RuleScope: Know Before You Code

No developer can remember every line of a codebase, but every line still runs. Developers spend about 58% of their time just understanding existing code (Xia et al., IEEE TSE 2018), and a change that wakes up forgotten code can be very expensive: Knight Capital lost $440M in 45 minutes in 2012. THE PROBLEM A ticket says "raise the Premium transfer limit to €5,000". It looks like a one-line change. It isn't: the same limit is copied in the mobile app, a fraud rule silently blocks anything above €2,000, a compliance report depends on the same amounts, and tests assume the old value. Teams usually discover this in code review, QA or production. THE SOLUTION RuleScope makes IBM Bob investigate first. In our custom RuleScope mode, Bob follows the impact-brief skill, runs one subagent per repository in parallel, and calls our rulescope-mcp server to search the code, read git history, measure test coverage and simulate the naive change in a temporary copy. The real code is never touched. THE RESULT: AN IMPACT BRIEF Shown in Bob's chat and as a web report: the questions to settle before coding and who must sign off; every file to change, to check or not affected, with the exact lines; hidden duplicates and cross-repository links; a before/after table proving what the naive fix breaks; git history, coverage gaps, risk, effort and a safe step-by-step plan. A finding without evidence is refused before saving. WHO IT IS FOR Engineering teams on complex, regulated, multi-repository systems: banks, insurers, fintech. They never paste private code into a website: RuleScope runs inside IBM Bob, on the developer's machine and private repositories. When the developer asks, the same Bob session applies the plan in Agent mode. THE DEMO NovaBank: two linked repositories (API and mobile app) with synthetic data. Premium limit: finds the mobile duplicate and the fraud