Most agent failures are not prompt failures. They are routing failures.
You ask one model to do everything, then blame the prompt when the job needed different kinds of intelligence at different moments.
The pattern
Use the model that fits the step:
- Claude for long-context synthesis and careful writing.
- GPT for tool-heavy workflows and structured execution.
- Gemini when the job needs speed, breadth, or large context at low cost.
The rule
Do not route by brand preference. Route by job shape.