IBM Bob

• Upgrading a large Java 8 or 11 application to Java 21 or 25 with a guided build, test, diagnose, and fix loop
• Explaining and documenting legacy RPG programs on IBM i, then refactoring them or extracting business rules
• Analyzing a COBOL or PL/I application on IBM Z and planning changes with a generated data dictionary
• Running Bob on an air-gapped OpenShift cluster with an open-weight model so source code never leaves the network
• Adding Bob Shell to a CI pipeline to generate documentation or analyze logs with JSON output and a cost cap
• Using Bob from IntelliJ IDEA, Neovim, or Zed through ACP instead of switching editors

Bob is worth a close look in two situations most coding agents do not cover well. One is modernization of IBM platforms: the IBM i and IBM Z packages work against real systems and mainframe languages, and the Java package wraps upgrades in repeatable, validated workflows. The other is deployment control: the self-hosted edition puts the whole backend on your own OpenShift cluster and can run fully air-gapped with an open-weight model. For everyday coding on a laptop, Bob is a capable agent with good governance, but its Bobcoin metering, the lack of an ongoing free tier, and IBM-controlled model routing on the SaaS service give individual developers fewer reasons to choose it over the tools they already use. Note that self-hosted Bob is a first release: one core model at a time, no Bobalytics, and no in-place upgrades.

About IBM Bob

Bob comes in two clients that share one agent harness. Bob IDE is a desktop editor for macOS, Windows, and Linux that installs VS Code extensions and can import your VS Code settings, and Bob Shell is a terminal agent that also runs non-interactively in scripts and CI/CD pipelines (`bob run` with JSON output and cost and turn caps) and as an Agent Client Protocol (ACP) server for IntelliJ IDEA, Neovim, Zed, and Xcode. Work happens in Agent, Plan, and Ask modes, Bob can spawn subagents with their own context windows and run several tool calls in parallel, and teams extend it with custom modes, rules, skills, lifecycle hooks, and MCP servers. Every state-changing action (file edits, commands, MCP calls) needs approval unless you auto-approve it. Three things set Bob apart from most coding agents. First, IBM-built premium packages add tested modernization workflows: Java upgrades from Java 8 or 11 to 17, 21, or 25 and WebSphere-to-Liberty migration, IBM i development against a live IBM i system (RPG, CL, SQL, DDS), and IBM Z analysis and refactoring for COBOL, PL/I, Assembler, and Java. Second, on the SaaS service IBM says Bob routes each task to a suitable model from a mix of Anthropic Claude, Mistral open models, IBM Granite, and its own fine-tuned models, and bills usage in Bobcoins (1 Bobcoin = $0.50) rather than per model. Third, since September 2026 a sales-led self-hosted edition runs the Bob backend on a customer-managed OpenShift cluster, connected either to a frontier model through the organization's own AWS Bedrock, Azure OpenAI, Google Vertex AI, or other OpenAI-compatible model service, or, on air-gapped networks, to an open-weight model such as NVIDIA Nemotron 3 or Poolside Laguna S2.1 on the organization's own GPUs. IBM describes Bob as the evolution of its earlier code assistants and gives existing watsonx Code Assistant customers an adoption path to it. The tradeoffs: plans are metered in Bobcoins, so heavy agent use can mean overage charges, the self-hosted edition runs one core model at a time and lacks some SaaS features, and the strongest reasons to choose Bob (mainframe and IBM i modernization, on-premises deployment) matter most to large IBM customers.