What reaches a sub-agent: the agent body and project rules you wrote, plus a task prompt generated on your behalf

My Sub-Agent Followed an Instruction I Never Wrote

Three inputs cross into a sub-agent’s context window. You write two of them. The third is generated on your behalf, never shown to you, and it is the one that overrode a strict output format. Includes the token cost of delegating, measured.

August 15, 2026 · 5 min · Jack Monte