Whether a scribe must ask before writing a condition allowing collection of bound-properties & the value of improvements made to the property from the finest property automatically: Bava Metzia 14a, 15a
Other Issues
Including a condition which is against Torah law (Matneh Al Mah sheKatuv baTorah מתנה על מה שכתוב בתורה): Makkot 3b
The Legal Document may be written in any language: Gittin 19b
The Legal Document must be written with a writing which is in-alterable without being noticed: Gittin 11a, 19b, 20b, 21b
The Legal Document must repeat the essence of its point in the last line [preventing addition to it]: Gittin 11a, 19b
Writing a legal document on erased paper: Gittin 22b