TexasCHLforum.com

Last I knew, in Texas any ordinary folding knife of less than 5 1/2 inch blade is not prohibited from carry.

An "Illegal Knife" is, however. Bigger that 5 1/2 inch blade, and it's an "Illegal Knife". I don't recall if a knife specifically designed to be a weapon is an illegal knife.

Be advised that San Antonio specifies it to be "unlawful" to carry any knife of blade less than 5 1/2 inches that "upon opening becomes a fixed blade knife". They don't define "fixed blade knife" anywhere, so I don't know if they mean the knife is no longer capable of being closed without the use of other tools, or if they mean to include knives where you have to operate a safety-catch release to close. They also do not specify any kind of punishment, or what degree of crime it is. (It may also be illegal to enforce, as the city ordinance also prohibits the carry of a 2-inch locking switchblade, which is already addressed in the State Law.)

Personally, I'm never without my Leatherman Wave, which has about 3.5 inch blade, or thereabouts.