YAML Reference

Flow files are stored as YAML in ~/.config/astonish/flows/.

Basic Structure

description: "What this flow does"
nodes:
  - name: "step1"
    type: "input"
    prompt: "Enter your name"
    output_model:
      user_name: "string"
  - name: "step2"
    type: "llm"
    prompt: "Greet {{user_name}}"
    system: "You are a friendly assistant"
    tools: true
  - name: "step3"
    type: "output"
    value: "{{step2_output}}"
flow:
  - from: "START"
    to: "step1"
  - from: "step1"
    to: "step2"
  - from: "step2"
    to: "step3"
  - from: "step3"
    to: "END"

Node Types

Type	Purpose	Key Fields
input	Collect user input	prompt, output_model, options
llm	Send prompt to AI model	prompt, system, tools, tools_selection, tools_auto_approval
tool	Execute a specific tool	action, args, raw_tool_output
output	Display results	value
update_state	Modify state variables	updates

Node Properties

Property	Type	Description
name	string	Unique node identifier
type	string	Node type (see above)
prompt	string	Prompt text (supports {{variable}} interpolation)
system	string	System prompt for LLM nodes
tools	bool	Enable tool use on LLM nodes
tools_selection	string[]	Restrict to specific tools
output_model	object	Define output variables (key: type pairs)
args	object	Tool arguments for tool nodes
continue_on_error	bool	Don’t stop on failure
max_retries	int	Retry count (default: 3)
retry_strategy	string	intelligent or simple
silent	bool	Suppress output
parallel	object	Parallel execution: forEach, as, index_as, maxConcurrency
output_action	string	How to aggregate parallel output (append)

Edge Properties

Edges are defined in the flow section of the YAML.

Property	Type	Description
from	string	Source node name (or "START")
to	string	Target node name (or "END")
edges	array	Conditional edges: {to, condition}

Conditional edges use the condition field with expressions that reference state variables. See Nodes, Edges & State for examples.

MCP Dependencies

Flows can declare MCP server dependencies that get auto-installed when the flow is run:

mcp_dependencies:
  - server: "github"
    tools: ["create_issue", "list_repos"]
    source: "store"
    store_id: "github-mcp"