diff --git a/temporalio/rbi/temporalio/workflow/future.rbi b/temporalio/rbi/temporalio/workflow/future.rbi
index e9f96348..875724dc 100644
--- a/temporalio/rbi/temporalio/workflow/future.rbi
+++ b/temporalio/rbi/temporalio/workflow/future.rbi
@@ -13,7 +13,7 @@ class Temporalio::Workflow::Future
   attr_reader :failure
 
   sig { params(block: T.nilable(T.proc.returns(Elem))).void }
-  def initialize(&); end
+  def initialize(&block); end
 
   sig { returns(T::Boolean) }
   def done?; end
diff --git a/temporalio/test/sig/support/sig_applicator.rbs b/temporalio/test/sig/support/sig_applicator.rbs
index 8eeac6b2..aca37401 100644
--- a/temporalio/test/sig/support/sig_applicator.rbs
+++ b/temporalio/test/sig/support/sig_applicator.rbs
@@ -46,6 +46,7 @@ module SigApplicator
   def self.register_summary_hook!: -> void
   def self.raise_recorded_type_errors!: -> void
   def self.raise_instrumentation_errors!: (Accumulator acc) -> void
+  def self.valid_rbi_signatures?: (untyped node, Accumulator acc) -> bool
   def self.apply_scope: (untyped node, Accumulator acc) -> void
   def self.apply_method_sig: (
     Module target,
diff --git a/temporalio/test/support/sig_applicator.rb b/temporalio/test/support/sig_applicator.rb
index f3274aab..1808f664 100644
--- a/temporalio/test/support/sig_applicator.rb
+++ b/temporalio/test/support/sig_applicator.rb
@@ -116,6 +116,8 @@ def apply_all!
 
       rbi_paths.each do |path|
         tree = RBI::Parser.parse_file(path)
+        next unless valid_rbi_signatures?(tree, acc)
+
         tree.nodes.each do |node|
           apply_scope(node, acc)
         end
@@ -209,6 +211,33 @@ def raise_instrumentation_errors!(acc)
       raise summary.chomp
     end
 
+    def valid_rbi_signatures?(node, acc)
+      valid = true
+
+      if node.is_a?(RBI::Method)
+        method_param_names = node.params.map(&:name).sort
+        node.sigs.each do |sig|
+          sig_param_names = sig.params.map(&:name).sort
+          next if sig_param_names == method_param_names
+
+          valid = false
+          method_name = node.fully_qualified_name.delete_prefix('::')
+          method_name = method_name.sub(/::([^:]+)\z/, '.\1') if node.is_singleton
+          method_name = method_name.sub('::<self>#', '.')
+          acc.error "#{method_name}: signature parameters #{sig_param_names.inspect} " \
+                    "do not match method parameters #{method_param_names.inspect}"
+        end
+      end
+
+      if node.respond_to?(:nodes)
+        node.nodes.each do |child|
+          valid = false unless valid_rbi_signatures?(child, acc)
+        end
+      end
+
+      valid
+    end
+
     def apply_scope(node, acc)
       return unless node.respond_to?(:nodes)
 
diff --git a/temporalio/test/support/sig_applicator_test.rb b/temporalio/test/support/sig_applicator_test.rb
index 93e3bbb9..0cb6781f 100644
--- a/temporalio/test/support/sig_applicator_test.rb
+++ b/temporalio/test/support/sig_applicator_test.rb
@@ -237,6 +237,29 @@ def self.foo(value); end
       end
     end
 
+    def test_apply_all_rejects_mismatched_params_in_skipped_class
+      tree = RBI::Parser.parse_string(<<~RBI)
+        class Temporalio::Workflow::Future
+          sig { params(block: T.nilable(T.proc.void)).void }
+          def initialize(&); end
+        end
+      RBI
+
+      parser = RBI::Parser.singleton_class
+      original_parse_file = RBI::Parser.method(:parse_file)
+      parser.send(:define_method, :parse_file) { |_path| tree }
+
+      error = assert_raises(RuntimeError) do
+        with_sig_applicator_rbi_paths(['test.rbi']) { SigApplicator.apply_all! }
+      end
+      assert_includes error.message, 'SigApplicator: 1 methods could not be instrumented:'
+      assert_includes error.message,
+                      'Temporalio::Workflow::Future#initialize: signature parameters ["block"] ' \
+                      'do not match method parameters ["&block"]'
+    ensure
+      parser.send(:define_method, :parse_file, original_parse_file)
+    end
+
     def test_apply_all_reads_all_rbi_paths
       test_class = Class.new do
         def self.foo(value)