agent-composer

Agent Compose

Deterministic workflows of agents. Agent Compose is a small engine for composing LLM agents, plain Python code, ML models, and tools into a single runnable flow, described in a Docker-Compose-shaped YAML file. You decide the structure; the LLMs fill the leaf boxes.

A flow is a function: it has typed input:, a graph of nodes:, and an output:. The graph between nodes is inferred from the ${...} references — you never draw edges by hand.

# hello.yaml
id: hello
name: hello
input:
  name: str
nodes:
  greet:
    kind: agent
    input:
      name: ${input.name}
    output: str
    prompt: |-
      Write a short, warm one-sentence greeting addressed to ${name}.
output: ${greet.output}

$ ac run hello.yaml --input name=Ada
Hello, Ada — it's wonderful to have you here!

Install

pip install agent-composer

Provider SDKs are optional extras — install the one(s) you use:

pip install "agent-composer[anthropic]"   # Claude
pip install "agent-composer[openai]"      # GPT
pip install "agent-composer[google]"      # Gemini
pip install "agent-composer[ollama]"      # local models
pip install "agent-composer[all]"         # everything

The core (engine + CLI) installs with no provider SDK; importing a provider you haven't installed raises a clear pip install agent-composer[...] hint.

The ac CLI

ac run FLOW.yaml [--input k=v]... [--inputs inputs.json] [--quiet]

• --input k=v — set one input (repeatable). Values are coerced to each input's declared type.
• --inputs file.json — load inputs from a JSON object. --input flags override individual keys.
• Any required input still missing is prompted interactively.
• A flow that suspends on a HUMAN_INPUT / WAIT node is resumed interactively — each pause prompts for the awaited value and the run continues to completion.

Choosing a provider/model

The default provider and model are read from the environment:

export AGENT_COMPOSE_DEFAULT_PROVIDER=anthropic        # or openai / google / ollama
export AGENT_COMPOSE_DEFAULT_MODEL=claude-sonnet-4-5
export ANTHROPIC_API_KEY=...                            # provider's own key var

For a local Ollama endpoint:

export AGENT_COMPOSE_DEFAULT_PROVIDER=ollama
export AGENT_COMPOSE_DEFAULT_MODEL=llama3.2:3b
export OLLAMA_BASE_URL=http://localhost:11434
ac run examples/hello.yaml --input name=Ada

Examples

The examples/ directory ships a few generic flows:

• hello.yaml — the smallest agent flow (one AGENT, string in/out).
• summarize.yaml — condense a block of text into one sentence.
• classify.yaml — label text with a constrained Literal[...] output.

Use it as a library

from agent_compose import load_flow, run_flow

loaded = load_flow(open("hello.yaml").read(), search_paths=["."])
result = run_flow(loaded, {"name": "Ada"})
print(result.status, result.output)

Develop & test

pip install -e ".[all,dev]"
pytest

Publish

Releases are published to PyPI automatically by GitHub Actions (.github/workflows/publish.yml) whenever a GitHub Release is published. It uses PyPI Trusted Publishing (OIDC), so no API token or secret is stored in the repo.

One-time PyPI setup (https://pypi.org/manage/account/publishing/ → "Add a pending publisher"):

To cut a release:

1. Bump version in pyproject.toml, commit, and push to main.
2. Tag and create a GitHub Release (e.g. v0.0.2) — the publish job builds, tests, and uploads to PyPI.

Manual publish (fallback, needs an account-scoped API token):

pip install build twine
python -m build            # wheel + sdist into dist/
twine upload dist/*        # TWINE_USERNAME=__token__  TWINE_PASSWORD=pypi-...

License

Apache 2.0 — see LICENSE.