---
title: "Transform MCP functions"
description: "MCP functions for managing transform."
section: "MCP"
group: "Functions"
order: 703
---

## Functions

### `transform`

Reshape JSON data via a jq expression. Covers filter (select), project (map), sort (sort_by), group (group_by), aggregate (reduce/length), reshape, string ops (split/join/gsub), regex (test/gsub with Oniguruma), update-assign (|=), and user-defined functions (def). The underlying DSL is jq 1.8. Use between function calls to reshape output for the next call's input. Example: `{ input: { items: [...] }, expression: '.items | map(.id)' }` → `[1, 2, 3]`. See also the `transform-function` skill for common patterns.

```ts
transform(input: { input: unknown; expression: string }): Promise<unknown>
```