I’m sure the man was ‘spying’. But given the time it took to get the information into the hands of anyone remotely close to Union high command, I have serious doubts as to the worth tactically or strategically.
Even in the 1860s, that information could be in Washington in a day. They had the telegraph, you know.
“But given the time it took to get the information into the hands of anyone remotely close to Union high command, I have serious doubts as to the worth tactically or strategically.”
I think you are right on the tactical point, but I think strategically it could have been of value. Since Union generals before Grant tended to vastly over estimate the strength and size of the Confederate armies one wonders how much information was really passed. This would, it seems to me, been one of the key bits of intelligence the slave/spy would have been privy to, and passed.