Agent-on-agent: when your bot becomes the payload
You ship an outer agent that plans. It spawns a "helpful" inner agent to dig, summarize, or call tools. Product demo looks clean. Trust model does not: classic confused deputy, just with LLMs.
The inner agent is often the one with broader tools, longer memory, or the system prompt that names secrets and schemas. Untrusted content does not need to jailbreak the outer model. It only needs to steer the inner one into echoing what it already knows, or calling a tool the outer agent would never have been allowed to call.
Your nested helper can become the payload. Prompt leak. Tool/schema leak. Same family of failure as approving an MCP server once and hoping every later tools/call is fine (MCP gateways).