Function code

For questions about sandbox APIs, fetch behavior, limits, traces, or function errors that this skill does not answer, follow the docs MCP workflow before answering or implementing. For every new Voiceflow troubleshooting issue, consult it even when this skill suggests a fix. Include package/skill/stage context in why as described there. Reuse guidance for the same issue; consult it whenever unsure.

Read the operation contract. Prefer an existing integration for a supported action, an API tool for one HTTP request, and a function for transformation, branching, or composed logic.

Functions run in Voiceflow's sandbox, not Node or a browser. Use export default async function main(args) and declared inputs from args.inputVars. Do not assume imports, require, process, Buffer, DOM, or browser URL utilities exist.

Voiceflow's modified fetch exposes parsed response properties: const data = (await fetch(url)).json, not response.json(). Inspect the documented status and error shape; never log credentials or full customer payloads. Check current sandbox limits before large responses or custom traces.

Return outputVars with names matching declared outputs and supported scalar types. Serialize structured data deliberately. Declare every path returned as next: { path: 'success' }; a missing/mismatched path can stop execution. Return a defined result on every branch.

Creating a function does not attach it to an agent. Declare inputs, outputs, and paths, then create the attachment with a WHAT + WHEN description. Read wiring for defaults and captured results.

Secrets arrive through declared inputs bound to secret references on the attachment; never read args.secrets. Tests may call real services, so use fixtures first and only execute an integration with task authorization.

Source: Function tool.

---
name: voiceflow-functions
description: Create or debug Voiceflow function code, sandbox behavior, fetch parsing, outputs, and exit paths. Use when logic cannot be handled by an existing integration or one API request.
license: MIT
---