Beddel

Declarative YAML workflow engine for AI pipelines — run multi-step LLM chains with branching, guardrails, retry, and observability out of the box.

Prerequisites

• Python 3.11+ (python3.11 --version)
• pip for Python 3.11 (python3.11 -m pip --version)
• An LLM API key — any LiteLLM-supported provider works. Gemini recommended:

export GEMINI_API_KEY="your-key"

Installation

python3.11 -m pip install "beddel[all]"
beddel version

Note: System Python may be 3.10. Always use python3.11 explicitly.

Quick Start

1. Write a workflow file hello.yaml:

id: hello
name: Hello World
input_schema:
  topic: { type: str, required: true }
steps:
  - id: greet
    primitive: llm
    config:
      model: gemini/gemini-2.0-flash
      prompt: "Write a one-sentence greeting about $input.topic"
      max_tokens: 50

2. Run it:

beddel run hello.yaml -i topic="AI agents" --json-output

Tool Integration (OpenClaw Plugin)

The beddel tool is available via the OpenClaw plugin @botanarede/beddel:

openclaw plugins install @botanarede/beddel

Once installed, the agent can invoke beddel with actions: run, validate, list-primitives.

The bundled example examples/setup-beddel.yaml automates this installation — see Bundled Example below.

CLI Reference

Core Concepts

A workflow is a YAML file with an id, name, optional input_schema, and a list of steps. Each step declares a primitive (the unit of work) and a config (primitive-specific parameters).

Steps execute sequentially. Each step's output is available to subsequent steps via $stepResult.<step_id>.<path>.

See references/ for full schema documentation.

Primitives

Execution Strategies

Each step can declare an execution_strategy to control error handling:

Variable Resolution

Key paths for step results:

• tool steps: $stepResult.<id>.result.stdout, .result.exit_code
• llm steps: $stepResult.<id>.content
• guardrail steps: $stepResult.<id>.data.<field>, .valid

Bundled Example: setup-beddel

This workflow checks whether the @botanarede/beddel OpenClaw plugin is installed and installs it if needed. It demonstrates 3 of the 7 primitives: tool, guardrail, and conditional execution via if.

id: setup-beddel
name: Beddel Plugin Setup
description: Install or update the @botanarede/beddel OpenClaw plugin and verify it loads.

steps:
  - id: check_plugin
    primitive: tool
    config:
      tool: shell_exec
      arguments:
        cmd: "python3.11 -c \"import subprocess,json,re;r=subprocess.run(['openclaw','plugins','list'],capture_output=True,text=True);has=bool(re.search(r'beddel',r.stdout));loaded=bool(re.search(r'beddel.*loaded',r.stdout));print(json.dumps({'action':'OK'if loaded else'REINSTALL'if has else'INSTALL'}))\""

  - id: validate_check
    primitive: guardrail
    config:
      data: "$stepResult.check_plugin.result.stdout"
      schema:
        fields:
          action: { type: str, required: true }
      strategy: correct

  - id: install_plugin
    primitive: tool
    config:
      tool: shell_exec
      arguments:
        cmd: "openclaw plugins install @botanarede/beddel"
      timeout: 120
    if: "$stepResult.validate_check.data.action != 'OK'"

  - id: verify
    primitive: tool
    config:
      tool: shell_exec
      arguments:
        cmd: "openclaw plugins info beddel"

What each step demonstrates

Run it:

beddel run examples/setup-beddel.yaml --json-output

Security & Privacy

• Secrets: Use $env.* variables — never hardcode API keys in workflow YAML
• shell_exec: Runs with shell=False (no shell injection). Commands are split via shlex.split(). Shell operators (|, &&, >) are sanitized in beddel 0.1.1+
• Subprocess sandbox: Default timeout 60s, max stdout 1MB per stream, configurable per step

External Endpoints

Trust Statement

Beddel executes user-defined YAML workflows. It does not phone home, collect telemetry by default, or transmit data beyond the configured LLM provider endpoints. OpenTelemetry export is opt-in.

Observability

Beddel emits OpenTelemetry spans for every workflow and step execution:

• beddel.workflow.execute — root span per workflow run
• beddel.step.<primitive> — child span per step
• gen_ai.usage.* attributes on LLM steps (prompt/completion tokens)

Enable with any OTel-compatible collector via standard OTEL_* environment variables.

Troubleshooting

Advanced: Python SDK

from beddel import WorkflowExecutor, VariableResolver

resolver = VariableResolver()
resolver.register_namespace("secrets", lambda path, ctx: get_secret(path))

executor = WorkflowExecutor(resolver=resolver)
result = await executor.execute(workflow, {"topic": "AI"})

For FastAPI integration: beddel serve -w workflow.yaml --port 8000

References

Additional documentation in references/ (loaded on demand):

• workflow-format.md — Complete YAML schema
• primitives.md — All 7 primitives with full config options
• execution-strategies.md — 5 strategies with examples
• variable-resolution.md — Namespaces, custom resolvers, error handling