Pattern 1: Orchestrator-worker
One orchestrator agent decomposes the task and dispatches subtasks to worker agents. Each worker has a narrow tool set and a narrow context window. Results stream back to the orchestrator for synthesis.
Ships well for: document processing, multi-source research, code refactors across many files.
Fails when: subtasks depend on each other in non-obvious ways. The orchestrator can't see the cross-cut.