  We present Safe Surgery by Identifying Pushouts (SSIP), an open-source
lightweight Python package for automating surgery between qubit CSS codes. SSIP
is flexible: it is capable of performing both external surgery, that is surgery
between two codeblocks, and internal surgery, that is surgery within the same
codeblock. Under the hood, it performs linear algebra over $\mathbb{F}_2$
governed by universal constructions in the category of chain complexes. We
demonstrate on quantum Low-Density Parity Check (qLDPC) codes, which are not
topological codes in general, and are of interest for near-term fault-tolerant
quantum computing. Such qLDPC codes include lift-connected surface codes,
generalised bicycle codes and bivariate bicycle codes. We show that various
logical measurements can be performed cheaply by surgery without sacrificing
the high code distance. For example, half of the single-qubit logical
measurements in the $Z$ or $X$ basis on the $[[ 144 ,12, 12 ]]$ gross code
require only 30 total additional qubits each, assuming the upper bound on
distance given by QDistRnd is tight. This is two orders of magnitude lower than
the additional qubit count of 1380 initially predicted by Bravyi et al.
