Handle longer Markdown fence closers

Author: justin808

.agents/bin/agent-workflow-seam-doctor

@@ -211,13 +211,17 @@ module AgentWorkflowSeamDoctor
 
     delimiter = fence[1]
     # Mismatched closers stay inside the current fence.
-    return nil if in_fence && delimiter != fence_delimiter
+    return nil if in_fence && !closing_fence_delimiter?(delimiter, fence_delimiter)
     return [false, false, nil] if in_fence
 
     language = fence[2].to_s.downcase
     [true, EXECUTABLE_FENCE_LANGS.include?(language), delimiter]
   end
 
+  def closing_fence_delimiter?(delimiter, fence_delimiter)
+    delimiter[0] == fence_delimiter[0] && delimiter.length >= fence_delimiter.length
+  end
+
   def placeholders_from_line(line, in_fence:, executable_fence:)
     placeholders = []
 

.agents/bin/agent-workflow-seam-doctor-test.rb

@@ -350,6 +350,22 @@ def test_shorter_closing_fence_does_not_close_long_executable_fence
     end
   end
 
+  def test_longer_closing_fence_closes_long_executable_fence
+    with_repo do |root|
+      write_agents(root)
+      write_skill(root, <<~MARKDOWN)
+        ````bash
+        echo ok
+        `````
+        <follow-up prefix>
+      MARKDOWN
+
+      out, status = run_doctor(root)
+
+      assert status.success?, out
+    end
+  end
+
   def test_four_space_indented_fence_does_not_open_executable_fence
     with_repo do |root|
       write_agents(root)