u.workflow_instance_id AS update_instance,u.update_name,u.status AS update_status,u.command_sequence AS update_command_sequence,u.workflow_sequence,c.id AS matched_command_id,c.command_sequence AS matched_command_sequence FROM workflow_run_waits w LEFT JOIN workflow_updates u ON u.id=w.resume_source_id AND u.workflow_run_id=w.workflow_run_id LEFT JOIN workflow_commands c ON c.id=u.workflow_command_id AND c.workflow_run_id=w.workflow_run_id WHERE w.workflow_run_id=$1 AND w.kind='update' ORDER BY w.command_sequence,w.wait_id LIMIT 65")
+        let rows = Self::query("SELECT w.*,u.id AS update_id,u.workflow_command_id,u.workflow_instance_id AS update_instance,u.update_name,u.status AS update_status,u.command_sequence AS update_command_sequence,u.workflow_sequence,c.id AS matched_command_id,c.command_sequence AS matched_command_sequence FROM workflow_run_waits w LEFT JOIN workflow_updates u ON u.id=w.resume_source_id AND u.workflow_run_id=w.workflow_run_id LEFT JOIN workflow_commands c ON c.id=u.workflow_command_id AND c.workflow_run_id=w.workflow_run_id WHERE w.workflow_run_id=$1 AND w.kind='update' ORDER BY w.command_sequence,w.wait_id")
             .bind(run).fetch_all(&mut **tx).await?;
-        if rows.len() != history.updates.len() || rows.len() > 64 {
+        if rows.len() != history.updates.len() {
             return Ok(false);
         }
         let mut open = None;
diff --git a/rust/tests/execution.rs b/rust/tests/execution.rs
index 769a92b15..482ece65b 100644
--- a/rust/tests/execution.rs
+++ b/rust/tests/execution.rs
@@ -336,6 +336,8 @@ mod workflow_import_fences;
 
 #[path = "execution/large_command_batches.rs"]
 mod large_command_batches;
+#[path = "execution/many_updates.rs"]
+mod many_updates;
 
 #[path = "execution/query_argument_routing.rs"]
 mod query_argument_routing;
diff --git a/rust/tests/execution/many_updates.rs b/rust/tests/execution/many_updates.rs
new file mode 100644
index 000000000..81bcea0a3
--- /dev/null
+++ b/rust/tests/execution/many_updates.rs
@@ -0,0 +1,43 @@
+use super::*;
+
+// Published Server 2.11.5 bounds only pending updates
+// (DW_V2_LIMIT_PENDING_UPDATES), not how many a run takes over its life, and
+// describes a run by its open waits. The many-updates fixture records a run
+// waiting for a signal through 65 completed updates, then a 66th left
+// accepted.
+
+async fn describe(app: &Router) -> (Value, Value) {
+    let (_, described) = request(app, "GET", "/api/workflows/many-updates", Value::Null).await;
+    (described["wait_kind"].clone(), described["wait_reason"].clone())
+}
+
+#[tokio::test]
+async fn a_run_is_described_by_its_waits_after_more_than_64_updates() {
+    let database = TestDatabase::new().await;
+    let runtime = database.open().await.unwrap();
+    let app = router(runtime.clone());
+    update_worker(&app, "update-worker").await;
+    start(&app, "many-updates").await;
+    open_update_wait(&app, "update-worker").await;
+    let path = "/api/workflows/many-updates/update/set";
+    for index in 0..65 {
+        let (status, beat) = request(&app, "POST", "/api/worker/heartbeat", json!({"worker_id":"update-worker"})).await;
+        assert_eq!(status, StatusCode::OK, "{beat}");
+        let receipt = request(&app, "POST", path, json!({"input":envelope(Payload::Array(vec![Payload::Long(index)])),
+            "request_id":format!("many:{index}"),"wait_for":"accepted"})).await;
+        assert_eq!(receipt.0, StatusCode::ACCEPTED, "{}", receipt.1);
+        let task = poll(&app, "update-worker", "workflow").await;
+        assert_eq!(task["workflow_update_id"], receipt.1["update_id"]);
+        let result = request(&app, "POST", &format!("/api/worker/workflow-tasks/{}/complete", task["task_id"].as_str().unwrap()),
+            completion(&task, json!([{"type":"complete_update","update_id":receipt.1["update_id"],
+                "result":envelope(Payload::Long(index))}]))).await;
+        assert_eq!(result.0, StatusCode::OK, "{}", result.1);
+    }
+    assert_eq!(describe(&app).await, (json!("signal"), json!("Waiting for signal finish")));
+    let pending = request(&app, "POST", path, json!({"input":envelope(Payload::Array(vec![Payload::Long(65)])),
+        "request_id":"many:65","wait_for":"accepted"})).await;
+    assert_eq!(pending.0, StatusCode::ACCEPTED, "{}", pending.1);
+    assert_eq!(describe(&app).await, (json!("update"), json!("Waiting for update set")));
+    runtime.close().await;
+    database.remove().await;
+}
diff --git a/scripts/conformance/server-parity.mjs b/scripts/conformance/server-parity.mjs
index baa25fbd8..72929465a 100644
--- a/scripts/conformance/server-parity.mjs
+++ b/scripts/conformance/server-parity.mjs
@@ -13,7 +13,7 @@ import {parseDatabaseResourceLimits} from './server-parity/database-resource-con
 import {checkSdkChildDirectionArtifacts, checkSdkChildDirectionPackages} from './server-parity/sdk-child-direction-contract.mjs';
 import {checkSdkTimerAuthorArtifacts, checkSdkTimerAuthorPackages} from './server-parity/sdk-timer-author-contract.mjs';
 import {checkSdkSignalDirectionArtifacts, checkSdkSignalDirectionPackages} from './server-parity/sdk-signal-direction-contract.mjs';
-import {captureProbe} from './server-parity/probe-capture.mjs';
+import {captureProbe, probeNotes} from './server-parity/probe-capture.mjs';
 import {selectFixturePaths} from './server-parity/fixture-selection.mjs';
 import {writeRecord} from './server-parity/record-file.mjs';
 import {checkCorrectedMarkerArtifacts, checkCorrectedMarkerPackages} from './server-parity/corrected-marker-contract.mjs';
@@ -105,10 +105,16 @@ try {
         for (const flag of ['url', 'application-root']) {
           if (values[flag]) arguments_.push(`--${flag}`, values[flag]);
         }
-        const probe = captureProbe('php', arguments_, {directory: dirname(resolve(values.output)), timeout: fixture.memo_replay ? fixture.memo_replay.overall_budget_seconds * 1000 + 5000 : fixture.corrected_markers ? fixture.corrected_markers.overall_budget_seconds * 1000 + 5000 : fixture.namespace_signal_pair || fixture.selected_run_signal_pair || fixture.cancellation_scopes ? 75000 : fixture.update_validation ? 90000 : fixture.worker_poll_fence ? fixture.worker_poll_fence.overall_budget_seconds * 1000 + 5000 : fixture.worker_sessions ? fixture.worker_sessions.overall_budget_seconds * 1000 + 5000 : fixture.worker_session_activities ? fixture.worker_session_activities.overall_budget_seconds * 1000 + 5000 : fixture.large_command_batches ? fixture.large_command_batches.overall_budget_seconds * 1000 + 5000 : 45000,
+        const probe = captureProbe('php', arguments_, {directory: dirname(resolve(values.output)), timeout: fixture.memo_replay ? fixture.memo_replay.overall_budget_seconds * 1000 + 5000 : fixture.corrected_markers ? fixture.corrected_markers.overall_budget_seconds * 1000 + 5000 : fixture.namespace_signal_pair || fixture.selected_run_signal_pair || fixture.cancellation_scopes ? 75000 : fixture.update_validation ? 90000 : fixture.worker_poll_fence ? fixture.worker_poll_fence.overall_budget_seconds * 1000 + 5000 : fixture.worker_sessions ? fixture.worker_sessions.overall_budget_seconds * 1000 + 5000 : fixture.worker_session_activities ? fixture.worker_session_activities.overall_budget_seconds * 1000 + 5000 : fixture.large_command_batches ? fixture.large_command_batches.overall_budget_seconds * 1000 + 5000 : fixture.many_updates ? fixture.many_updates.overall_budget_seconds * 1000 + 5000 : 45000,
           env: {...process.env, DW_PARITY_FAILURE_EVIDENCE_DIR: dirname(resolve(values.output))},
           preserveStdout: join(sourceDirectory, name)});
         const item = {fixture_id: fixture.id, fixture, outcome: 'runner-blocked'};
+        // Recognized diagnostics are kept even when the probe succeeds.
+        const notes = probeNotes(probe.stderr);
+        if (notes.length > 0) {
+          item.probe_notes = notes;
+          for (const note of notes) console.error(`${fixture.id}: ${note}`);
+        }
         originals.set(item, {fixture: path, observation: probe.stdoutPath});
         try {
           if (probe.error || probe.status !== 0) throw new Error(probe.error?.message ?? probe.stderr.trim());
diff --git a/scripts/conformance/server-parity/contract.mjs b/scripts/conformance/server-parity/contract.mjs
index e3d86efa5..bd1985d57 100644
--- a/scripts/conformance/server-parity/contract.mjs
+++ b/scripts/conformance/server-parity/contract.mjs
@@ -16,6 +16,7 @@ import {checkActivityLeaseRenewal} from './activity-lease-renewal-contract.mjs';
 import {checkConcurrentWaits} from './concurrent-waits-contract.mjs';
 import {checkContinueTransfers} from './continue-transfers-contract.mjs';
 import {checkLargeCommandBatches} from './large-command-batches-contract.mjs';
+import {checkManyUpdates} from './many-updates-contract.mjs';
 import {checkStartSearchAttributes} from './start-search-attributes-contract.mjs';
 import {checkQueryArgumentRouting} from './query-arguments-contract.mjs';
 import {checkQueryContractArguments} from './query-contract-arguments-contract.mjs';
@@ -177,6 +178,7 @@ export function checkObservation(fixture, observation, workflowId, artifacts) {
   const concurrentWaits = fixture.concurrent_waits ? checkConcurrentWaits(fixture, observation) : null;
   const continueTransfers = fixture.continue_transfers ? checkContinueTransfers(fixture, observation) : null;
   const largeCommandBatches = fixture.large_command_batches ? checkLargeCommandBatches(fixture, observation) : null;
+  const manyUpdates = fixture.many_updates ? checkManyUpdates(fixture, observation) : null;
   const startSearchAttributes = fixture.start_search_attributes ? checkStartSearchAttributes(fixture, observation) : null;
   const queryArguments = fixture.query_argument_routing ? checkQueryArgumentRouting(fixture, observation) : null;
   const queryContractArguments = fixture.query_contract_arguments ? checkQueryContractArguments(fixture, observation) : null;
@@ -756,6 +758,7 @@ export function checkObservation(fixture, observation, workflowId, artifacts) {
     ...(concurrentWaits ? {concurrent_waits: concurrentWaits} : {}),
     ...(continueTransfers ? {continue_transfers: continueTransfers} : {}),
     ...(largeCommandBatches ? {large_command_batches: largeCommandBatches} : {}),
+    ...(manyUpdates ? {many_updates: manyUpdates} : {}),
     ...(startSearchAttributes ? {start_search_attributes: startSearchAttributes} : {}),
     ...(queryArguments ? {query_argument_routing: queryArguments} : {}),
     ...(queryContractArguments ? {query_contract_arguments: queryContractArguments} : {}),
diff --git a/scripts/conformance/server-parity/failure-excerpt.mjs b/scripts/conformance/server-parity/failure-excerpt.mjs
index be561541b..dd8f8d737 100644
--- a/scripts/conformance/server-parity/failure-excerpt.mjs
+++ b/scripts/conformance/server-parity/failure-excerpt.mjs
@@ -45,6 +45,10 @@ function walk(value, path, out, limit) {
   }
   if (typeof value.method === 'string' && typeof value.path === 'string' && Object.hasOwn(value, 'status')) {
     out.push(line(path, value));
+  } else if (typeof value.request === 'string' && /^[A-Z]+ \S+$/.test(value.request) && Number.isInteger(value.status)) {
+    // Older probes record a step as {request: 'METHOD path', status, response};
+    // the label and status are kept, the response body is not.
+    out.push(`${path} ${value.request.slice(0, 200)} ${value.status}`);
   }
   const tasks = value.tables?.workflow_tasks?.rows;
   if (Array.isArray(tasks)) {
diff --git a/scripts/conformance/server-parity/many-updates-contract.mjs b/scripts/conformance/server-parity/many-updates-contract.mjs
new file mode 100644
index 000000000..f8f591966
--- /dev/null
+++ b/scripts/conformance/server-parity/many-updates-contract.mjs
@@ -0,0 +1,26 @@
+import assert from 'node:assert/strict';
+
+// Reviewed descriptions after more than 64 updates (many-updates-probe.php),
+// recorded against published Server 2.11.5: a run waiting for a signal takes
+// 65 updates, each accepted and completed by its own workflow task, and is
+// still described as waiting for the signal; one more update left accepted
+// is described as the run's open update. The fixture's `expected` holds the
+// whole observation.
+export function checkManyUpdates(fixture, observation) {
+  const definition = fixture.many_updates;
+  const state = observation.many_updates;
+  const projection = {scope: 'many_updates', steps: Object.keys(definition.expected).length};
+  assert.ok(state && typeof state === 'object', 'actual many updates observation');
+  if (observation.mode === 'embedded') {
+    assert.deepStrictEqual(state, {applicable: false, reason: 'embedded_has_no_worker_protocol'},
+      'embedded many updates explicitly inapplicable');
+    return projection;
+  }
+  assert.equal(state.applicable, true, 'HTTP targets record many updates');
+  for (const [step, expected] of Object.entries(definition.expected)) {
+    assert.deepStrictEqual(state[step], expected, `many updates ${step}`);
+  }
+  assert.deepStrictEqual(Object.keys(state).sort(), ['applicable', ...Object.keys(definition.expected)].sort(),
+    'many updates steps');
+  return projection;
+}
diff --git a/scripts/conformance/server-parity/many-updates-probe.php b/scripts/conformance/server-parity/many-updates-probe.php
new file mode 100644
index 000000000..baa183edb
--- /dev/null
+++ b/scripts/conformance/server-parity/many-updates-probe.php
@@ -0,0 +1,144 @@
+<?php
+
+declare(strict_types=1);
+
+use DurableWorkflow\Client;
+use DurableWorkflow\Worker\CapabilityManifest;
+use GuzzleHttp\Client as ManyUpdatesHttp;
+use GuzzleHttp\HandlerStack;
+
+// A run's description after more than 64 updates, over raw worker HTTP on
+// protocol 1.20 in a fresh namespace (published Server
+// WorkflowController::show, Workflow RunWaitView and
+// StructuralLimits::pendingUpdateCountLimit). Published PHP bounds only
+// pending updates, not how many a run takes over its life. A run waiting
+// for a signal takes each update, accepted, through its own workflow task;
+// the probe records the run's description before, after the completed
+// updates, and with one more update left accepted, and the history counts.
+function finishHttpManyUpdates(Client $admin, array $fixture, string $workflowId, string $url): array
+{
+    $definition = $fixture['many_updates'];
+    $namespace = strtolower($workflowId.'-mu');
+    $admin->createNamespace($namespace, 'many updates λ', 30);
+    $token = getenv('DW_PARITY_TOKEN') ?: null;
+    $stack = HandlerStack::create();
+    $stack->push(LockPressurePollRetries::middleware(), 'lock_pressure_poll_retry');
+    $http = new ManyUpdatesHttp(['base_uri' => rtrim($url, '/').'/api/', 'http_errors' => false,
+        'connect_timeout' => 1, 'timeout' => 60, 'handler' => $stack]);
+    $headers = array_filter([
+        'Authorization' => $token === null ? null : 'Bearer '.$token,
+        'Accept' => 'application/json', 'X-Namespace' => $namespace,
+        'X-Durable-Workflow-Control-Plane-Version' => '2', 'X-Durable-Workflow-Protocol-Version' => '1.20',
+    ]);
+    $raw = static function (string $method, string $path, ?array $body = null) use ($http, $headers): array {
+        $response = $http->request($method, $path, ['headers' => $headers,
+            ...($body === null ? [] : ['json' => $body === [] ? (object) [] : $body])]);
+
+        return ['status' => $response->getStatusCode(),
+            'response' => json_decode((string) $response->getBody(), true, flags: JSON_THROW_ON_ERROR)];
+    };
+    $type = $definition['workflow_type'];
+    $update = $definition['update'];
+    $empty = ['codec' => 'avro', 'blob' => $definition['empty_blob']];
+    $id = $workflowId.'-mu';
+    $queue = $id.'-queue';
+    $worker = $id.'-worker';
+    $capabilities = ['query_tasks', 'workflow_updates'];
+    $registered = $raw('POST', 'worker/register', ['worker_id' => $worker, 'task_queue' => $queue, 'runtime' => 'php',
+        'sdk_version' => 'raw-http', 'supported_workflow_types' => [$type], 'supported_activity_types' => [],
+        'workflow_command_contracts' => [$type => ['signals' => [$definition['signal']], 'queries' => [], 'updates' => [$update], 'update_validators' => [],
+            'update_contracts' => [['name' => $update, 'parameters' => [['name' => 'value', 'required' => true, 'type' => 'array']]]]]],
+        'capabilities' => $capabilities, 'capability_manifest' => CapabilityManifest::forCapabilities($capabilities)]);
+    $started = $raw('POST', 'workflows', ['workflow_id' => $id, 'workflow_type' => $type, 'task_queue' => $queue,
+        'input' => $empty]);
+    if ($registered['status'] !== 201 || $started['status'] !== 201) {
+        throw new RuntimeException('Many updates setup: '.json_encode([$registered, $started]));
+    }
+    $poll = static function (mixed $context = null) use ($raw, $worker, $queue): array {
+        $task = $raw('POST', 'worker/workflow-tasks/poll', ['worker_id' => $worker, 'task_queue' => $queue,
+            'timeout_seconds' => 5])['response']['task'] ?? null;
+        if (! is_array($task)) {
+            throw new RuntimeException('Many updates: no workflow task was ready after '.json_encode($context));
+        }
+
+        return $task;
+    };
+    $complete = static fn (array $task, array $commands): array => $raw('POST',
+        'worker/workflow-tasks/'.$task['task_id'].'/complete', ['lease_owner' => $task['lease_owner'],
+            'workflow_task_attempt' => $task['workflow_task_attempt'], 'commands' => $commands]);
+    $describe = static fn (): array => array_intersect_key($raw('GET', 'workflows/'.rawurlencode($id))['response'],
+        array_flip($definition['described_fields']));
+    $submit = static fn (int $index): array => manyUpdatesSubmit($raw, 'workflows/'.rawurlencode($id).'/update/'.$update,
+        ['input' => [['v' => $index]], 'request_id' => 'many-'.$index, 'wait_for' => 'accepted'], $index);
+
+    $opened = $complete($poll(), [['type' => 'open_signal_wait', 'signal_name' => $definition['signal']]]);
+    $state = ['applicable' => true, 'opened' => $opened['status'], 'before' => $describe()];
+    $answers = [];
+    $lastBeat = microtime(true);
+    for ($index = 0; $index < $definition['completed_updates']; $index++) {
+        // The worker stays active across the loop, which can outlast its
+        // staleness window; a heartbeat every 20 seconds stays well inside it
+        // however slow each round trip is.
+        if (microtime(true) - $lastBeat >= 20) {
+            $beat = $raw('POST', 'worker/heartbeat', ['worker_id' => $worker]);
+            if ($beat['status'] !== 200) {
+                throw new RuntimeException('Many updates heartbeat: '.json_encode($beat));
+            }
+            $lastBeat = microtime(true);
+        }
+        $accepted = $submit($index);
+        $task = $poll([$index, $accepted]);
+        $completed = $complete($task, [['type' => 'complete_update', 'update_id' => $accepted['response']['update_id'] ?? null,
+            'result' => $empty]]);
+        $answer = implode(' ', [$accepted['status'], $accepted['response']['update_status'] ?? 'none',
+            ($task['workflow_update_id'] ?? null) === ($accepted['response']['update_id'] ?? false) ? 'own_task' : 'other_task',
+            $completed['status'], $completed['response']['run_status'] ?? 'none']);
+        $answers[$answer] = ($answers[$answer] ?? 0) + 1;
+    }
+    $state['updates'] = $answers;
+    $state['after'] = $describe();
+    $pending = $submit($definition['completed_updates']);
+    $state['pending'] = ['status' => $pending['status'], 'update_status' => $pending['response']['update_status'] ?? null,
+        'described' => $describe()];
+    $counts = [];
+    $page = $raw('GET', 'workflows/'.rawurlencode($id).'/runs/'.$started['response']['run_id'].'/history?page_size=1000')['response'];
+    foreach ($page['events'] ?? [] as $event) {
+        $counts[$event['event_type']] = ($counts[$event['event_type']] ?? 0) + 1;
+    }
+    ksort($counts);
+    $state['events'] = $counts;
+    // The accepted update's workflow task is never polled; end the run so it
+    // does not stay for the maintenance passes of later fixtures.
+    $terminated = $raw('POST', 'workflows/'.rawurlencode($id).'/terminate', ['reason' => 'many updates recorded']);
+    if (! in_array($terminated['status'], [200, 202], true)) {
+        throw new RuntimeException('Many updates cleanup: '.json_encode($terminated));
+    }
+
+    return $state;
+}
+
+/**
+ * Sends one update submission. On MySQL-family databases published PHP's
+ * update admission can deadlock against its own maintenance pass and answer
+ * an uncaught 500. The body carries a request id, so the identical
+ * submission is sent again, at most three times in all. Each retry is noted
+ * on stderr by index, attempt and status only; a third 500 is returned.
+ *
+ * @param callable(string, string, array<string, mixed>): array{status: int, response: mixed} $raw
+ * @param array<string, mixed> $body
+ * @param (callable(int): void)|null $sleep
+ * @return array{status: int, response: mixed}
+ */
+function manyUpdatesSubmit(callable $raw, string $path, array $body, int $index, ?callable $sleep = null): array
+{
+    $sleep ??= static fn (int $microseconds) => usleep($microseconds);
+    for ($attempt = 1; ; $attempt++) {
+        $answer = $raw('POST', $path, $body);
+        if ($answer['status'] !== 500 || $attempt === 3) {
+            return $answer;
+        }
+        fwrite(STDERR, json_encode(['many_updates_submit_retry' => ['index' => $index, 'attempt' => $attempt,
+            'status' => $answer['status']]], JSON_THROW_ON_ERROR).PHP_EOL);
+        $sleep(200000 * $attempt);
+    }
+}
diff --git a/scripts/conformance/server-parity/probe-capture.mjs b/scripts/conformance/server-parity/probe-capture.mjs
index 0d516e6b3..8830852fa 100644
--- a/scripts/conformance/server-parity/probe-capture.mjs
+++ b/scripts/conformance/server-parity/probe-capture.mjs
@@ -29,3 +29,12 @@ export function captureProbe(command, args, {directory, env, timeout = 45000, pr
     rmSync(capture, {recursive: true, force: true});
   }
 }
+
+// The probe diagnostics a record keeps whatever the probe's exit status:
+// only lines of these exact, value-free shapes. Other stderr is not kept.
+const NOTE_SHAPES = [/^\{"many_updates_submit_retry":\{"index":\d{1,6},"attempt":\d,"status":\d{3}\}\}$/];
+
+export function probeNotes(stderr, limit = 20) {
+  return String(stderr ?? '').split('\n').map(line => line.trim())
+    .filter(line => NOTE_SHAPES.some(shape => shape.test(line))).slice(0, limit);
+}
diff --git a/scripts/conformance/server-parity/probe.php b/scripts/conformance/server-parity/probe.php
index 4fbbaa6fc..2659a4b5c 100644
--- a/scripts/conformance/server-parity/probe.php
+++ b/scripts/conformance/server-parity/probe.php
@@ -434,6 +434,7 @@ function httpObservation(array $fixture, string $workflowId, string $namespace,
     $concurrentWaits = isset($fixture['concurrent_waits']) ? finishHttpConcurrentWaits($client, $fixture, $workflowId, $url) : null;
     $continueTransfers = isset($fixture['continue_transfers']) ? finishHttpContinueTransfers($client, $fixture, $workflowId, $url) : null;
     $largeCommandBatches = isset($fixture['large_command_batches']) ? finishHttpLargeCommandBatches($client, $fixture, $workflowId, $url) : null;
+    $manyUpdates = isset($fixture['many_updates']) ? finishHttpManyUpdates($client, $fixture, $workflowId, $url) : null;
     $startSearchAttributes = isset($fixture['start_search_attributes']) ? finishHttpStartSearchAttributes($client, $fixture, $workflowId, $url) : null;
     $queryArgumentRouting = isset($fixture['query_argument_routing']) ? finishHttpQueryArgumentRouting($client, $fixture, $workflowId, $url) : null;
     $queryContractArguments = isset($fixture['query_contract_arguments']) ? finishHttpQueryContractArguments($client, $fixture, $workflowId, $url) : null;
@@ -566,6 +567,7 @@ function httpObservation(array $fixture, string $workflowId, string $namespace,
         'concurrent_waits' => $concurrentWaits,
         'continue_transfers' => $continueTransfers,
         'large_command_batches' => $largeCommandBatches,
+        'many_updates' => $manyUpdates,
         'start_search_attributes' => $startSearchAttributes,
         'query_argument_routing' => $queryArgumentRouting,
         'query_contract_arguments' => $queryContractArguments,
@@ -901,6 +903,7 @@ function embeddedObservation(array $fixture, string $workflowId, string $namespa
     require __DIR__.'/concurrent-waits-probe.php';
     require __DIR__.'/continue-transfers-probe.php';
     require __DIR__.'/large-command-batches-probe.php';
+    require __DIR__.'/many-updates-probe.php';
     require __DIR__.'/start-search-attributes-probe.php';
     require __DIR__.'/query-arguments-probe.php';
     require __DIR__.'/query-contract-arguments-probe.php';
@@ -1096,6 +1099,9 @@ function embeddedObservation(array $fixture, string $workflowId, string $namespa
     if ($mode === 'embedded' && isset($fixture['large_command_batches'])) {
         $observation['large_command_batches'] = ['applicable' => false, 'reason' => 'embedded_has_no_worker_protocol'];
     }
+    if ($mode === 'embedded' && isset($fixture['many_updates'])) {
+        $observation['many_updates'] = ['applicable' => false, 'reason' => 'embedded_has_no_worker_protocol'];
+    }
     if ($mode === 'embedded' && isset($fixture['start_search_attributes'])) {
         $observation['start_search_attributes'] = ['applicable' => false, 'reason' => 'embedded_has_no_http_search_attribute_registry'];
     }
diff --git a/tests/Fixtures/ServerParity/many-updates.json b/tests/Fixtures/ServerParity/many-updates.json
new file mode 100644
index 000000000..4828a48a4
--- /dev/null
+++ b/tests/Fixtures/ServerParity/many-updates.json
@@ -0,0 +1,98 @@
+{
+  "schema": "durable-workflow.server-parity-fixture/v1",
+  "id": "many-updates",
+  "review_state": "reviewed",
+  "contract": "A run's description after more than 64 updates (published Server 2.11.5 WorkflowController describe with Workflow 2.15.1 RunWaitView), over raw worker HTTP on protocol 1.20 in a fresh namespace. Published PHP bounds only pending updates (DW_V2_LIMIT_PENDING_UPDATES, 500 by default), not how many a run takes over its life, and describes a run by its open waits. A run waiting for a signal takes 65 updates, each accepted and completed by its workflow task, and is still described as waiting for that signal. A 66th update left accepted is described as the run's open update. Embedded applications have no worker protocol.",
+  "workflow_type": "parity.v1.echo",
+  "input": {
+    "message": "large command batches λ",
+    "count": 9007199254740993,
+    "optional": null
+  },
+  "typed_value": {
+    "type": "map",
+    "value": {
+      "message": {
+        "type": "string",
+        "value": "large command batches λ"
+      },
+      "count": {
+        "type": "int64",
+        "value": "9007199254740993"
+      },
+      "optional": {
+        "type": "null",
+        "value": null
+      }
+    }
+  },
+  "activity": false,
+  "expected_events": [
+    "StartAccepted",
+    "WorkflowStarted",
+    "WorkflowCompleted"
+  ],
+  "many_updates": {
+    "workflow_type": "parity.v1.many_updates",
+    "update": "set",
+    "signal": "finish",
+    "completed_updates": 65,
+    "empty_blob": "wwHioz3/VYAiNwwA",
+    "described_fields": [
+      "status",
+      "status_bucket",
+      "wait_kind",
+      "wait_reason",
+      "is_terminal",
+      "resume_step_sequence",
+      "recovery_kind"
+    ],
+    "expected": {
+      "opened": 200,
+      "before": {
+        "status": "waiting",
+        "status_bucket": "running",
+        "is_terminal": false,
+        "resume_step_sequence": null,
+        "recovery_kind": null,
+        "wait_kind": "signal",
+        "wait_reason": "Waiting for signal finish"
+      },
+      "updates": {
+        "202 accepted own_task 200 waiting": 65
+      },
+      "after": {
+        "status": "waiting",
+        "status_bucket": "running",
+        "is_terminal": false,
+        "resume_step_sequence": null,
+        "recovery_kind": null,
+        "wait_kind": "signal",
+        "wait_reason": "Waiting for signal finish"
+      },
+      "pending": {
+        "status": 202,
+        "update_status": "accepted",
+        "described": {
+          "status": "waiting",
+          "status_bucket": "running",
+          "is_terminal": false,
+          "resume_step_sequence": null,
+          "recovery_kind": null,
+          "wait_kind": "update",
+          "wait_reason": "Waiting for update set"
+        }
+      },
+      "events": {
+        "MessageCursorAdvanced": 65,
+        "SignalWaitOpened": 1,
+        "StartAccepted": 1,
+        "UpdateAccepted": 66,
+        "UpdateApplied": 65,
+        "UpdateCompleted": 65,
+        "WorkflowStarted": 1
+      }
+    },
+    "overall_budget_seconds": 180
+  }
+}
diff --git a/tests/Unit/ServerParityFailureExcerptTest.mjs b/tests/Unit/ServerParityFailureExcerptTest.mjs
index 5fbe8cce1..e2a5abd07 100644
--- a/tests/Unit/ServerParityFailureExcerptTest.mjs
+++ b/tests/Unit/ServerParityFailureExcerptTest.mjs
@@ -51,3 +51,17 @@ test('stored workflow tasks are listed by counters and clocks, never payloads or
     ''].join('\n'));
   assert(!text.includes('payload-bytes') && !text.includes('error-text') && !text.includes('owner-name') && !text.includes('/not-a-request'));
 });
+
+test('labelled steps keep their request label and status, never their responses', () => {
+  const text = failureExcerpt([{fixture_id: 'signals-before-worker', outcome: 'product-fail', error: 'step statuses',
+    observation: {signals_before_worker: {steps: [
+      {request: 'POST /api/workflows', status: 201, response: {workflow_id: 'secret-run'}},
+      {request: 'POST /api/workflows/w/signal/s', status: 500, response: {message: 'Server Error', token: 'secret-token'}},
+      {request: 'not a label', status: 200}, {request: 'GET /api/x', status: '200'}]}}}]);
+  assert.equal(text, [
+    '== signals-before-worker (product-fail): step statuses',
+    'observation.signals_before_worker.steps[0] POST /api/workflows 201',
+    'observation.signals_before_worker.steps[1] POST /api/workflows/w/signal/s 500',
+    ''].join('\n'));
+  assert(!text.includes('secret-run') && !text.includes('secret-token') && !text.includes('Server Error'));
+});
diff --git a/tests/Unit/ServerParityManyUpdatesContractTest.mjs b/tests/Unit/ServerParityManyUpdatesContractTest.mjs
new file mode 100644
index 000000000..8046e3607
--- /dev/null
+++ b/tests/Unit/ServerParityManyUpdatesContractTest.mjs
@@ -0,0 +1,40 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import {readFileSync} from 'node:fs';
+import {checkManyUpdates} from '../../scripts/conformance/server-parity/many-updates-contract.mjs';
+
+const fixture = JSON.parse(readFileSync(new URL('../Fixtures/ServerParity/many-updates.json', import.meta.url), 'utf8'));
+const expected = fixture.many_updates.expected;
+const observation = () => structuredClone({mode: 'http', many_updates: {applicable: true, ...expected}});
+const steps = Object.keys(expected).length;
+
+test('the published answers pass', () => {
+  assert.deepStrictEqual(checkManyUpdates(fixture, observation()), {scope: 'many_updates', steps});
+});
+
+test('embedded applications have no worker protocol', () => {
+  assert.deepStrictEqual(checkManyUpdates(fixture,
+    {mode: 'embedded', many_updates: {applicable: false, reason: 'embedded_has_no_worker_protocol'}}),
+  {scope: 'many_updates', steps});
+  assert.throws(() => checkManyUpdates(fixture, {mode: 'embedded', many_updates: {applicable: true}}));
+});
+
+test('65 completed updates leave the signal wait, and a 66th is the open update', () => {
+  assert.deepStrictEqual(expected.updates, {'202 accepted own_task 200 waiting': 65});
+  assert.deepStrictEqual([expected.after.wait_kind, expected.pending.described.wait_kind], ['signal', 'update']);
+  assert.deepStrictEqual([expected.events.UpdateAccepted, expected.events.UpdateCompleted], [66, 65]);
+});
+
+for (const [name, mutate] of [
+  ['a run described without its wait after 64 updates', state => {
+    state.after.wait_kind = null; state.after.wait_reason = null;
+  }],
+  ['a pending update that is not the open wait', state => { state.pending.described.wait_kind = 'signal'; }],
+  ['a refused 65th update', state => {
+    state.updates = {'202 accepted own_task 200 waiting': 64, '503 none other_task 404 none': 1};
+  }],
+  ['an unexpected step', state => { state.extra = {}; }],
+]) test(`the contract rejects ${name}`, () => {
+  const raw = observation(); mutate(raw.many_updates);
+  assert.throws(() => checkManyUpdates(fixture, raw));
+});
diff --git a/tests/Unit/ServerParityManyUpdatesRetryTest.php b/tests/Unit/ServerParityManyUpdatesRetryTest.php
new file mode 100644
index 000000000..b26da6881
--- /dev/null
+++ b/tests/Unit/ServerParityManyUpdatesRetryTest.php
@@ -0,0 +1,64 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit;
+
+use PHPUnit\Framework\TestCase;
+
+require_once dirname(__DIR__, 2).'/scripts/conformance/server-parity/many-updates-probe.php';
+
+final class ServerParityManyUpdatesRetryTest extends TestCase
+{
+    private const BODY = ['input' => [['v' => 7]], 'request_id' => 'many-7', 'wait_for' => 'accepted'];
+
+    /**
+     * Sends with answers in order; returns the answer and every request sent.
+     *
+     * @param list<int> $statuses
+     * @return array{0: array{status: int, response: mixed}, 1: list<array{0: string, 1: string, 2: array<string, mixed>}>, 2: list<int>}
+     */
+    private function submit(array $statuses): array
+    {
+        $sent = [];
+        $slept = [];
+        $raw = function (string $method, string $path, array $body) use (&$sent, &$statuses): array {
+            $sent[] = [$method, $path, $body];
+
+            return ['status' => array_shift($statuses), 'response' => ['message' => 'Server Error']];
+        };
+        $answer = \manyUpdatesSubmit($raw, 'workflows/w/update/set', self::BODY, 7,
+            function (int $microseconds) use (&$slept): void {
+                $slept[] = $microseconds;
+            });
+
+        return [$answer, $sent, $slept];
+    }
+
+    public function test_a_500_is_sent_again_with_the_same_request_id(): void
+    {
+        [$answer, $sent, $slept] = $this->submit([500, 500, 202]);
+
+        self::assertSame(202, $answer['status']);
+        self::assertCount(3, $sent);
+        foreach ($sent as $request) {
+            self::assertSame(['POST', 'workflows/w/update/set', self::BODY], $request);
+        }
+        self::assertSame([200000, 400000], $slept);
+    }
+
+    public function test_other_statuses_return_at_once(): void
+    {
+        foreach ([202, 409, 422, 503] as $status) {
+            [$answer, $sent, $slept] = $this->submit([$status, 202]);
+            self::assertSame([$status, 1, []], [$answer['status'], count($sent), $slept], "status {$status}");
+        }
+    }
+
+    public function test_a_third_500_is_returned(): void
+    {
+        [$answer, $sent] = $this->submit([500, 500, 500, 202]);
+
+        self::assertSame([500, 3], [$answer['status'], count($sent)]);
+    }
+}
diff --git a/tests/Unit/ServerParityProbeNotesTest.mjs b/tests/Unit/ServerParityProbeNotesTest.mjs
new file mode 100644
index 000000000..fc8139a49
--- /dev/null
+++ b/tests/Unit/ServerParityProbeNotesTest.mjs
@@ -0,0 +1,41 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import {spawnSync} from 'node:child_process';
+import {chmodSync, mkdtempSync, readFileSync, rmSync, writeFileSync} from 'node:fs';
+import {tmpdir} from 'node:os';
+import {delimiter, join} from 'node:path';
+import {fileURLToPath} from 'node:url';
+import {probeNotes} from '../../scripts/conformance/server-parity/probe-capture.mjs';
+
+const runner = fileURLToPath(new URL('../../scripts/conformance/server-parity.mjs', import.meta.url));
+const fixture = fileURLToPath(new URL('../Fixtures/ServerParity/many-updates.json', import.meta.url));
+const note = '{"many_updates_submit_retry":{"index":15,"attempt":1,"status":500}}';
+
+test('only the recognized value-free notes are kept', () => {
+  assert.deepStrictEqual(probeNotes(`noise\n${note}\n{"many_updates_submit_retry":{"index":1,"attempt":1,"status":500,"body":"x"}}\n` +
+    `{"other":1}\n  ${note}  \n`), [note, note]);
+  assert.deepStrictEqual(probeNotes(Array(30).fill(note).join('\n')).length, 20);
+  assert.deepStrictEqual(probeNotes(undefined), []);
+});
+
+// A probe that exits 0 after a recovered retry: the recorder keeps its note
+// on the case and in its own stderr, and nothing else from the probe's.
+test('a successful probe keeps its retry note in the record and the recorder log', () => {
+  const directory = mkdtempSync(join(tmpdir(), 'dw-probe-notes-'));
+  try {
+    writeFileSync(join(directory, 'php'),
+      `#!/bin/sh\necho '${note}' >&2\necho 'private stderr text' >&2\necho '{"mode":"http"}'\nexit 0\n`);
+    chmodSync(join(directory, 'php'), 0o755);
+    const output = join(directory, 'php-record.json');
+    const run = spawnSync(process.execPath, [runner, 'record', '--mode', 'http', '--url', 'http://127.0.0.1:9',
+      '--target', 'php', '--output', output, '--runner-revision', '0'.repeat(40), '--fixture', fixture],
+    {encoding: 'utf8', env: {...process.env, PATH: `${directory}${delimiter}${process.env.PATH}`}});
+    assert.ok(run.stderr.includes(`many-updates: ${note}`), `recorder stderr keeps the note:\n${run.stderr}`);
+    assert.doesNotMatch(run.stderr, /private stderr text/);
+    const record = JSON.parse(readFileSync(output, 'utf8'));
+    assert.deepStrictEqual(record.cases[0].probe_notes, [note]);
+    assert.doesNotMatch(readFileSync(output, 'utf8'), /private stderr text/);
+  } finally {
+    rmSync(directory, {recursive: true, force: true});
+  }
+});
diff --git a/tests/Unit/Support/composer-sinks.json b/tests/Unit/Support/composer-sinks.json
index 2207dfa5d..77e1d92c4 100644
--- a/tests/Unit/Support/composer-sinks.json
+++ b/tests/Unit/Support/composer-sinks.json
@@ -19,7 +19,7 @@
     },
     {
       "path": ".github/workflows/phpunit-feature.yml",
-      "line": "-lc 'set -eu; tar --no-same-owner -xf - -C /app; cp -a /app/workflow-package /workflow; php scripts/ci/prepare-release-workflow-composer-metadata.php; composer update durable-workflow/workflow --with-dependencies --minimal-changes --no-install --no-scripts --no-autoloader --no-interaction --no-progress --prefer-dist; composer install --no-interaction --no-progress --prefer-dist; git --version; vendor/bin/phpunit --version; git rev-parse --verify \"$CORPUS_BASE_REF^{commit}\"; php scripts/ci/check-worker-openapi-evolution.php \"$CORPUS_BASE_REF\"; vendor/bin/phpunit tests/Feature tests/Unit/NexusContractTest.php tests/Unit/CodecRegressionCorpusTest.php tests/Unit/PhpunitFeatureWorkflowContractTest.php tests/Unit/OpenApiDocumentEvolutionTest.php tests/Unit/NamespaceConformanceRunnerContractTest.php tests/Unit/NamespaceRuntimeContractTest.php tests/Unit/SchedulesConformanceRunnerContractTest.php tests/Unit/SchedulesRuntimeContractTest.php tests/Unit/ServerParitySdkDirectionResponseSummaryTest.php tests/Unit/ServerParitySdkQueryTransportTest.php tests/Unit/ServerParitySdkUpdateTransportTest.php tests/Unit/ServerParityLockPressureRetryTest.php --no-progress --colors=never; vendor/bin/phpunit tests/Unit/ReleaseImageImmutabilityGuardTest.php --no-progress --colors=never; vendor/bin/phpunit tests/Unit/ReleaseImagePublishWorkflowContractTest.php --filter test_php_security_audits_fail_before_release_publication --no-progress --colors=never; python3 scripts/ci/validate-regression-corpus.py --base-ref \"$CORPUS_BASE_REF\" --verify-counterfactual'",
+      "line": "-lc 'set -eu; tar --no-same-owner -xf - -C /app; cp -a /app/workflow-package /workflow; php scripts/ci/prepare-release-workflow-composer-metadata.php; composer update durable-workflow/workflow --with-dependencies --minimal-changes --no-install --no-scripts --no-autoloader --no-interaction --no-progress --prefer-dist; composer install --no-interaction --no-progress --prefer-dist; git --version; vendor/bin/phpunit --version; git rev-parse --verify \"$CORPUS_BASE_REF^{commit}\"; php scripts/ci/check-worker-openapi-evolution.php \"$CORPUS_BASE_REF\"; vendor/bin/phpunit tests/Feature tests/Unit/NexusContractTest.php tests/Unit/CodecRegressionCorpusTest.php tests/Unit/PhpunitFeatureWorkflowContractTest.php tests/Unit/OpenApiDocumentEvolutionTest.php tests/Unit/NamespaceConformanceRunnerContractTest.php tests/Unit/NamespaceRuntimeContractTest.php tests/Unit/SchedulesConformanceRunnerContractTest.php tests/Unit/SchedulesRuntimeContractTest.php tests/Unit/ServerParitySdkDirectionResponseSummaryTest.php tests/Unit/ServerParitySdkQueryTransportTest.php tests/Unit/ServerParitySdkUpdateTransportTest.php tests/Unit/ServerParityLockPressureRetryTest.php tests/Unit/ServerParityManyUpdatesRetryTest.php --no-progress --colors=never; vendor/bin/phpunit tests/Unit/ReleaseImageImmutabilityGuardTest.php --no-progress --colors=never; vendor/bin/phpunit tests/Unit/ReleaseImagePublishWorkflowContractTest.php --filter test_php_security_audits_fail_before_release_publication --no-progress --colors=never; python3 scripts/ci/validate-regression-corpus.py --base-ref \"$CORPUS_BASE_REF\" --verify-counterfactual'",
       "count": 2,
       "confinement": "Runs in the source-free corpus tool image. The feature step checks its system bundle, hashed directory and Composer selection before fresh source and dependency installation, on cold builds and cache hits.",
       "guards": [