The merge base read the variable by truthiness, so any non-empty value
turned the global flag on. Parsing it as a flag made a value such as
temperature or enabled silently turn it off, and the only docs for the
variable describe it as a list of parameter names, so keep those values
on and log a warning that asks for true or false. A blank value stays off
without a warning
A deployment drop_params string that is not a flag value (a typo like ture) stayed silently off. The router now logs one warning per deployment. LITELLM_DROP_PARAMS and litellm_settings.drop_params share the same helper, so a non-flag value there warns as well instead of flipping silently from on to off
get_litellm_params normalizes drop_params once, so a client-body string and
router_settings.default_litellm_params reach the anthropic, bedrock, and
azure_ai gates as a bool. LITELLM_DROP_PARAMS=false now means off. A value
that is neither a flag nor a string logs one warning and counts as unset,
both in the deployment validator and in litellm_settings.
