Solo workflow

Topology

One ensemble process owning one sub-agent owning one backend session. The simplest useful ensemble.

+-------+    +---------+    +----------+
|  E.*  | -> |  Solo   | -> |  agent   | -> backend
+-------+    +---------+    +----------+

When to reach for it

• You want a single LLM session you can talk to by name.
• You want the conversation history to persist across turns.
• You're prototyping before adding coordination.
• You have a "REPL-for-task-X" shape: "ask the Elixir reviewer", "ask the docs writer", "ask the SQL coach".

For anything with concurrency or multi-stage logic, reach for Pool, Pipeline, or Supervisor instead.

Config

config :gen_agent_ensemble,
  ensembles: [
    [
      name: "solo",
      strategy: GenAgentEnsemble.Strategies.Solo,
      opts: [
        agent:
          {"w", GenAgentEnsemble.Agents.Simple,
           backend: GenAgent.Backends.Anthropic,
           system: "You are a pragmatic Elixir reviewer.",
           model: "claude-sonnet-4-6"}
      ]
    ]
  ]

Canonical workflow

One-shot synchronous turn

iex> E.ask!("solo", "what's wrong with Enum.map(list, &(&1 + 1))?")
"Nothing -- that's idiomatic Elixir..."

iex> E.ask!("solo", "now rewrite that as a Stream pipeline")
"Stream.map(list, &(&1 + 1)) |> Enum.to_list()"

The second call sees the first as conversation history. Token usage grows each turn because the backend resends the full message array.

Async (fire-and-check-later)

iex> {:ok, token} = E.tell("solo", "explain ETS in one paragraph")
{:ok, "tok-5"}
iex> # ...do other work...
iex> E.await("solo", token) |> E.puts()
ETS (Erlang Term Storage) is an in-memory key-value store...
:ok

Inspect

iex> E.status("solo")
{:ok, %{
  session: "solo",
  strategy: GenAgentEnsemble.Strategies.Solo,
  agent: "w",
  queued_tokens: 0,
  agents: ["w"],
  in_flight: 0,
  pending_tokens: []
}}

Variations

• Swap backends. Change backend: to any GenAgent.Backend implementation (Anthropic, Claude, OpenAI, Codex, GenAgentEnsemble.Backends.Echo, your own).

• Pass cwd for file-aware backends. Claude CLI honours :cwd:

  agent:
    {"w", GenAgentEnsemble.Agents.Simple,
     backend: GenAgent.Backends.Claude,
     cwd: "/path/to/project",
     permission_mode: :plan,
     system_prompt: "You are a code reviewer."}

• Custom callback module. Replace GenAgentEnsemble.Agents.Simple with your own use GenAgent module when you want richer state or prompt-engineered behaviour between turns.

Gotchas

• Conversation accumulates. Each turn's input-token count grows because the full history is replayed to the backend. Stop and restart the ensemble to reset the session. (E.stop("solo") followed by re-declaring in config or E.start_link/1 for ad hoc.)
• One in-flight turn at a time. A second tell while a turn is processing is queued in GenAgent's mailbox and runs after the first completes, not in parallel. Use Pool if you want parallelism.