How Harvey Scaled Agent Development with Tool Bundles, No Custom Orchestration, and Eval Gates
Harvey's Assistant product hit a UX, engineering, and collaboration wall as new features accumulated: users weren't discovering Draft mode, multiple retrieval calls were complex to maintain behind a single interface, and new integrations had no clear path to launch. As more engineers touched the monolithic system prompt, their goals conflicted with no safe contribution model.
How it works
Common implementation structure
How this type of workflow is generally built, generalized across documented cases — not tied to any one vendor's stack. Click any stage to read what happens there. Specific products that implement these stages appear in “Tools commonly seen” below.
Stage 1 · Developer creates Tool Bundle
Feature and integration developers package new capabilities—composed of multiple tools or sub-agents—into a Tool Bundle.
Tools used
OpenAI Agent SDK
Outcome
Adopting a single agent framework with Tool Bundles and eval gates scaled Harvey's in-thread feature development from one team to four, led to emergent feature combinations, and enabled centralized eval.
What failed first
Pre-agent bespoke orchestration meant engineers' goals could directly collide in the shared system prompt—one developer pushing for more tool recall and another for lower latency would overwrite each other's instructions, with no unit-testable boundary between them.