diff --git a/bosk-core/src/main/java/io/vena/bosk/Bosk.java b/bosk-core/src/main/java/io/vena/bosk/Bosk.java
index 4d80d2ac..2b2e6b8a 100644
--- a/bosk-core/src/main/java/io/vena/bosk/Bosk.java
+++ b/bosk-core/src/main/java/io/vena/bosk/Bosk.java
@@ -1,5 +1,7 @@
 package io.vena.bosk;
 
+import io.opentelemetry.instrumentation.annotations.SpanAttribute;
+import io.opentelemetry.instrumentation.annotations.WithSpan;
 import io.vena.bosk.BoskDiagnosticContext.DiagnosticScope;
 import io.vena.bosk.ReferenceUtils.CatalogRef;
 import io.vena.bosk.ReferenceUtils.ListingRef;
@@ -399,7 +401,7 @@ private <T,S> void triggerQueueingOfHooks(Reference<T> target, @Nullable R prior
 					) {
 						try (@SuppressWarnings("unused") ReadContext executionContext = new ReadContext(rootForHook)) {
 							LOGGER.debug("Hook: RUN {}({})", reg.name, changedRef);
-							reg.hook.onChanged(changedRef);
+							callHook(reg, changedRef, reg.name());
 						} catch (Exception e) {
 							LOGGER.error("Bosk hook \"" + reg.name() + "\" terminated with an exception, which usually indicates a bug. State updates may have been lost", e);
 
@@ -415,6 +417,11 @@ private <T,S> void triggerQueueingOfHooks(Reference<T> target, @Nullable R prior
 			});
 		}
 
+		@WithSpan
+		private static <R extends StateTreeNode, S> void callHook(Bosk<R>.HookRegistration<S> reg, @SpanAttribute("hook.reference") Reference<S> changedRef, @SpanAttribute("hook.name") String hookName) {
+			reg.hook.onChanged(changedRef);
+		}
+
 		/**
 		 * Runs queued hooks in a "breadth-first" fashion: all hooks "H" triggered by
 		 * any single hook "G" will run before any consequent hooks triggered by "H".
diff --git a/bosk-core/src/main/java/io/vena/bosk/drivers/OtelSpanContextDriver.java b/bosk-core/src/main/java/io/vena/bosk/drivers/OtelSpanContextDriver.java
index f3f6c03f..79597a5d 100644
--- a/bosk-core/src/main/java/io/vena/bosk/drivers/OtelSpanContextDriver.java
+++ b/bosk-core/src/main/java/io/vena/bosk/drivers/OtelSpanContextDriver.java
@@ -1,6 +1,9 @@
 package io.vena.bosk.drivers;
 
+import io.opentelemetry.api.trace.Span;
 import io.opentelemetry.api.trace.SpanContext;
+import io.opentelemetry.instrumentation.annotations.SpanAttribute;
+import io.opentelemetry.instrumentation.annotations.WithSpan;
 import io.vena.bosk.BoskDiagnosticContext;
 import io.vena.bosk.BoskDriver;
 import io.vena.bosk.DriverFactory;
@@ -18,60 +21,100 @@
 public class OtelSpanContextDriver<R extends StateTreeNode> implements BoskDriver<R> {
 	private final BoskDiagnosticContext context;
 	private final BoskDriver<R> downstream;
+	private final String caller;
 
-	OtelSpanContextDriver(BoskDiagnosticContext context, BoskDriver<R> downstream) {
+	OtelSpanContextDriver(BoskDiagnosticContext context, BoskDriver<R> downstream, String caller) {
 		this.context = context;
 		this.downstream = downstream;
+		this.caller = caller;
 	}
 
 	public static <RR extends StateTreeNode> DriverFactory<RR> factory() {
-		return (b,d) -> new OtelSpanContextDriver<>(b.rootReference().diagnosticContext(), d);
+		StackTraceElement caller = new RuntimeException().getStackTrace()[1];
+		return (b,d) -> new OtelSpanContextDriver<>(
+			b.rootReference().diagnosticContext(),
+			d,
+			caller.toString()
+		);
 	}
 
 	@Override
-	public R initialRoot(Type rootType) throws InvalidTypeException, IOException, InterruptedException {
+	@WithSpan("initialRoot")
+	public R initialRoot(
+		@SpanAttribute("bosk.rootType") Type rootType
+	) throws InvalidTypeException, IOException, InterruptedException {
+		Span.current().setAttribute("bosk.createdAt", caller);
 		try (var __ = context.withCurrentOtelContext()) {
 			return downstream.initialRoot(rootType);
 		}
 	}
 
 	@Override
-	public <T> void submitReplacement(Reference<T> target, T newValue) {
+	@WithSpan("submitReplacement")
+	public <T> void submitReplacement(
+		@SpanAttribute("bosk.target") Reference<T> target,
+		T newValue
+	) {
+		Span.current().setAttribute("bosk.createdAt", caller);
 		try (var __ = context.withCurrentOtelContext()) {
 			downstream.submitReplacement(target, newValue);
 		}
 	}
 
 	@Override
-	public <T> void submitConditionalReplacement(Reference<T> target, T newValue, Reference<Identifier> precondition, Identifier requiredValue) {
+	@WithSpan("submitConditionalReplacement")
+	public <T> void submitConditionalReplacement(
+		@SpanAttribute("bosk.target") Reference<T> target,
+		T newValue,
+		@SpanAttribute("bosk.precondition") Reference<Identifier> precondition,
+		@SpanAttribute("bosk.requiredValue") Identifier requiredValue
+	) {
+		Span.current().setAttribute("bosk.createdAt", caller);
 		try (var __ = context.withCurrentOtelContext()) {
 			downstream.submitConditionalReplacement(target, newValue, precondition, requiredValue);
 		}
 	}
 
 	@Override
-	public <T> void submitInitialization(Reference<T> target, T newValue) {
+	@WithSpan("submitInitialization")
+	public <T> void submitInitialization(
+		@SpanAttribute("bosk.target") Reference<T> target,
+		T newValue
+	) {
+		Span.current().setAttribute("bosk.createdAt", caller);
 		try (var __ = context.withCurrentOtelContext()) {
 			downstream.submitInitialization(target, newValue);
 		}
 	}
 
 	@Override
-	public <T> void submitDeletion(Reference<T> target) {
+	@WithSpan("submitDeletion")
+	public <T> void submitDeletion(
+		@SpanAttribute("bosk.target") Reference<T> target
+	) {
+		Span.current().setAttribute("bosk.createdAt", caller);
 		try (var __ = context.withCurrentOtelContext()) {
 			downstream.submitDeletion(target);
 		}
 	}
 
 	@Override
-	public <T> void submitConditionalDeletion(Reference<T> target, Reference<Identifier> precondition, Identifier requiredValue) {
+	@WithSpan("submitConditionalDeletion")
+	public <T> void submitConditionalDeletion(
+		@SpanAttribute("bosk.target") Reference<T> target,
+		@SpanAttribute("bosk.precondition") Reference<Identifier> precondition,
+		@SpanAttribute("bosk.requiredValue") Identifier requiredValue
+	) {
+		Span.current().setAttribute("bosk.createdAt", caller);
 		try (var __ = context.withCurrentOtelContext()) {
 			downstream.submitConditionalDeletion(target, precondition, requiredValue);
 		}
 	}
 
 	@Override
+	@WithSpan("InterruptedException")
 	public void flush() throws IOException, InterruptedException {
+		Span.current().setAttribute("bosk.createdAt", caller);
 		try (var __ = context.withCurrentOtelContext()) {
 			downstream.flush();
 		}
diff --git a/bosk-mongo/src/main/java/io/vena/bosk/drivers/mongo/MainDriver.java b/bosk-mongo/src/main/java/io/vena/bosk/drivers/mongo/MainDriver.java
index 5dbd29e7..0f6cdaf5 100644
--- a/bosk-mongo/src/main/java/io/vena/bosk/drivers/mongo/MainDriver.java
+++ b/bosk-mongo/src/main/java/io/vena/bosk/drivers/mongo/MainDriver.java
@@ -375,6 +375,7 @@ private Listener(FutureTask<R> initialRootAction) {
 		}
 
 		@Override
+		@WithSpan("onConnectionSucceeded")
 		public void onConnectionSucceeded() throws
 			UnrecognizedFormatException,
 			UninitializedCollectionException,
@@ -582,7 +583,6 @@ private MDCScope beginDriverOperation(String description, Object... args) {
 		return ex;
 	}
 
-	@WithSpan
 	private <X extends Exception, Y extends Exception> void doRetryableDriverOperation(RetryableOperation<X,Y> operation, String description, Object... args) throws X,Y {
 		RetryableOperation<X,Y> operationInSession = () -> {
 			int immediateRetriesLeft = 2;
diff --git a/bosk-mongo/src/test/java/io/vena/bosk/drivers/mongo/MongoDriverHanoiTest.java b/bosk-mongo/src/test/java/io/vena/bosk/drivers/mongo/MongoDriverHanoiTest.java
index 9736fd56..ae7d5349 100644
--- a/bosk-mongo/src/test/java/io/vena/bosk/drivers/mongo/MongoDriverHanoiTest.java
+++ b/bosk-mongo/src/test/java/io/vena/bosk/drivers/mongo/MongoDriverHanoiTest.java
@@ -27,7 +27,8 @@ public MongoDriverHanoiTest(ParameterSet parameters) {
 				mongoService.clientSettings(),
 				settings,
 				new BsonPlugin()
-			)
+			),
+			OtelSpanContextDriver.factory()
 		);
 		mongoService.client()
 			.getDatabase(settings.database())
diff --git a/bosk-testing/src/main/java/io/vena/bosk/drivers/AbstractDriverTest.java b/bosk-testing/src/main/java/io/vena/bosk/drivers/AbstractDriverTest.java
index 2385efcb..3493d34d 100644
--- a/bosk-testing/src/main/java/io/vena/bosk/drivers/AbstractDriverTest.java
+++ b/bosk-testing/src/main/java/io/vena/bosk/drivers/AbstractDriverTest.java
@@ -53,6 +53,7 @@ protected void setupBosksAndReferences(DriverFactory<TestEntity> driverFactory)
 		// This is the bosk we're testing
 		bosk = new Bosk<TestEntity>("Test bosk", TestEntity.class, AbstractDriverTest::initialRoot, DriverStack.of(
 			MirroringDriver.targeting(canonicalBosk),
+			OtelSpanContextDriver.factory(),
 			DriverStateVerifier.wrap(driverFactory, TestEntity.class, AbstractDriverTest::initialRoot)
 		));
 		driver = bosk.driver();
diff --git a/bosk-testing/src/main/java/io/vena/bosk/drivers/DriverConformanceTest.java b/bosk-testing/src/main/java/io/vena/bosk/drivers/DriverConformanceTest.java
index f4eed1f5..299afc45 100644
--- a/bosk-testing/src/main/java/io/vena/bosk/drivers/DriverConformanceTest.java
+++ b/bosk-testing/src/main/java/io/vena/bosk/drivers/DriverConformanceTest.java
@@ -1,5 +1,7 @@
 package io.vena.bosk.drivers;
 
+import io.opentelemetry.instrumentation.annotations.SpanAttribute;
+import io.opentelemetry.instrumentation.annotations.WithSpan;
 import io.vena.bosk.Bosk;
 import io.vena.bosk.Catalog;
 import io.vena.bosk.CatalogReference;
@@ -62,7 +64,8 @@ void initialState(Path enclosingCatalogPath) {
 	}
 
 	@ParametersByName
-	void replaceIdentical(Path enclosingCatalogPath, Identifier childID) throws InvalidTypeException {
+	@WithSpan("replaceIdentical")
+	void replaceIdentical(@SpanAttribute("enclosingPath") Path enclosingCatalogPath, @SpanAttribute("childID") Identifier childID) throws InvalidTypeException {
 		CatalogReference<TestEntity> ref = initializeBoskWithCatalog(enclosingCatalogPath);
 		driver.submitReplacement(ref.then(childID), newEntity(childID, ref));
 		assertCorrectBoskContents();
@@ -455,7 +458,8 @@ private Reference<TestValues> initializeBoskWithBlankValues(Path enclosingCatalo
 		return ref;
 	}
 
-	private CatalogReference<TestEntity> initializeBoskWithCatalog(Path enclosingCatalogPath) {
+	@WithSpan
+	private CatalogReference<TestEntity> initializeBoskWithCatalog(@SpanAttribute("enclosingCatalogPath") Path enclosingCatalogPath) {
 		LOGGER.debug("initializeBoskWithCatalog({})", enclosingCatalogPath);
 		setupBosksAndReferences(driverFactory);
 		try {