JSON to JSONP Skill

Overview

Send a POST request containing a raw JSON object or stringified JSON payload along with an optional callback name. If omitted, the callback defaults to callback. The endpoint validates the JavaScript identifier, including dotted names, and encapsulates the payload into an executable JSONP string, returning both the callback name and the wrapped result.

Live Test JSON to JSONP Skill Skill →

The tool

Once your client is connected to the VerveKit server, this appears in its tool list as JSONtoJSONPSkill. It is read-only and open-world — it fetches and never mutates anything on your side — so most clients call it without asking you to confirm.

Tool call

{
  "name": "JSONtoJSONPSkill",
  "arguments": {
    "json": "{\"name\":\"John Doe\",\"age\":30,\"city\":\"New York\"}"
  }
}

You do not name the tool yourself; the model picks it. Asking about {"name":"John Doe","age":30,"city":"New York"} in the terms this skill covers is enough for it to reach for JSONtoJSONPSkill on its own — naming it explicitly also works, and is the way to force the call.

Connecting

One server URL covers every skill in the catalog, including this one. Authorization is OAuth: the client opens a browser once, and there is no key to paste into a config file.

{
  "mcpServers": {
    "vervekit": {
      "url": "https://api.vervekit.com/v1/mcp"
    }
  }
}

Per-client setup — Claude, Cursor, VS Code, ChatGPT — is on the MCP setup page.

Arguments

These are the properties on the tool's inputSchema, so a well-behaved client validates them before the call is made. Premium arguments are accepted on every plan but only take effect on plans that include them.

Argument	Type	Description
`json`Required	object	The JSON data you want converted into JSONP format. Send it as an object or as a JSON-encoded string.
`callback`Optional	string	The callback function name to wrap the JSON data. Must be a JavaScript identifier, optionally dotted (e.g. myCallback or window.myCallback). default callback

What the model gets back

The result carries a structuredContent object matching the tool's declared outputSchema, so a client reads fields without parsing prose. status is "ok" and error is null on success; a null field means the value was not available for that input, not that the call failed.

Result

{
  "status": "ok",
  "error": null,
  "data": {
    "callback": "callbackFunction",
    "jsonp": "callbackFunction({\"menu\":{\"id\":\"file\",\"value\":\"File\",\"popup\":false}});"
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Field	Type	Example	Description
`callback`	string	`callbackFunction`	Echoes back the callback function name provided
`jsonp`	string	`callbackFunction({"menu":{"id":"file","value":"File","popup":false}});`	JSON data wrapped in JSONP format with callback function

Failure modes

Errors come back as tool errors carrying a sentence the model can act on, not a bare status code. Error handling covers the full list.

Status	What it means
`400` / `422`	The arguments did not validate. The message names the offending one.
`401`	The OAuth session is invalid or expired — reconnect the server.
`403`	Blocked by a key restriction or an IP allow-list. Never a bad identity.
`404`	This skill is not part of VerveKit. Check the catalog.
`429`	Out of credits, or a brief rate limit. The message tells them apart.

A call costs 2 credits each time the tool actually runs; a model that reasons about the tool without calling it costs nothing.

Use cases

Cross-Domain Widget Feeds: When third-party embed widgets need cross-domain data without CORS configuration, developers serve JSON payloads wrapped in dynamic client callback functions.
Legacy Portal Maintenance: Engineers supporting legacy enterprise portals convert modern JSON API outputs into JSONP responses so older web clients can parse responses through script tags.
Static Documentation Embeds: Technical writers embed live remote status objects into static HTML documentation sites by wrapping JSON records in custom callback handlers.
Client Mashup Prototyping: To test multi-domain data feeds before updating server headers, frontend developers convert mock JSON datasets into callback-wrapped strings on demand.

Other ways to use JSON to JSONP Skill

Set up JSON to JSONP Skill on VerveKit, or reach the same source a different way. Your VerveKit account and credits work on all of them — one key, one balance.

Call it as a REST APIOne HTTPS endpoint and an x-api-key header, with SDKs for Node, Python and .NET.APIVerve →Reference →