arazzo-cli

Execute multi-step API workflows from a YAML spec — no code generation, no glue scripts.

arazzo-cli is a standalone executor for Arazzo, the OpenAPI Initiative's spec for describing sequences of API calls as declarative workflows. Define your steps, parameters, success criteria, and control flow in YAML, then run them directly from the command line or step through them in VS Code.

Why?

Testing a sequence of API calls today means writing imperative scripts, maintaining collections, or building custom test harnesses. The Arazzo spec (part of the OpenAPI ecosystem) lets you describe these sequences declaratively — but without a runtime, the spec is just documentation.

arazzo-cli makes Arazzo specs executable: validate them, run them, trace them, and debug them interactively.

Demo

Quick Start

git clone https://github.com/strefethen/arazzo-cli.git
cd arazzo-cli
cargo run -p arazzo-cli -- validate examples/httpbin-get.arazzo.yaml
cargo run -p arazzo-cli -- run examples/httpbin-get.arazzo.yaml get-origin

Or install it:

cargo install --path ./crates/arazzo-cli --locked
arazzo-cli validate examples/httpbin-get.arazzo.yaml
arazzo-cli run examples/httpbin-get.arazzo.yaml get-origin

Features

Feature	What it does
Run workflows	Execute HTTP steps, resolve expressions, evaluate success criteria, route control flow
Run single steps	Execute one step with automatic dependency resolution (--step)
Generate workflows	Scaffold CRUD workflows from OpenAPI 3.x specs (generate)
Validate specs	Parse and structurally validate Arazzo YAML before running
Parallel execution	Run independent steps concurrently with DAG-based scheduling (--parallel)
Dry-run mode	Resolve all requests without sending them (--dry-run)
Input validation	Type-check and require workflow inputs, with strict mode (--strict-inputs)
Execution traces	Write detailed trace.v1 JSON artifacts with automatic sensitive value redaction
Deterministic replay	Re-execute trace artifacts offline with response injection and drift checks (replay)
Sub-workflows	Call workflows from workflows with input/output passing (up to 10 levels deep)
VS Code debugger	Set breakpoints, step through workflows, inspect variables, evaluate expressions
JSON output	--json on every command for scripting and CI integration
Expression language	$inputs, $steps, $response, $env, XPath, JSON Pointer, interpolation
Arazzo 1.1 selectors	Typed JSONPath, JSON Pointer, and XPath Selector Objects across values and outputs
Success criteria	Simple expressions, regex, XPath, and JSONPath criterion types
Control flow	onSuccess/onFailure actions with goto, retry (with backoff), and end
Multiple API sources	Route steps to different APIs via sourceDescriptions
SOAP support	Execute SOAP workflows with XPath-based success criteria
Rate limiting	Built-in token-bucket rate limiter (10 req/sec default, configurable burst)
.env loading	Automatic .env file loading — reference secrets as $env.VAR_NAME
Reusable components	$ref to shared parameters, inputs, and action handlers via components
MCP server	Expose workflows as tools for AI agents via Model Context Protocol (serve), plus authoring