build-script

name	build-script
description	Use when the user wants to write, test, or deploy an ArchAstro script — custom logic for agent tools, workflow nodes, and routines. Trigger phrases include "build a script", "write a script", "create a script", "test a script", "script syntax", "script reference", "script language".
allowed-tools	["Bash(archastro:*)"]

ArchAstro Script Builder

Write, test, and deploy scripts — custom logic that powers agent tools, workflow nodes, and routines.

This skill assumes the ArchAstro CLI is already installed and authenticated. Use the /archastro:install and /archastro:auth commands in this same plugin instead of trying to install or authenticate the CLI manually inside this skill.

What is a Script?

Scripts are expression-oriented custom logic written in the ArchAstro script language. They can be used as:

• Custom tool handlers: Agent calls a tool → script runs → result returned to agent
• Workflow graph script steps: Script logic used inside a workflow graph
• Routine handlers: A scheduled routine runs the script directly

Scripts are first-class resources with their own CRUD, validation, and execution commands. Use the dedicated top-level script resource for the normal authoring loop: archastro list scripts, describe script, create script, update script, validate script, run script, and describe scriptdocs.

Always Start with State

Every invocation must begin by understanding the current context:

archastro auth status
archastro list scripts

Determine:

• Is the user creating a new script or editing an existing one?
• What will this script be used for? (tool, workflow node, routine)
• What external APIs or data does it need to access?

Routing

CLI not installed or too old

Before any script work, verify the CLI:

• Read plugin-compatibility.json from the plugin root.
• Prefer plugins.archastro.minimumCliVersion, fall back to the top-level minimumCliVersion.
• Run archastro --version. If missing or older than the resolved minimum, direct the user to /archastro:install.
• If authentication or app selection is missing, direct the user to /archastro:auth.

User wants to write a new script

Phase 1: Get the language reference

Always start by fetching the live reference — do not write scripts from memory:

archastro describe scriptdocs

Use the top-level script commands, not describe configsample/validate config, for the normal authoring loop.

Create a script from a local source file:

archastro create script --id my-script --file ./scripts/my-script.agentscript

Or let the CLI start from its built-in sample if you do not pass --source or --file:

archastro create script --id my-script

Phase 2: Understand the requirements

Ask the user:

• What should the script do?
• What inputs will it receive? (accessible via $ JSONPath)
• Does it need environment variables? (accessible via env.KEY)
• Does it need to make HTTP calls?

If the script will handle a routine event, discover what $ contains by checking the event's payload schema:

archastro list events
archastro describe event <event-name>

describe event returns the JSON schema and a sample payload. Every field in the payload is accessible via $ in the script (e.g., $.thread_id, $.message.content). Always check the event schema before writing scripts that consume routine payloads — do not guess the shape from memory.

Phase 3: Author the script

Key language concepts:

• Input: Access via $ (JSONPath). E.g., $.order_id, $.user.email
• Environment: Access via env.KEY. E.g., env.API_TOKEN
• Imports: import("requests"), import("array"), import("string"), etc.
• Error handling: unwrap(result) or unwrap(result, default_value)
• No loops: Use array.map, array.filter, array.reduce
• Expression-oriented: The last expression in the script is the return value
• Debugging: Use println() to inspect values

Example — HTTP lookup script:

let http = import("requests")
let arr = import("array")

let response = http.get(env.API_URL + "/orders/" + $.order_id, {
  headers: { "Authorization": "Bearer " + env.API_TOKEN }
})
let body = unwrap(response)

{
  order_id: $.order_id,
  status: body.status,
  items: arr.map(body.line_items, fn(item) {
    { name: item.name, qty: item.quantity }
  })
}

Available namespaces:

• requests — HTTP client (get, post, put, patch, delete)
• array — Collection operations (map, filter, reduce, find, sort, flat_map)
• string — String operations (split, join, trim, lowercase, uppercase, contains)
• map — Object operations (keys, values, merge, get)
• datetime — Date/time operations (now, format, parse, add)
• math — Math operations (round, floor, ceil, abs)
• result — Result type operations (ok, err, is_ok, is_err)
• email — Email sending
• jwt — JWT token operations
• slack — Slack API operations

Phase 4: Validate

Validate the script syntax:

archastro validate script --file ./scripts/my-script.agentscript

Or validate as a config:

archastro validate config -k Script -f ./configs/scripts/my-script.yaml

Fix any validation errors before proceeding.

Phase 5: Test

Run the script locally with test input:

archastro run script --file ./scripts/my-script.agentscript --input '{"order_id": "ORD-123"}'

For scripts that need env vars, ensure they are set on the platform:

archastro list orgenvvars
archastro create orgenvvar -k API_TOKEN -v "sk-..."

Phase 6: Deploy

Scripts can be deployed two ways:

As a standalone script resource:

archastro create script --id order-lookup -n "Order Lookup" --file ./scripts/my-script.agentscript

Update an existing script resource:

archastro update script order-lookup --file ./scripts/my-script.agentscript

Via deploy configs (for config-managed repos):

Place .agentscript files in configs/scripts/ and deploy:

archastro deploy configs

The scripts/ directory enforces that only .agentscript files and .yaml/.json with kind: Script are allowed — other file types are rejected. See the manage-configs skill for setting up the configs directory.

Phase 7: Wire it up

Connect the script to where it will be used:

As a custom tool on an agent:

The API requires --config-id pointing at the script's config ID even for script-handler tools:

archastro create agenttool --agent <agent-id> \
  --kind custom \
  --name "lookup_order" \
  --description "Look up an order by ID" \
  --handler-type script \
  --config-id <script-config-id> \
  --instruction "Use this tool when the user asks to look up an order." \
  --parameters '{"type":"object","properties":{"order_id":{"type":"string"}},"required":["order_id"]}'

Get the script's config ID from archastro describe script <id> --output json (the configId field).

In a workflow graph: Follow the real WorkflowGraph shape from archastro describe workflowdocs and the build-workflow skill.

As a routine handler (reference by config ID — preferred for production):

archastro create agentroutine --agent <agent-id> \
  --name "My scheduled script" \
  --event-type schedule.cron \
  --schedule "0 9 * * 1-5" \
  --handler-type script \
  --config-id <script-config-id>

Get the script's config ID from archastro describe script <id> --output json (the configId field).

Or inline for quick prototyping:

archastro create agentroutine --agent <agent-id> \
  --name "Quick test" \
  --event-type schedule.cron \
  --schedule "0 9 * * 1-5" \
  --handler-type script \
  --script 'println("hello")'

Prefer --config-id for production — it keeps the routine linked to a versioned script resource that can be updated independently.

User wants to edit an existing script

1. Inspect the current script:

   archastro list scripts
   archastro describe script <id>
   

2. Edit locally, validate, and update:

   archastro validate script --file ./scripts/my-script.agentscript
   archastro update script <id> --file ./scripts/my-script.agentscript
   

Common Mistakes

Do not write JSON — use script object syntax:

// WRONG — JSON syntax causes "unexpected token :" errors
{ "status": "ok", "count": 5 }

// CORRECT — script uses unquoted keys
{ status: "ok", count: 5 }

Do not use return — the last expression is the return value:

// WRONG
return { status: "ok" }

// CORRECT
{ status: "ok" }

Always import namespaces before using them:

// WRONG — "Unknown identifier" error
let now = datetime.now()

// CORRECT
let dt = import("datetime")
let now = dt.now()

No imperative loops — use array functions:

// WRONG — for/while don't exist
for item in items { ... }

// CORRECT
let arr = import("array")
arr.map(items, fn(item) { ... })

Script Authoring Rules

• Always fetch archastro describe scriptdocs before writing scripts. Do not invent syntax from memory.
• Prefer the dedicated top-level script commands over the generic configs resource unless the user explicitly wants config-managed files.
• Treat the language as functional and expression-oriented, not imperative.
• The last expression is the return value — there is no return keyword.
• Use unwrap() for error handling — never assume HTTP calls succeed.
• Use println() liberally while debugging, remove before deploying.
• If validation fails, rewrite toward the sample/reference instead of trial-and-error.

Recovery Rules

• If a script fails validation, show the exact error. Common issues: missing imports, wrong function signatures, trying to use imperative loops.
• If archastro run script fails at runtime, check: are env vars set? Is the input JSON valid? Is the API reachable?
• If the user is unsure about syntax, always fall back to archastro describe scriptdocs.

Response Rules

• Do not inspect or edit credential files directly — use the CLI only.
• Do not ask the user to pick raw subcommands when intent is clear.
• Keep responses concise and operational.
• Show the user a concrete script draft they can review, not abstract syntax explanations.