Agents & MCP
Subagent
A smaller agent spawned by a parent agent to handle a piece of the work. Subagents let one task fan out into many, which is powerful — and a spend-attribution challenge, because their cost needs to roll back up to the agent that launched them.
Example
A research agent spawns five subagents, one per competitor, each running its own calls in parallel. To see the true cost, each subagent's spend has to roll up to the parent agent, which rolls up to the project — otherwise "the agent" is a mystery cost buried in someone's key.
Related terms
AI agent
An AI system that doesn't just answer once but works toward a goal over multiple steps — planning, calling tools, reacting to results, and looping until done. Because an agent can make many calls per task, it can spend far more than a single prompt, and it spends without a human watching each step.
Agent identity
Giving an autonomous agent its own distinct identity — its own key, budget, and record — rather than having it act under a human's credentials. Without it, an agent's spend and actions are indistinguishable from the person who launched it.
Cost attribution
Tying each dollar of AI spend to who spent it and why — the person, team, project, or agent responsible — rather than seeing one lump sum on a provider invoice. Attribution is the difference between "we spent $40,000 on AI" and "the research team's document pipeline spent $40,000."