Cursor SDK opens the harness up

Cursor shipped a TypeScript SDK on April 29 — the same runtime, harness, and models that power the desktop app, CLI, and web client, now available programmatically via npm install @cursor/sdk. Public beta, token-based pricing; SDK examples now default to Composer 2.5 (Cursor's in-house coding model — roughly 10× cheaper per input token than both Opus 4.7 and GPT-5.5).

Agents created through the SDK get the full stack: codebase indexing with semantic search and instant grep, MCP servers, skills from .cursor/skills/, and hooks from .cursor/hooks.json. Execution can target sandboxed cloud VMs (Cursor-managed), self-hosted workers (your network), or your local machine. Subagents, streaming, and the same harness primitives that ship in the IDE are exposed as composable APIs.

The cookbook is the part to look at. Four reference projects: a minimal quickstart, a web-based prototyping tool that scaffolds new projects in a sandbox, a lightweight coding-agent CLI, and the agent-kanban board — a Linear-style UI where each card represents a Cloud Agent. Drag a card to "in progress" and the agent picks the work up, runs to completion in a sandbox, opens a PR, and posts the result back to the card as an attachment. The board lists running agents, groups them into columns, previews artifacts inline, and creates new agents from a repo + prompt.

Practical read: the SDK turns Cursor from "an editor with agents" into "agent runtime you can build on." If you've been wiring up your own agent loops over the Anthropic or OpenAI APIs, the SDK is shorter — you inherit indexing, hooks, subagents, and sandboxing instead of reinventing them. The kanban example is the cleanest demonstration of where this lands: tickets become agent invocations, drag-and-drop becomes scheduling, and PRs become the artifact.