Session Persistence

Appam exposes two related pieces here:

AgentBuilder history settings, which the runtime uses for run() and continue_session()
SessionHistory, which gives you manual listing, loading, deletion, and retention control

Enable History on the Agent

If you want continue_session() to work, the agent itself must be configured with history enabled:

use appam::prelude::*;

let agent = AgentBuilder::new("my-agent")
    .provider(LlmProvider::OpenAI)
    .model("gpt-5.4")
    .system_prompt("You are a helpful assistant.")
    .enable_history()
    .history_db_path("data/sessions.db")
    .auto_save_sessions(true)
    .build()?;

The same settings can also live in global config:

[history]
enabled = true
db_path = "data/sessions.db"
auto_save = true
max_sessions = 100

Continue a Session

let first = agent.run("What is Rust?").await?;

let second = agent
    .continue_session(&first.session_id, "How does ownership work?")
    .await?;

The runtime loads the prior session from the configured history database. A standalone SessionHistory instance does not automatically wire itself into continue_session() unless the agent points at the same database.

Manual SessionHistory Usage

Use SessionHistory when you need direct database operations:

use appam::prelude::*;

let mut config = HistoryConfig::default();
config.enabled = true;
config.db_path = "data/sessions.db".into();

let history = SessionHistory::new(config).await?;
let sessions = history.list_sessions().await?;

Common Operations

let loaded = history.load_session("session-id").await?;
let deleted = history.delete_session("session-id").await?;
let removed = history.enforce_max_sessions().await?;

Data Shapes

appam::agent::Session stores:

session_id
agent_name
model
messages
started_at
ended_at
usage

appam::agent::history::SessionSummary stores:

id
agent_name
model
message_count
turn_count
tool_call_count
started_at
updated_at
ended_at