AI Tools for IBM i Developers in 2026: What Actually Works

IBM i developers occupy a specific corner of the software world that most AI tooling completely ignores. The training data for general-purpose models skews hard toward JavaScript, Python, and Java. RPG IV, CL, DDS, and the IBM i ecosystem have thin coverage, which means the usual AI coding assistant recommendations don’t translate cleanly.

This article covers what actually works for IBM i developers in 2026, from purpose-built tools to workarounds that get useful results from general-purpose models.

The State of AI for IBM i in 2026

The situation has improved significantly in the past 18 months. In 2024, asking Claude or GPT-4 to write RPG IV got you plausible-looking code that didn’t compile and made structural assumptions from the AS/400 era that don’t hold in modern free-format RPG. In 2026, the picture is more nuanced.

IBM shipped two purpose-built tools. General-purpose models have gotten better on IBM i as more developers contribute prompts, examples, and corrections to the training corpus. And a small ecosystem of third-party modernization vendors has added AI capabilities to their platforms.

The result: IBM i developers now have real options, with clear trade-offs between each.

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IBM Project Bob

IBM Project Bob is a VS Code-based AI coding assistant built specifically for IBM i, announced in early 2026. It supports RPG, CL, DDS, and SQL for IBM i, with a fine-tuned model that understands the IBM i execution environment, program call interfaces, and data structure conventions that general models don’t.

What Project Bob does:

• Explains legacy RPG code in plain English, particularly useful for the fixed-format RPG/400 and OPM code that still runs at many shops
• Generates documentation for programs and procedures
• Answers questions about IBM i-specific behavior: job logs, spooled files, data queues, activation groups
• Provides code completion that understands free-format RPG IV syntax correctly

What it can’t do yet:

• Full program generation from scratch at production quality
• Full modernization from fixed-format to free-format without manual review
• CL program analysis at the depth of a dedicated tool

Project Bob is IBM’s entry into the AI coding assistant space for IBM i, and it’s a meaningful starting point. The June 2026 Premium Package for i is the release that made it usable directly on the box instead of on a copy of your source. The VS Code integration is cleaner than most IBM i developer tooling has historically been.

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IBM watsonx Code Assistant for i

watsonx Code Assistant for i is IBM’s more comprehensive offering, positioned at organizations doing systematic IBM i modernization. It uses a Granite code model fine-tuned specifically for RPG and IBM i, with deeper integration into the modernization workflow.

Capabilities in 2026:

• Explain, document, and annotate RPG programs
• Identify modernization candidates, procedures that are candidates for conversion to service programs, or programs with complex control flow that would benefit from refactoring
• Generate free-format RPG from fixed-format (with review, not production-ready without validation)
• SQL assistance for DB2 for i

The honest assessment: watsonx Code Assistant for i is most useful as a documentation and explanation tool, and as an accelerator for modernization projects under professional services. The code generation is better than general models on RPG, but the output requires experienced IBM i developer review before it goes anywhere near production.

Pricing is enterprise, not self-serve. If you’re evaluating it for a modernization project, get a demo through IBM or a partner.

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General-Purpose AI on IBM i Code

This is where things get practical for IBM i developers who aren’t running a formal modernization project and just want help with day-to-day code.

Claude and GPT-4o both handle IBM i better in 2026 than they did in 2024. With the right prompting, you can get genuinely useful output. The key is giving the model explicit context it doesn’t have by default.

Prompts that work

For code explanation:

I'm working with IBM i (AS/400). This is free-format RPG IV code. 
Explain what this program does, what external programs it calls, 
and what the key data structures represent.

[paste code]

For documentation generation:

Generate internal comments for this RPG IV procedure. 
Assume the reader is an experienced programmer but unfamiliar with 
this specific business function. Use // comments in free-format style.
Explain the purpose of each major block, not every line.

[paste procedure]

For SQL help on DB2 for i:

This SQL runs on DB2 for i (IBM i database). Help me optimize this query.
Note that the system uses logical files and physical files, 
and this runs in a batch job context with an active job description.

[paste SQL]

For debugging:

This RPG IV program is producing unexpected output. 
The IBM i job log shows [paste relevant job log entries].
The issue appears in the [describe section] of the program.
Walk me through what the code is doing and what might cause this output.

[paste code section]

What works well

General models are good at:

• Explaining code they haven’t seen before, when given enough context
• Translating RPG IV logic to equivalent pseudocode or Python for a team member to understand
• Writing DB2 for i SQL queries when you specify the environment
• Generating documentation and comments
• Explaining IBM i concepts (activation groups, binding directories, service programs) when asked

What doesn’t work well

General models still struggle with:

• Fixed-format RPG, they tend to generate incorrect column positions and mix free-format syntax into fixed-format programs
• CL programs with complex job management logic
• Physical file/logical file relationships, they default to relational table assumptions
• IBM i-specific APIs (QCMDEXC, message queue programs, data area reads)

The workaround for these gaps: describe the construct in plain English rather than asking the model to generate it. “I need to call QCMDEXC to run a command from within an RPG program, what are the parameter requirements?” gets a useful answer. “Write a CL program that monitors a message queue” does not.

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Third-Party Modernization Tools with AI

Several IBM i modernization vendors have added AI capabilities to their platforms:

Fresche X-Modernize AI: Focused on RPG-to-Java conversion. AI assists in extracting business rules from RPG code and generating the target code. Most useful for shops with a formal migration project and a target platform already chosen. We reviewed it in depth, including why there’s no public price and how to read the vendor’s speed claim.

Andorsoft: Handles RPG and COBOL modernization with AI-assisted code documentation as the entry point. The documentation pass is valuable independently of whether you’re doing a full migration.

Kodesage: AI-assisted RPG modernization with a focus on free-format conversion and code quality improvement within IBM i, rather than platform migration.

These tools are best evaluated in the context of a specific project, a trial against your actual codebase is more informative than any benchmark.

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Practical Recommendations

For day-to-day IBM i development: Use Claude or GPT-4o with context-rich prompts. Copy the prompt patterns above and customize them for your shop’s conventions. General models are useful for documentation, explanation, and SQL at this point.

For a formal modernization project: Evaluate IBM watsonx Code Assistant for i and at least one third-party tool (Fresche, Andorsoft) side by side against a sample of your actual codebase. The right tool depends on your target platform and your team’s capacity to review and validate AI output.

For a VS Code-curious IBM i shop: IBM Project Bob is worth a pilot. The VS Code integration is the cleanest IBM i developer experience available right now outside of traditional tools like RDi. If you’re still deciding which to use, the VS Code vs RDi comparison for IBM i in 2026 has a clear answer now that the survey data has shifted.

For code documentation as a standalone project: This is the highest-confidence AI use case on IBM i. For prompt templates and a full repeatable workflow, see Documenting RPG IV code with AI. Claude with the right prompts produces useful, accurate documentation for free-format RPG IV. Fixed-format programs need more human review but the model still gets you 70-80% of the way there.

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Frequently Asked Questions

Can ChatGPT write RPG IV code?

For simple, isolated procedures, yes, with review. For anything that touches IBM i-specific APIs, job management, or complex file processing, the output needs significant correction. Provide explicit context (“this is free-format RPG IV for IBM i, not RPG III or any other language”) in every prompt.

What is IBM Project Bob?

IBM Project Bob is IBM’s VS Code-based AI coding assistant for IBM i developers, launched in 2026. It supports RPG, CL, DDS, and SQL for IBM i with a model tuned specifically for IBM i code.

Is there an AI tool that can convert RPG IV to Java?

Yes. Fresche’s X-Modernize AI and IBM watsonx Code Assistant for i both target this use case. Neither produces production-ready Java without human review, they accelerate the conversion workflow, not replace it.

How do I get better AI results for IBM i code?

The biggest improvement comes from explicit context in every prompt: specify the language version (free-format RPG IV, fixed-format RPG/400), the platform (IBM i, not AS/400, use the current terminology), and any IBM i-specific context relevant to the problem. Don’t assume the model knows your environment.

Will AI replace IBM i developers?

No. IBM i shops have complex business logic built up over decades, running on a platform that requires specific operational knowledge. AI tools accelerate documentation, modernization, and routine development tasks. The business knowledge, the system knowledge, and the judgment to validate AI output all stay with the developer. When that developer leaves, the programs keep running but the knowledge does not.

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Related reading

For the hands-on workflow with specific prompt templates: Documenting RPG IV Code with AI.

Going Deeper

If you’re running a documentation project or preparing for retirements on your IBM i team, the IBM i AI Field Guide covers the full workflow: a complete documentation process, 35 IBM i-specific prompt templates, knowledge transfer playbook, and modernization planning. It’s built specifically for IBM i shops and goes significantly further than what fits in an article.