Module resolver 

Routing resolver — dynamic agent resolution at spawn time. Slotted into the SpawnerStack as a SpawnerLayer. Treats Ctx.agent as a hint, rewrites it to the actual dispatch target, and hands the updated Ctx down to the inner spawner.

Examples:

• Ctx.agent = "best-coder" — the resolver picks claude or gpt-4 or llama.
• Ctx.agent = "router:by-prompt" — branch on prompt contents.
• Ctx.agent = "ensemble" — fan out to multiple agents (delegated to a different layer or a fanout stage).

One of the axes that a plugin can drive (see handoff §Plugin).

Structs

FnResolver

Wrapper that lets a closure act as an AgentResolver via a blanket impl.

ResolverMiddleware

SpawnerLayer implementation — inject into a SpawnerStack and use.

Traits

AgentResolver

Routing resolver trait. Takes the Ctx.agent hint and returns a real agent name the inner spawner can resolve. Sync is enough — this is meant for light lookups. Push heavy resolvers into a separate spawner layer or a Lua plugin.