Runtime storage - Fused

Harnest keeps committed session state separate from private in-progress execution state. It discovers storage factories across root and Harnest Extension extension files, then assembles one typed registry. Every application resolves exactly one session store and one checkpointer, even when both roles share the same backend object.

Role	Holds	Agent access	Guide
Sessions	Committed conversation history and application session data	`context.session`	Sessions and application storage
Checkpoints	Active run state, framework snapshots, pending writes, and resumable waits	Framework-owned	Checkpoints
Tasks and cron	Queued work, results, leases, and recurring schedules	`harnest.task` / `harnest.cron`	Task and cron storage
Named assets	Session-owned media bytes	`context.assets("name")`	Store and retrieve media
Named custom storage	Domain repositories	`context.storage("name")`	Sessions and application storage

Reuse a backend without merging roles

Put a shared connection in lib/, then declare each responsibility in its own extension file:

lib/state.py
lifecycle/sessions.py
lifecycle/checkpoints.py

import os

from harnest.store import PostgresStore

state = PostgresStore(os.environ["DATABASE_URL"])

from harnest.lib.state import state
from harnest import lifecycle


@lifecycle.storage.sessions
def sessions():
    """Provide committed session and conversation storage."""

    return state

from harnest.lib.state import state
from harnest import lifecycle


@lifecycle.storage.checkpoints
def checkpoints():
    """Provide private in-progress execution storage."""

    return state

Harnest starts the shared object once and closes it once. Separate factories make ownership visible even when the physical backend is the same. If one small factory intentionally owns both roles, you can stack the two decorators.

Choose a backend

Store	Best for	Limitation
`MemoryStore`	Local development and tests	Process-local and lost on restart
`PostgresStore`	Durable sessions, checkpoints, and continuations	Requires PostgreSQL
`RedisStore`	Distributed sessions and expiring checkpoints	Durability depends on Redis configuration
Custom store	Existing infrastructure	You own schema, migration, and durability

Sessions and application storage

Configure conversation state, context.session, assets, and domain repositories.

Checkpoints

Configure active-run recovery, framework adapters, and replica safety.