diff --git a/source/fuzz/fact_manager.cpp b/source/fuzz/fact_manager.cpp
index 9cb6896..442ff16 100644
--- a/source/fuzz/fact_manager.cpp
+++ b/source/fuzz/fact_manager.cpp
@@ -14,12 +14,60 @@
 
 #include "source/fuzz/fact_manager.h"
 
+#include <sstream>
+
 #include "source/fuzz/uniform_buffer_element_descriptor.h"
 #include "source/opt/ir_context.h"
 
 namespace spvtools {
 namespace fuzz {
 
+namespace {
+
+std::string ToString(const protobufs::Fact& fact) {
+  assert(fact.fact_case() == protobufs::Fact::kConstantUniformFact &&
+         "Right now this is the only fact.");
+  std::stringstream stream;
+  stream << "("
+         << fact.constant_uniform_fact()
+                .uniform_buffer_element_descriptor()
+                .descriptor_set()
+         << ", "
+         << fact.constant_uniform_fact()
+                .uniform_buffer_element_descriptor()
+                .binding()
+         << ")[";
+
+  bool first = true;
+  for (auto index : fact.constant_uniform_fact()
+                        .uniform_buffer_element_descriptor()
+                        .index()) {
+    if (first) {
+      first = false;
+    } else {
+      stream << ", ";
+    }
+    stream << index;
+  }
+
+  stream << "] == [";
+
+  first = true;
+  for (auto constant_word : fact.constant_uniform_fact().constant_word()) {
+    if (first) {
+      first = false;
+    } else {
+      stream << ", ";
+    }
+    stream << constant_word;
+  }
+
+  stream << "]";
+  return stream.str();
+}
+
+}  // namespace
+
 // The purpose of this struct is to group the fields and data used to represent
 // facts about uniform constants.
 struct FactManager::ConstantUniformFacts {
@@ -288,16 +336,16 @@
 
 FactManager::~FactManager() = default;
 
-bool FactManager::AddFacts(const protobufs::FactSequence& initial_facts,
+void FactManager::AddFacts(const MessageConsumer& message_consumer,
+                           const protobufs::FactSequence& initial_facts,
                            opt::IRContext* context) {
   for (auto& fact : initial_facts.fact()) {
     if (!AddFact(fact, context)) {
-      // TODO(https://github.com/KhronosGroup/SPIRV-Tools/issues/2621) Provide
-      //  information about the fact that could not be added.
-      return false;
+      message_consumer(
+          SPV_MSG_WARNING, nullptr, {},
+          ("Invalid fact " + ToString(fact) + " ignored.").c_str());
     }
   }
-  return true;
 }
 
 bool FactManager::AddFact(const spvtools::fuzz::protobufs::Fact& fact,
diff --git a/source/fuzz/fact_manager.h b/source/fuzz/fact_manager.h
index 2eee9ab..cb4ac58 100644
--- a/source/fuzz/fact_manager.h
+++ b/source/fuzz/fact_manager.h
@@ -41,11 +41,14 @@
   ~FactManager();
 
   // Adds all the facts from |facts|, checking them for validity with respect to
-  // |context|. Returns true if and only if all facts are valid.
-  bool AddFacts(const protobufs::FactSequence& facts, opt::IRContext* context);
+  // |context|.  Warnings about invalid facts are communicated via
+  // |message_consumer|; such facts are otherwise ignored.
+  void AddFacts(const MessageConsumer& message_consumer,
+                const protobufs::FactSequence& facts, opt::IRContext* context);
 
-  // Adds |fact| to the fact manager, checking it for validity with respect to
-  // |context|. Returns true if and only if the fact is valid.
+  // Checks the fact for validity with respect to |context|.  Returns false,
+  // with no side effects, if the fact is invalid.  Otherwise adds |fact| to the
+  // fact manager.
   bool AddFact(const protobufs::Fact& fact, opt::IRContext* context);
 
   // The fact manager will ultimately be responsible for managing a few distinct
diff --git a/source/fuzz/fuzzer.cpp b/source/fuzz/fuzzer.cpp
index 42033e2..606ccd6 100644
--- a/source/fuzz/fuzzer.cpp
+++ b/source/fuzz/fuzzer.cpp
@@ -97,9 +97,7 @@
   FuzzerContext fuzzer_context(&random_generator, minimum_fresh_id);
 
   FactManager fact_manager;
-  if (!fact_manager.AddFacts(initial_facts, ir_context.get())) {
-    return Fuzzer::FuzzerResultStatus::kInitialFactsInvalid;
-  }
+  fact_manager.AddFacts(impl_->consumer, initial_facts, ir_context.get());
 
   // Add some essential ingredients to the module if they are not already
   // present, such as boolean constants.
diff --git a/source/fuzz/fuzzer.h b/source/fuzz/fuzzer.h
index f81f297..af45d9b 100644
--- a/source/fuzz/fuzzer.h
+++ b/source/fuzz/fuzzer.h
@@ -33,7 +33,6 @@
     kComplete,
     kFailedToCreateSpirvToolsInterface,
     kInitialBinaryInvalid,
-    kInitialFactsInvalid,
   };
 
   // Constructs a fuzzer from the given target environment.
diff --git a/source/fuzz/replayer.cpp b/source/fuzz/replayer.cpp
index 951b2a5..b0d4ee2 100644
--- a/source/fuzz/replayer.cpp
+++ b/source/fuzz/replayer.cpp
@@ -81,9 +81,7 @@
   assert(ir_context);
 
   FactManager fact_manager;
-  if (!fact_manager.AddFacts(initial_facts, ir_context.get())) {
-    return Replayer::ReplayerResultStatus::kInitialFactsInvalid;
-  }
+  fact_manager.AddFacts(impl_->consumer, initial_facts, ir_context.get());
 
   // Consider the transformation proto messages in turn.
   for (auto& message : transformation_sequence_in.transformation()) {
diff --git a/source/fuzz/replayer.h b/source/fuzz/replayer.h
index a45cbb4..13391d0 100644
--- a/source/fuzz/replayer.h
+++ b/source/fuzz/replayer.h
@@ -33,7 +33,6 @@
     kComplete,
     kFailedToCreateSpirvToolsInterface,
     kInitialBinaryInvalid,
-    kInitialFactsInvalid,
   };
 
   // Constructs a replayer from the given target environment.
diff --git a/tools/fuzz/fuzz.cpp b/tools/fuzz/fuzz.cpp
index 9943dff..8967b4a 100644
--- a/tools/fuzz/fuzz.cpp
+++ b/tools/fuzz/fuzz.cpp
@@ -257,7 +257,7 @@
   const std::string dot_spv(".spv");
   std::string in_facts_file =
       in_binary_file.substr(0, in_binary_file.length() - dot_spv.length()) +
-      ".json";
+      ".facts";
   std::ifstream facts_input(in_facts_file);
   if (facts_input) {
     std::string facts_json_string((std::istreambuf_iterator<char>(facts_input)),