Very interesting concept, thanks for sharing! Context and intent are critical when trying to understand code - this looks like a useful way to capture that. Merging the call stack display with the "debugger" is IMHO a particularly good idea.

Out of curiosity: have you explored stories for code _over time_ at all? It might be useful to be able to build stories for a block of code that change from commit to commit as the code itself is mutated.