Integrating agentic AI with legacy enterprise systems requires a disciplined engineering approach rather than direct access. The core pattern is wrapping legacy APIs, screens, and workflows behind narrow, auditable, agent-safe tools that represent business capabilities rather than low-level operations. Key practices include normalizing legacy responses, validating inputs server-side, separating read-only from state-changing tools, requiring human approval for high-risk actions, and logging everything. Agents are also valuable for system discovery and documentation generation, but findings must be validated by engineers and subject matter experts. Screen-based automation (RPA) is a last resort and should be hidden behind controlled tool abstractions. The recommended modernization path is incremental: wrap existing capabilities, observe agent usage patterns, then prioritize what to replace or refactor.

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Table of contents
Legacy Systems Are Not the EnemyThe Common Mistake: Letting Agents Touch Everything DirectlyWorking with Outdated APIs and Brittle InterfacesWrapping Legacy Systems with Agent-Safe ToolsHandling Missing Documentation Without Guessing Your Way into ProductionUsing Agents for System Discovery and Process MappingScreen-Based Automation: Useful, Fragile, and Usually a Last ResortReliability Starts with Tool Contracts, Not Model PromptsModernization Strategies Enabled by AgentsThe Common Way vs. the Better WayPractical Checklist for Integrating Agents with Legacy SystemsDevelopers Still Own the BoundariesFinal ThoughtsKey Takeaways
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