diff --git a/docs/v3/contributing/configuration.mdx b/docs/v3/contributing/configuration.mdx
index 7d4fe2b2..076ec465 100644
--- a/docs/v3/contributing/configuration.mdx
+++ b/docs/v3/contributing/configuration.mdx
@@ -302,6 +302,7 @@ DERIVER_ENABLED=true
 DERIVER_MODEL_CONFIG__TRANSPORT=openai
 DERIVER_MODEL_CONFIG__MODEL=gpt-5.4-mini
 DERIVER_MAX_INPUT_TOKENS=25000
+DERIVER_MAX_CUSTOM_INSTRUCTIONS_TOKENS=2000
 # DERIVER_MODEL_CONFIG__THINKING_EFFORT=minimal
 # DERIVER_MODEL_CONFIG__THINKING_BUDGET_TOKENS=1024
 # DERIVER_MODEL_CONFIG__TEMPERATURE=0.7  # Optional temperature override