LangEx.Prebuilt.Member (LangEx v0.11.3)

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Builds a routable team-member agent for LangEx.Prebuilt.Swarm and LangEx.Prebuilt.Supervisor.

A member is an ordinary tool-calling agent (LLM node plus tool node) compiled as its own graph, with one extra behaviour: it tracks an :active_agent state key. While :active_agent names the member itself the tool loop continues; once a handoff tool points it at a different agent the member ends its turn so the enclosing team can route control onward.

build/1 returns the compiled member graph; node/3 wraps it as a parent-graph node that runs one turn and contributes only the messages it produced (so a shared conversation is not duplicated on every hop). The team's runtime context is forwarded into each member turn, and each turn's token usage is contributed back under :llm_usage.

A member runs its turn as a nested execution, so a LangEx.Interrupt raised inside a member is not resumable across the team boundary — node/3 surfaces it as an error instead. Keep human-in-the-loop pauses at the team level.

Summary

Types

output_mode()

How much of a member's turn is contributed back to the team.

Functions

active_agent_key()

The state key a team uses to track which agent holds the conversation.

build(opts)

Builds and compiles a member agent.

node(member, name, output_mode)

Wraps a compiled member as a parent-graph node.

tool_router(name)

Routing function for a member's tool node: keep looping while this member is active, otherwise end the turn so the team can re-route.

Types

output_mode()

@type output_mode() :: :full_history | :last_message

How much of a member's turn is contributed back to the team.

Functions

active_agent_key()

@spec active_agent_key() :: atom()

The state key a team uses to track which agent holds the conversation.

build(opts)

@spec build(keyword()) :: LangEx.Graph.Compiled.t()

Builds and compiles a member agent.

Options

  • :name (required) - the member's own name; also its :active_agent identity
  • :tools - the member's own %LangEx.Tool{} list (default [])
  • :handoff_tools - handoff %LangEx.Tool{} list appended to :tools
  • :system_prompt - a string, or a 1-arity function (state -> string) for a dynamic prompt; prepended when the conversation has no system message
  • :compaction - forwarded to LangEx.ContextCompaction.compact_if_needed/2; false disables
  • :tool_opts - forwarded to LangEx.Tool.Node.node/2
  • :store - long-term memory backend
  • :pre_model_hook - (messages -> messages) applied to the message list just before the LLM call (e.g. trimming or extra instructions)
  • :post_model_hook - (update -> update) applied to the node result map after the LLM call (e.g. guardrails)
  • all other options (:model/:provider, :temperature, ...) are forwarded to LangEx.LLM.ChatModel.node/1

node(member, name, output_mode)

@spec node(LangEx.Graph.Compiled.t(), atom(), output_mode()) ::
  (map(), term() -> map())

Wraps a compiled member as a parent-graph node.

The node runs one member turn seeded with the shared conversation and the member's own name as the active agent, then returns just the messages produced this turn (per output_mode), the resulting :active_agent, and the turn's :llm_usage. The enclosing team's runtime context is forwarded into the member turn.

tool_router(name)

@spec tool_router(atom()) :: (map() -> :agent | :__end__)

Routing function for a member's tool node: keep looping while this member is active, otherwise end the turn so the team can re-route.