Freeze agent role configuration at spawn

Status: accepted

Spawning resolves and snapshots the agent's role, instructions, tools, base model, reasoning effort, and inherited configuration. That snapshot remains stable across follow-up turns and session resume; later role-definition or default changes affect only newly spawned agents. Session-wide permissions, explicit denies, protected resources, and confinement remain dynamic outer controls and may tighten without changing the retained conversation identity.

For inherited default roles, tools include both native request tools and the effective specialist catalog. Specialist membership is recorded as explicit category/name tool specs in the frozen role, using the existing configuration codec. Recursive children inherit their immediate caller's effective catalog; named roles retain their own specs. Frozen identities do not freeze tool handlers or bypass current availability and permission checks.

Decision history

• Complete tool inheritance, 2026-10-14: a default Claude Code child inherited seven native tools but none of its parent's 46 specialists, so it could not discover SendMessage or any other specialist. Only native request locals had been inherited; the default role's empty tool specs seeded an empty catalog. Default effective specs now include the caller's specialist identities, filtered by its request's callable roster. The existing freeze and restore path retains them without a separate catalog format or a communication-tool exception.