Code Engine

Rule: Domo App Platform Code Engine (Toolkit-First)

Use a contract-first pattern for Code Engine calls. In practice, prefer direct domo.post('/domo/codeengine/v2/packages/{alias}', params) when wiring app calls.

Package lifecycle operations are handled by CLI skills:

• ~/.agents/skills/code-engine-create/SKILL.md
• ~/.agents/skills/code-engine-update/SKILL.md

Use this skill for runtime invocation patterns inside app code, not package create/update orchestration.

Working call pattern (domo.post)

npm install ryuu.js

import domo from 'ryuu.js';

const response = await domo.post('/domo/codeengine/v2/packages/calculateTax', {
  amount: 1000,
  state: 'CA'
});

Response parsing requirement

// First integration pass: inspect exact response shape for this function
console.log('Code Engine response:', response);

const body = response?.body ?? response?.data ?? response;

// Some package contracts return nested envelopes:
// { response: { ... } } or { response: { response: { ... } } }
const unwrapResponse = (value: unknown) => {
  let current = value as any;
  let depth = 0;
  while (current && typeof current === 'object' && 'response' in current && depth < 6) {
    current = current.response;
    depth += 1;
  }
  return current;
};
const normalized = unwrapResponse(body);

// Handle common output shapes
const output =
  normalized?.output ??
  normalized?.result ??
  normalized?.value ??
  normalized;

if (typeof output === 'number') {
  // numeric output
} else if (typeof output === 'string') {
  // string output
} else if (output && typeof output === 'object') {
  // structured object output
} else {
  throw new Error('Code Engine returned no usable output');
}

Manifest requirement: packagesMapping (with s)

Use packagesMapping and define full parameter/output contracts.

{
  "packagesMapping": [
    {
      "name": "myPackage",
      "alias": "myFunction",
      "packageId": "00000000-0000-0000-0000-000000000000",
      "version": "1.0.0",
      "functionName": "myFunction",
      "parameters": [
        {
          "name": "param1",
          "displayName": "param1",
          "type": "decimal",
          "value": null,
          "nullable": false,
          "isList": false,
          "children": [],
          "entitySubType": null,
          "alias": "param1"
        }
      ],
      "output": {
        "name": "result",
        "displayName": "result",
        "type": "number",
        "value": null,
        "nullable": false,
        "isList": false,
        "children": [],
        "entitySubType": null,
        "alias": "result"
      }
    }
  ]
}

Version pinning rule:

• If the user expects a fixed package build, set "version": "x.y.z" explicitly in each packagesMapping entry.
• Do not leave version as null unless the user explicitly wants unpinned/latest behavior.

Required contract disclosure to user

When recommending or generating Code Engine calls, the agent must explicitly tell the user:

• exact input parameter names, types, and nullable expectations
• expected output name, type, and shape (number/string/object)
• whether output is wrapped in a response envelope (and if nested envelopes are possible)

This is required so the user can build a matching Code Engine function and manifest contract.

Error Handling Pattern

async function executeFunction(alias: string, payload: Record<string, unknown>) {
  try {
    const response = await domo.post(`/domo/codeengine/v2/packages/${alias}`, payload);
    console.log('Code Engine response:', response);
    return response?.body ?? response?.data ?? response;
  } catch (error) {
    console.error(`Code Engine call failed for alias ${alias}`, error);
    throw error;
  }
}

Discovering function names on global Domo packages

When calling a Domo-provided global package (e.g. DOMO Notifications, DOMO DataSets, DOMO Users), the exported function names and their exact parameter signatures are not discoverable via the REST API — GET /api/codeengine/v2/packages/{id}/versions/{v} returns "functions": [] for all global packages.

How to find them: navigate to the package source in the Domo UI:

https://{instance}.domo.com/codeengine/{packageId}

This opens the Code Engine editor showing the full JavaScript source for the package. Read it to find:

• Exact exported function names (e.g. sendEmail, sendBuzzRequest)
• Positional parameter names and order (Code Engine maps by position, not key name)
• Which parameters are optional / nullable

Why this matters: guessing function names against the API returns 404 for every wrong name, giving no indication of what the correct name is. Without reading the source first, you will burn multiple round-trips and may need the user to paste the source manually.

Example — DOMO Notifications (03ba6971-98d0-4654-9bfd-aa897816df33)

Key functions found in source:

Gotcha: sendEmail takes recipientEmails as a plain string (e.g. "user@example.com"), not an array. Passing an array causes silent failure or incorrect routing.

Checklist

• Read package source at https://{instance}.domo.com/codeengine/{packageId} before writing any call
• Exact function name confirmed from source (do not guess)
• Parameter names and types confirmed from source JSDoc comments
• Calls use domo.post('/domo/codeengine/v2/packages/{alias}', params) pattern
• Manifest uses packagesMapping (not packageMapping)
• packagesMapping.version is explicitly pinned when deterministic package behavior is required
• packagesMapping.parameters and output include full contract fields (name, displayName, type, value, nullable, isList, children, entitySubType, alias)
• Agent states input parameter names, types, and nullable status to user
• Agent states expected output name/type/shape to user
• First implementation logs response and validates real response shape
• Output parsing handles body/data/raw response shape and nested response envelopes
• Errors handled and surfaced to UI or logs