Before adding another subagent ask what problem it's solving. A bloated system prompt is often the issue.

Skills and tool search can fix that without splitting context across agents. My rule of thumb is to keep a subagent when the work is parallel, needs fresh context or one agent really can't pick the right tools.

Otherwise, fold it into the main loop, turn its prompt into a skill, run your evals and keep whatever wins.

Good write-up:
https://claude.com/resources/articles/building-agents-when-to-fold-subagents-into-your-main-agent-loop