diff --git a/spec/ruby_llm/models_gpt_5_6_bedrock_spec.rb b/spec/ruby_llm/models_gpt_5_6_bedrock_spec.rb
index 955ef87f8..ab326ae0c 100644
--- a/spec/ruby_llm/models_gpt_5_6_bedrock_spec.rb
+++ b/spec/ruby_llm/models_gpt_5_6_bedrock_spec.rb
@@ -5,6 +5,15 @@
 RSpec.describe RubyLLM::Models do
   include_context 'with configured RubyLLM'
 
+  # None of these three hand-added entries (see 7791056d) carry a
+  # cache_write_input_per_million rate, matching every other OpenAI-family
+  # model in models.json — no OpenAI model in this registry has that field
+  # modeled. This is consistent with, but NOT independently verified
+  # against, OpenAI/Bedrock pricing docs for GPT-5.6 specifically: whether
+  # Bedrock charges a distinct (non-zero) cache-write rate for these models,
+  # the way it does for Anthropic's cache_creation_input_per_million, is
+  # unknown. Revisit if models.dev adds real entries for these ids, or if
+  # OpenAI/AWS publish a documented cache-write rate for GPT-5.6.
   {
     'openai.gpt-5.6-sol' => { input: 5.0, output: 30.0, cache_read: 0.5 },
     'openai.gpt-5.6-terra' => { input: 2.5, output: 15.0, cache_read: 0.25 },