diff --git a/.env.example b/.env.example
index 17ad95d27..02b1147b8 100644
--- a/.env.example
+++ b/.env.example
@@ -61,7 +61,7 @@ VERTEX_EMBED_CONTENT_MODEL=gemini-embedding-001
 
 # Noise / Relevance Filter (Module B)
 
-CRE_NOISE_FILTER_LLM_MODEL=gemini/gemini-2.5-flash-lite
+CRE_NOISE_FILTER_LLM_MODEL=gemini/gemini-3.5-flash-lite
 CRE_NOISE_FILTER_BATCH_SIZE=10
 CRE_NOISE_FILTER_MAX_CHARS=1500
 CRE_NOISE_FILTER_CONFIDENCE_THRESHOLD=0.8
diff --git a/application/utils/noise_filter/config_loader.py b/application/utils/noise_filter/config_loader.py
index 7462b3bc8..d4a47037b 100644
--- a/application/utils/noise_filter/config_loader.py
+++ b/application/utils/noise_filter/config_loader.py
@@ -24,7 +24,7 @@
 # Cheap, dedicated classification model. Decoupled from CRE_LLM_CHAT_MODEL by
 # design: Module B is the cheap gate and must not pull in the chatbot's
 # heavier model.
-DEFAULT_LLM_MODEL = "gemini/gemini-2.5-flash-lite"
+DEFAULT_LLM_MODEL = "gemini/gemini-3.5-flash-lite"
 DEFAULT_BATCH_SIZE = 10
 DEFAULT_MAX_CHARS = 1500
 DEFAULT_CONFIDENCE_THRESHOLD = 0.8
diff --git a/application/utils/noise_filter/llm_classifier.py b/application/utils/noise_filter/llm_classifier.py
index 21796b19e..61464fb6e 100644
--- a/application/utils/noise_filter/llm_classifier.py
+++ b/application/utils/noise_filter/llm_classifier.py
@@ -4,7 +4,7 @@
 construct PromptHandler (DB-coupled). Completions go through
 ``application.prompt_client.litellm_router`` so retry policy and parsing match
 chat/embeddings. The classifier uses a dedicated cheap model
-(config.llm_model, default gemini/gemini-2.5-flash-lite) and never falls back
+(config.llm_model, default gemini/gemini-3.5-flash-lite) and never falls back
 to CRE_LLM_CHAT_MODEL: Module B is the cheap gate and must stay decoupled
 from the chatbot's model.
 """
diff --git a/docs/gsoc_2026_module_b/module_b_runbook.md b/docs/gsoc_2026_module_b/module_b_runbook.md
index 43c2a9e94..f1d71a44d 100644
--- a/docs/gsoc_2026_module_b/module_b_runbook.md
+++ b/docs/gsoc_2026_module_b/module_b_runbook.md
@@ -36,7 +36,7 @@ vector;`).
 | Var | Purpose | Default |
 |---|---|---|
 | `GEMINI_API_KEY` | LLM credential (Gemini) | — (required) |
-| `CRE_NOISE_FILTER_LLM_MODEL` | classification model | `gemini/gemini-2.5-flash-lite` |
+| `CRE_NOISE_FILTER_LLM_MODEL` | classification model | `gemini/gemini-3.5-flash-lite` |
 | `CRE_NOISE_FILTER_BATCH_SIZE` | chunks per LLM request | `10` |
 | `CRE_NOISE_FILTER_MAX_CHARS` | per-chunk truncation | `1500` |
 | `CRE_NOISE_FILTER_CONFIDENCE_THRESHOLD` | KNOWLEDGE-below → UNCERTAIN | `0.8` |