Sagents.AgentSupervisor (Sagents v0.8.0-rc.4)

Custom supervisor for managing an Agent and its supporting infrastructure.

AgentSupervisor coordinates the lifecycle of:

AgentServer - Agent execution and state management
SubAgentsDynamicSupervisor - Dynamic supervisor for spawning sub-agents

Supervision Strategy

Uses :rest_for_one strategy to ensure crash resilience:

If AgentServer crashes, SubAgentsDynamicSupervisor restarts
SubAgentsDynamicSupervisor crashes only affect itself

Filesystem Integration

Filesystems are now managed independently via FileSystemSupervisor. Agents reference filesystems through the filesystem_scope field in the Agent struct. See Sagents.FileSystem for filesystem lifecycle management.

Configuration

Accepts a keyword list with:

:agent - The Agent struct (required)
:initial_state - Initial State for AgentServer (optional)
:pubsub - PubSub configuration as {module(), atom()} tuple or nil (optional, default: nil)
:shutdown_delay - Delay in milliseconds to allow the supervisor to gracefully stop all children (optional, default: 5000)
:conversation_id - Optional conversation identifier for message persistence (optional, default: nil)
:agent_persistence - Module implementing Sagents.AgentPersistence (optional, default: nil)
:display_message_persistence - Module implementing Sagents.DisplayMessagePersistence (optional, default: nil)

Examples

# Minimal configuration
{:ok, agent} = Agent.new(
  agent_id: "my-agent",
  model: model,
  base_system_prompt: "You are a helpful assistant."
)

{:ok, sup_pid} = AgentSupervisor.start_link(agent: agent)

# With initial state and PubSub
initial_state = State.new!(%{
  messages: [Message.new_user!("Hello!")]
})

{:ok, sup_pid} = AgentSupervisor.start_link(
  agent: agent,
  initial_state: initial_state,
  pubsub: {Phoenix.PubSub, :my_app_pubsub}
)

# With external filesystem
# Start filesystem separately
{:ok, config} = FileSystemConfig.new(%{
  scope_key: {:user, 123},
  base_directory: "Memories",
  persistence_module: Sagents.FileSystem.Persistence.Disk,
  storage_opts: [path: "/data/users/123"]
})
{:ok, _fs_pid} = FileSystem.ensure_filesystem({:user, 123}, [config])

# Create agent with filesystem reference
{:ok, agent} = Agent.new(%{
  agent_id: "my-agent",
  model: model,
  filesystem_scope: {:user, 123}
})

{:ok, sup_pid} = AgentSupervisor.start_link(agent: agent)

Summary

Functions

child_spec(init_arg)

Returns a specification to start this module under a supervisor.

get_name(agent_id)

Get the name of the AgentSupervisor process for a specific agent.

get_pid(agent_id)

Get the PID of an AgentSupervisor by agent_id.

start_link(config)

Start the AgentSupervisor.

start_link_sync(config)

Start the AgentSupervisor and wait for the AgentServer to be ready.

stop(agent_id, timeout \\ 5000)

Stop the AgentSupervisor.

Functions

child_spec(init_arg)

Returns a specification to start this module under a supervisor.

See Supervisor.

get_name(agent_id)

@spec get_name(String.t()) :: GenServer.name()

Get the name of the AgentSupervisor process for a specific agent.

Examples

name = AgentSupervisor.get_name("my-agent-1")
AgentSupervisor.stop(name)

get_pid(agent_id)

@spec get_pid(String.t()) :: {:ok, pid()} | {:error, :not_found}

Get the PID of an AgentSupervisor by agent_id.

Examples

{:ok, pid} = AgentSupervisor.get_pid("my-agent-1")
{:error, :not_found} = AgentSupervisor.get_pid("non-existent")

start_link(config)

@spec start_link(keyword()) :: Supervisor.on_start()

Start the AgentSupervisor.

Options

:agent - The Agent struct (required)
:initial_state - Initial State for AgentServer (optional)
:pubsub - PubSub configuration as {module(), atom()} tuple or nil (optional, default: nil). Used only for Phoenix.Presence presence_diff wiring; per-agent events are delivered directly to subscriber pids via Sagents.Publisher.
:inactivity_timeout - Timeout in milliseconds for automatic shutdown (optional, default: 300_000 - 5 minutes) Set to nil or :infinity to disable automatic shutdown
:name - Supervisor name registration (optional)
:shutdown_delay - Delay in milliseconds to allow the supervisor to gracefully stop all children (optional, default: 5000)
:conversation_id - Optional conversation identifier for message persistence (optional, default: nil)
:agent_persistence - Module implementing Sagents.AgentPersistence (optional, default: nil)
:display_message_persistence - Module implementing Sagents.DisplayMessagePersistence (optional, default: nil)

Examples

{:ok, sup_pid} = AgentSupervisor.start_link(
  agent: agent,
  pubsub: {Phoenix.PubSub, :my_app_pubsub}
)

{:ok, sup_pid} = AgentSupervisor.start_link(
  agent: agent,
  name: AgentSupervisor.get_name("agent-123")
)

# With custom inactivity timeout
{:ok, sup_pid} = AgentSupervisor.start_link(
  agent: agent,
  inactivity_timeout: 600_000  # 10 minutes
)

# Disable automatic shutdown
{:ok, sup_pid} = AgentSupervisor.start_link(
  agent: agent,
  inactivity_timeout: nil
)

start_link_sync(config)

@spec start_link_sync(keyword()) :: {:ok, pid()} | {:error, term()}

Start the AgentSupervisor and wait for the AgentServer to be ready.

This is a synchronous version of start_link/1 that waits for the AgentServer child process to be fully registered before returning. This prevents race conditions where callers try to interact with the AgentServer (e.g., subscribe, add_message) before it's ready.

Why This Is Needed

When start_link/1 returns successfully, the supervisor is running but its children are still completing their initialization asynchronously. If you immediately try to call AgentServer.get_pid/1 or AgentServer.subscribe/1, the AgentServer might not be registered yet, causing failures.

This function solves that by:

Starting the supervisor normally
Polling for the AgentServer to be registered with exponential backoff
Returning only when the AgentServer is confirmed ready

Use Cases

Use this function when you need immediate access to the AgentServer:

Web request handlers that need to subscribe or send messages right away
CLI tools that need synchronous agent startup
Test setups that require the agent to be fully ready

Use regular start_link/1 when:

Startup timing isn't critical
You can handle eventual consistency
You're starting many agents in parallel

Options

Same as start_link/1, plus:

:startup_timeout - Maximum time to wait for AgentServer readiness (default: 5000ms)

Examples

# Start and wait for agent to be ready
{:ok, sup_pid} = AgentSupervisor.start_link_sync(
  agent: agent,
  pubsub: {Phoenix.PubSub, :my_app_pubsub}
)

# Agent is guaranteed to be ready - safe to use immediately
:ok = AgentServer.subscribe(agent.agent_id)

# Custom startup timeout
{:ok, sup_pid} = AgentSupervisor.start_link_sync(
  agent: agent,
  startup_timeout: 10_000
)

Returns

{:ok, supervisor_pid} - Supervisor started and AgentServer is ready
{:error, {:agent_startup_timeout, agent_id}} - AgentServer failed to become ready
{:error, reason} - Supervisor failed to start

stop(agent_id, timeout \\ 5000)

@spec stop(String.t(), timeout()) :: :ok | {:error, :not_found}

Stop the AgentSupervisor.

Examples

AgentSupervisor.stop("my-agent-1")
AgentSupervisor.stop("my-agent-1", 10_000) # 10 second timeout