AgentSPEX: An Agent SPecification and EXecution Language

A declarative workflow language for LLM-agent pipelines with explicit control flow, modular structure, and a customizable execution harness.

This is the official implementation accompanying the paper AgentSPEX: An Agent SPecification and EXecution Language. Visit the official website at agentspex.ai to try free demos.

See the Workflow Language Guide for full syntax, step types, and examples.

Quick start

1. Install dependencies

Create a conda environment and install the package:

conda create -n agentspex python=3.11 -y
conda activate agentspex
pip install -r requirements.txt
pip install -e .

2. Set up API keys

cp example.env .env

3. Quickstart

Run:

agentspex

Arrow-key navigation lets you run workflows, write task plans, browse docs, manage integrations, and control the sandbox VM — all without remembering CLI flags.

Or run directly:

agentspex run workflows/quickstart.yaml
agentspex run workflows/quickstart.yaml --model claude-opus-4-6
agentspex run --help

Each agentspex run spins up an isolated container for the duration of the workflow and tears it down on exit.

For repeated runs or a persistent VM:

docker build -t agentspex-sandbox:latest -f config/Dockerfile .
bash ./scripts/run_vm.sh start
bash ./scripts/run_agent.sh workflows/quickstart.yaml

Default VNC and MCP endpoints are printed on start. Stop with bash ./scripts/run_vm.sh stop.

Writing workflows

Workflows are YAML files that define a sequence of steps. A minimal example:

name: "hello_world"
goal: "A simple task to demonstrate the basics"

workflow:
  - step:
      name: "greet"
      instruction: "Say hello in a friendly way"

Workflows support parameters, template variables, loops, conditionals, parallel execution, sub-workflows, and more. See the Workflow Language Guide for the complete reference. Example workflows are in workflows/.

Where runs land

Every run — whether via agentspex, agentspex run, agentspex cli, or bash scripts/run_agent.sh — writes all logs, checkpoints, traces, step outputs, and reproducibility snapshots to:

workspace_persistent/outputs/<task_name>_<YYYYMMDD-HHMMSS>/

workspace/ is the host directory mounted as /workspace inside the container; it holds the agent's live working files. workspace_persistent/ is host-only and gitignored. Paths are derived from the project root, so the default works from any cwd without extra setup. Re-running the same workflow creates a new timestamped directory; --resume picks up the most recent one.

Writing a run-scoped workflow

Before parsing any workflow YAML, the harness exports these env vars:

Reference them directly in YAML so each run gets its own dir:

parameters:
  output_dir: "${AGENTSPEX_RUN_SANDBOX_DIR_ABS}"
  memory_file: "${AGENTSPEX_RUN_SANDBOX_DIR_ABS}/memory.json"

This makes memory files, downloaded artifacts, and any run-specific outputs land inside the same timestamped directory as the logs and checkpoints — no .env file required.

Options

Custom output directory

agentspex run workflows/quickstart.yaml --output_dir /path/to/output
# or with the persistent VM:
bash ./scripts/run_agent.sh workflows/quickstart.yaml --output_dir /path/to/output

Resume from checkpoint

agentspex run workflows/quickstart.yaml --resume

Replay from trace (no real tool calls)

bash ./scripts/run_agent.sh workflows/quickstart.yaml --replay_trace /path/to/trace.jsonl

Live dashboard

The agent streams structured events to a live dashboard that opens automatically when using run_agent.sh. To open it manually against any event log:

python scripts/dashboard.py /path/to/agent_events.log

Options: --port 5050, --host 127.0.0.1, --no-browser, --no-auto-close.

Sandbox VM

The sandbox VM provides the tools that workflows interact with. Source code is in src/sandbox_vm/.

Adding custom tools

1. Add tool functions under src/sandbox_vm/tools/
2. Register in src/sandbox_vm/tools/mcp_server_tool_config.yaml
3. Public functions (not _-prefixed) are auto-registered as MCP tools

Environment variables

Set in config/vm.env. $HOST_WORKSPACE is mounted at $VM_WORKSPACE inside the VM.

Project structure

workflows/           Workflow definitions (YAML)
src/harness/         Workflow execution engine
src/sandbox_vm/      Sandbox VM and MCP server
src/mcp_client/      MCP client library
docs/                Documentation
scripts/             Shell scripts and dashboard
config/              Environment and Docker configuration

License

The code included in this project is licensed under the Apache 2.0 license.