The economics of IBM Power modernisation have always been challenging. The specialist skills required are expensive and increasingly scarce. The risk of getting something wrong in a thirty-year-old codebase is significant. And the pace at which traditional approaches can move is rarely fast enough to satisfy the commercial pressure to modernise.
IBM Bob changes that calculation. Not incrementally, materially. Bob is IBM’s AI-powered Software Development Lifecycle partner, built specifically for the complexity of enterprise development environments. It brings capabilities to modernisation programmes that simply were not available before.
At Northdoor, as an IBM Gold Business Partner with deep IBM Power expertise, we have been closely watching how Bob operates in practice. What Bob represents is not another coding assistant. It is a fundamentally different approach to how AI can support large-scale application transformation and for organisations running IBM i, AIX, and legacy enterprise applications, it arrives at exactly the right moment.
IBM Bob is not another coding assistant. It is a fundamentally different approach to how AI can support large-scale application transformation. Share on XThe problem IBM Bob was built to solve
Most AI coding tools are designed for greenfield development. They help developers write new code faster. That is genuinely useful. However, it does not address the hardest part of modernisation: understanding and safely transforming existing code.
Legacy IBM Power applications present challenges that generic AI tools cannot handle. The codebases are complex, deeply interdependent, and typically underdocumented. Business logic is embedded across thousands of RPG and COBOL programmes. Making a change in one module can have consequences three or four dependencies away that neither the developer nor the AI tool anticipated.
Traditional AI coding assistants help in isolation but break down across systems. They can suggest how to rewrite a function. However, they cannot tell you what that function does in the wider application, which programmes depend on it, or what will break if the underlying data structure changes.
Bob was built to operate at the system level, not the function level. That distinction matters enormously in IBM Power modernisation programmes.
What IBM Bob does differently for legacy modernisation
Bob describes itself as an AI SDLC partner, and that framing is deliberately more ambitious than a coding assistant. The difference lies in four capabilities that are directly relevant to IBM Power modernisation.
Deep context awareness
Bob maintains a shared, system-level understanding of the codebase, spanning code, configurations, and dependencies, and uses that context when reasoning about any proposed change. In a legacy IBM i environment, where RPG programmes reference data structures, call programmes, and interact with database files in ways that are rarely obvious from the code alone, this is transformative.
End-to-end task orchestration
Rather than suggesting a code change and leaving the developer to implement it manually across multiple files, Bob can coordinate changes across the codebase, handling the complex chain of modifications that a single modernisation decision often requires. This directly addresses one of the most expensive aspects of legacy transformation — the manual effort of propagating changes safely and consistently at scale.
Built-in governance and auditability
Bob gates changes through approval workflows, explains the reasoning behind its recommendations, and maintains an auditable trail of every modification. For regulated industries, and many IBM i customers operate in financial services, healthcare, or the public sector, this is a prerequisite for confident modernisation.
AI-generated documentation
Bob can analyse undocumented legacy code and produce structured, plain-language documentation of what programmes do, how they interact, and where business logic resides. Many organisations are operating in a state of knowledge fragility. Critical application knowledge lives in the heads of two or three people approaching retirement. This capability alone represents significant risk reduction.
Bob maintains a live, system-level picture of the application landscape, spanning code, configurations, and dependencies. In a legacy IBM i environment, that is transformative. Share on XIBM Power modernisation results: What the numbers show
IBM has deployed Bob internally across its own development teams, and the results provide a credible reference point for what modernisation programmes can realistically expect.
These are not pilot statistics from a controlled experiment. They reflect enterprise-wide adoption across one of the world’s largest technology organisations. The near-universal activation rate after onboarding, and the sustained 65% daily active usage, suggest that Bob fits naturally into how developers actually work — the most reliable predictor of whether AI tooling delivers durable value.
The most commercially important metric for IBM Power modernisation programmes is the 90% reduction in effort for repetitive tasks. Legacy transformation is disproportionately burdened by exactly this kind of work: repetitive pattern analysis, documentation of known structures, consistent application of refactoring rules across large codebases. Automating that work changes what is economically viable.
The 90%+ reduction in effort for repetitive tasks directly reduces dependency on scarce specialist capacity and changes what is economically viable in a modernisation programme. Share on XIBM Bob’s modernisation capabilities in practice
IBM identifies legacy modernisation and code migration as one of the five areas where Bob delivers fastest time-to-value. The specific capabilities relevant to IBM Power environments include:
- Understanding the full system before change. Bob aligns modernisation work with existing branching and team workflows before any changes begin. This is a critical step that traditional approaches often shortcut, with costly consequences.
- Accelerating modernisation without manual rework. Bob handles the repetitive, pattern-based work of refactoring at scale. That frees specialist developers to focus on the complex judgement calls that genuinely require human expertise.
- Making large-scale change safe and repeatable. By coordinating changes across the codebase rather than making isolated modifications, Bob reduces the risk of unintended consequences in interdependent legacy systems.
- Turning undocumented code into shared knowledge. AI-generated documentation transforms tacit knowledge into structured, accessible organisational assets.
- Validating changes before they matter. Shift-left security and integrated testing within Bob’s workflows means issues surface during development, not in production.
For IBM i organisations specifically, Bob’s support for RPG, COBOL, and enterprise systems modernisation is a named capability. This reflects IBM’s recognition that the IBM Power installed base represents one of the most significant modernisation opportunities in enterprise technology.
How IBM Bob fits a phased modernisation approach
At Northdoor, our approach to IBM Power modernisation has always been phased and risk-managed. We do not advocate for big-bang transformation programmes. The risk profile is unacceptable for systems that underpin live business operations. Bob fits naturally into a phased approach and, in some respects, makes it more effective than it has previously been.
Discovery and assessment
Bob’s deep codebase analysis accelerates the work of understanding what exists. It maps dependencies, identifies business logic, and surfaces the complexity that needs to be accounted for in the modernisation roadmap.
Refactoring and migration
Bob’s orchestration capabilities and shift-left governance mean that changes can be made at scale with confidence — with every modification explained, audited, and validated before it progresses.
Knowledge transfer
Often treated as an afterthought, knowledge transfer is critical to long-term success. Bob’s documentation generation creates the institutional knowledge base that organisations need to own and operate their modernised applications independently.
Across all phases, Bob reduces the dependency on the small number of individuals with deep legacy expertise. It does not eliminate the need for those people. Their judgement remains essential. However, it makes them significantly more productive and means that programmes are less vulnerable when key individuals leave.
A Northdoor perspective on IBM Power modernisation
We have been helping organisations get more from IBM Power platforms for years. The modernisation challenge is one we know well: the technical complexity, the organisational sensitivity, the commercial pressure, and the skills constraints that make it difficult to move at the pace the business requires.
Bob represents the most significant practical advance in AI-assisted modernisation tooling we have seen. It addresses the right problems: system-level understanding, safe large-scale change, documentation generation, governance. The evidence from IBM’s own internal deployment suggests it delivers at enterprise scale, not just in controlled pilots.
For Northdoor clients considering IBM Power modernisation, the question we are now encouraging them to ask is not just ‘what is our modernisation roadmap?’ It is ‘how does Bob change what that roadmap can achieve, at what speed, and at what cost?’ In many cases, programmes that previously looked too complex or too expensive become significantly more tractable.
That is not a trivial change. For organisations that have been deferring modernisation decisions, and the window for managed, planned transformation does not stay open indefinitely, it may be the change that makes the difference between acting confidently and reacting in crisis.