The biggest risk is probably a drifting focus towards improving that tool. Unless there is some overall strategy towards segmenting out pieces and moving those

The biggest risk is probably a drifting focus towards improving that tool. Unless there is some overall strategy towards segmenting out pieces and moving those into OSS, finding maintainers/audience, having an actual plan around those repos... I think your intuition of avoiding it is correct. If it's already releasable (carved out into it's own repo, parsed for any possible security breaches, independently runnable, etc.) You can just make that public with no fan fare and agree not to do anything with it for a month or two. Let your excitement die down, see if anyone notices it or cares, then evaluate at some future date what could happen with it. If you decide no, just make it private again