OpenAI subagents provide parallel work with separate contexts, but share the session's filesystem and inherit MCP tools and credentials. This is useful inside one agent workload. Independent fleet members with different trust boundaries still need separate environments and policy.
Internal delegation and fleet isolation
Agents API supplies subagent creation, messaging, waiting, and interruption. Subagents have their own contexts and can work in parallel.
When a session has an environment, coordinator and subagents share its filesystem; spawning does not create another environment. Subagents inherit MCP tools, credentials, and allowed tools. Function tools are currently unsupported for subagents.
Architectural implication: use this for bounded specialists within one workload. A researcher and publisher with different permissions still require isolation and policy outside this delegation mechanism. Preserve the fleet's permission boundary.