LAO — Local AI Workflow Orchestrator

LAO is a headless engine and CLI for chaining local plugins into DAG-based workflows. Plugins are dynamically loaded shared libraries built against a small, stable C ABI; workflows are plain YAML. Everything runs locally and offline.

What it does

• Loads plugins at runtime by dlopen-ing shared libraries (.so/.dylib/.dll) that export a known C vtable.
• Parses a YAML workflow into a DAG, validates it (plugin availability + I/O type compatibility), topologically sorts it, and executes it.
• Supports parallel execution by dependency level, per-step retries with backoff, on-disk output caching, output-based conditions, and for_each loops.

YAML workflow → build_dag → topo_sort → PluginRegistry (dlopen) → run each step

See docs/architecture.md for internals.

Build

# Engine + CLI
cargo build --release

# Plugins (built in-place; the registry discovers them from each
# plugin's target/release/ or from the plugins/ directory)
bash scripts/build-plugins.sh

Quick start

# List the plugins the registry can load
./target/release/lao-cli plugin-list

# Validate, then run a workflow
./target/release/lao-cli validate workflows/test_loop.yaml
./target/release/lao-cli run workflows/test_loop.yaml

A workflow is a list of steps. Steps are ordered by their data/dependency edges; a step references an upstream step's output by its positional id (step1, step2, …):

workflow: "Audio Transcription & Summary"
steps:
  - run: WhisperPlugin          # step1
    input: "meeting.wav"
    cache_key: "whisper_transcription"
    retries: 2
    retry_delay: 1000

  - run: SummarizerPlugin       # step2
    input_from: step1           # receives step1's output as its input
    cache_key: "summary"

See docs/workflows.md for the full schema (conditions, loops, parallel levels, caching) and docs/cli.md for all commands.

Bundled plugins

Plugin	Purpose
EchoPlugin	Returns its input; reference implementation of the ABI
WhisperPlugin	Transcribes audio by shelling out to a local whisper.cpp build
SummarizerPlugin	Summarizes text via a local HTTP inference endpoint
PromptDispatcherPlugin	Generates a workflow YAML from a natural-language prompt
FileReadPlugin	Reads a file from disk and returns its contents
FolderMapPlugin	Recursively lists files under a directory
JsonExtractPlugin	Extracts a value from JSON via a $.a.b[0] selector
RegexExtractPlugin	Returns regex matches from text (first input line is the pattern)
ShellCommandPlugin	Runs a trusted shell command (gated by LAO_ALLOW_SHELL=1)
MarkdownReportPlugin	Formats text into a Markdown report, optionally writing it to disk

Writing your own plugin is a matter of implementing the C vtable — see lao_plugin_api, docs/plugin-api.md, and the bundled plugins for examples.

Configuration

Variable	Meaning
LAO_PLUGINS_DIR	Directory the registry scans for plugins (default: plugins/)
LAO_CACHE_DIR	Directory for cached step outputs (default: cache/)
RUST_LOG	Logging filter for CLI/core diagnostics (default: warn)
WHISPER_CPP_PATH	Path to the whisper.cpp build used by WhisperPlugin
LAO_ALLOW_SHELL	Compatibility escape hatch for trusted shell workflows

Production trust policy is configured through lao.toml:

[trust]
allow_filesystem_read = false
allow_filesystem_write = false
allow_filesystem_enumerate = false
allow_shell = false
allow_network = false
allow_subprocess = false
allow_plugins = []

Notes & limitations

• Plugins run in-process with full host privileges. The core trust policy denies dangerous capabilities by default, but trusted allowed plugins still run with host process privileges.
• Step success is determined by convention: a step is considered failed if its output is empty or begins with error:. The ABI has no separate status channel.
• Scheduling is persistent and manually triggered. schedule, unschedule, list-scheduled, and run-due operate on persisted state. There is no background daemon.

License

Apache-2.0 — see LICENSE.