Daemon — Warm Runtime

praisonai daemon keeps provider clients, MCP connections, and agents hot in memory — repeated praisonai run calls reuse the already-warm agent instead of paying cold-start costs every time.

Quick Start

Install PraisonAI

pip install praisonai

Start the warm runtime in the background

praisonai daemon start --background

Run prompts — they attach automatically

praisonai run "Hello"
praisonai run "What is the capital of France?"

No flag, no env var. When the daemon is running, praisonai run forwards to it automatically. Bare prompts (praisonai "Hello") route to run, so they reuse the same warm path.

Check status and stop when done

praisonai daemon status
praisonai daemon stop

How It Works

What is warm	What is rebuilt per call
Provider client (LiteLLM)	Prompt text
MCP connections	Output format (structured, stream, etc.)
Loaded agent config	Session/memory overrides
Tool registrations	Per-invocation flags (see below)

When `run` Falls Back to In-Process

praisonai run does not forward to the daemon when you use these flags. They are handled in-process instead:

Flag	Reason
`--session`, `--continue`, `--fork`	Session continuity requires stateful context
`--memory`	Memory backend must be initialized per-session
`--approval`	Approval backends need a live terminal or channel
`--tools`, `--toolset`	Per-invocation tool overrides change agent config
`--attach`	Live session tagging for multi-terminal observation
`--output json`, `--stream`	Structured output modes attach directly to the process
`--trace`, `--profile`	Tracing and profiling require direct process access

When any of these flags is set, run behaves exactly as if no daemon were running — fully backward compatible.

CLI Reference

`praisonai daemon start`

Start the warm runtime server.

praisonai daemon start

praisonai daemon start --background

praisonai daemon start --host 127.0.0.1 --port 8899 --model gpt-4o-mini --idle-timeout 3600

Option	Type	Default	Description
`--host`, `-h`	`str`	`127.0.0.1`	Loopback address to bind. Non-loopback addresses are rejected.
`--port`, `-p`	`int`	`0` (auto)	Port to bind. `0` picks a free port automatically.
`--model`, `-m`	`str`	`None`	Default model for warm agents. Inherits your configured default when unset.
`--idle-timeout`	`float`	`1800.0`	Seconds of inactivity before the daemon auto-shuts-down. `0` disables.
`--background`, `-b`	`bool`	`False`	Detach from the terminal and run in the background.

--background spawns python -m praisonai_code.runtime as a detached process. The wrapper shim python -m praisonai.runtime remains for full-stack installs. Foreground and background modes both work on a standalone pip install praisonai-code.

`praisonai daemon status`

praisonai daemon status

praisonai daemon status --json

Option	Type	Default	Description
`--json`	`bool`	`False`	Machine-readable JSON output.

`praisonai daemon stop`

praisonai daemon stop

Sends SIGTERM to the daemon process. If the lockfile is stale (PID reuse), cleans up the lockfile instead of killing a random process.

Version compatibility

The warm runtime records its package version in the lockfile. Thin clients (praisonai run, praisonai attach) require a matching major version before reusing the runtime — a stale daemon after upgrade is ignored and the CLI falls back to in-process execution (or attach exits with code 1). After upgrading PraisonAI:

praisonai daemon stop
praisonai daemon start --background

See Attach for streaming live session events from a second terminal.

Security

The daemon only binds to loopback (127.0.0.1). Any --host value that is not a loopback address is rejected at startup with exit code 1.

Protection	How
Loopback-only	`ipaddress.is_loopback` check at startup — non-loopback `--host` exits 1
Token auth	Bearer token generated at startup, stored in lockfile with `0600` permissions
PID-reuse safety	`daemon stop` pings before sending `SIGTERM`; stale lockfile is cleaned, not used to kill a random process
Concurrent prompt safety	Per-model lock serializes `/run` calls — concurrent prompts cannot corrupt agent state
Error isolation	Agent evicted from cache on failed `start()` — transient LLM errors don’t leave a half-consumed turn cached

Troubleshooting

Runtime descriptor is stale

The lockfile exists but the PID it points to is dead. This usually happens after a crash or force-kill.Fix: Run praisonai daemon stop — it detects the stale lockfile and cleans it up automatically. Then praisonai daemon start again.

Runtime did not report ready in time (--background)

The daemon started but did not write its lockfile within the timeout.Fix: Try starting in foreground mode first (praisonai daemon start) to see error output. Common causes: port already in use, missing credentials, MCP server refusing connection.

praisonai run still feels slow

Verify the daemon is actually running and being detected:

praisonai daemon status --json

If the daemon is running but run is still in-process, you may be using a flag that forces in-process execution (see the fallback table above).

daemon start --background exits immediately

On some systems, background detach requires a clean environment. Try:

nohup praisonai daemon start > ~/.praisonai/daemon.log 2>&1 &

Models

Default model resolution — which model the daemon uses when none is specified

MCP

MCP handshake is the biggest cold-start cost that the daemon eliminates

Session Resume

For stateful multi-turn continuity (not forwarded to daemon)

CLI Reference

Full CLI flag reference

Attach

Stream live session events from another terminal

​Quick Start

​How It Works

​When run Falls Back to In-Process

​CLI Reference

​praisonai daemon start

​praisonai daemon status

​praisonai daemon stop

​Version compatibility

​Security

​Troubleshooting

​Related

Models

MCP

Session Resume

CLI Reference

Attach

Quick Start

How It Works

When `run` Falls Back to In-Process

CLI Reference

`praisonai daemon start`

`praisonai daemon status`

`praisonai daemon stop`

Version compatibility

Security

Troubleshooting

Related