Cursor Sdk

Cursor SDK

The Cursor SDK runs Cursor agents programmatically. Two language variants share the same concepts:

• TypeScript (@cursor/sdk, npm) - docs at cursor.com/docs/sdk/typescript
• Python (cursor-sdk, pip) - docs at cursor.com/docs/sdk/python

Both are in public beta and follow the same Agent → Run model across local (runs on the caller's machine against cwd) and cloud (runs on a Cursor-hosted VM against a cloned repo) runtimes.

Pick the language

1. The user named it. Go with what they named.
2. The codebase signals it. pyproject.toml / .py files → Python. package.json / .ts files → TypeScript.
3. No signal either way. Ask: "TypeScript or Python?"

The Three Invocation Patterns

1. Agent.prompt(...) - one-shot

Fire-and-forget scripts, GitHub Actions steps, "send prompt, get result, exit" flows. No streaming, no follow-ups, no cleanup to remember.

TypeScript:

import { Agent } from "@cursor/sdk";
const result = await Agent.prompt("Refactor src/utils.ts for readability", {
  apiKey: process.env.CURSOR_API_KEY!,
  model: { id: "composer-2.5" },
  local: { cwd: process.cwd() },
});
console.log(result.status, result.result);

Python:

from cursor_sdk import Agent, AgentOptions, LocalAgentOptions
result = Agent.prompt(
    "Refactor src/utils.py for readability",
    AgentOptions(api_key=os.environ["CURSOR_API_KEY"], model="composer-2.5",
                 local=LocalAgentOptions(cwd=os.getcwd())),
)
print(result.status, result.result)

2. Agent.create(...) + agent.send(...) - durable with follow-ups

Streaming, multi-turn conversation, lifecycle operations (cancel, status listener).

TypeScript:

import { Agent } from "@cursor/sdk";
await using agent = await Agent.create({
  apiKey: process.env.CURSOR_API_KEY!, model: { id: "composer-2.5" },
  local: { cwd: process.cwd() },
});
const run = await agent.send("Find the bug in src/auth.ts");
for await (const event of run.stream()) {
  if (event.type === "assistant")
    for (const block of event.message.content)
      if (block.type === "text") process.stdout.write(block.text);
}
await run.wait();
const run2 = await agent.send("Now write a regression test for it");
await run2.wait();

Python:

from cursor_sdk import Agent, LocalAgentOptions
with Agent.create(model="composer-2.5", api_key=os.environ["CURSOR_API_KEY"],
                  local=LocalAgentOptions(cwd=os.getcwd())) as agent:
    run = agent.send("Find the bug in src/auth.py")
    for message in run.messages():
        if message.type == "assistant":
            for block in message.message.content:
                if block.type == "text": print(block.text, end="")
    run.wait()
    run2 = agent.send("Now write a regression test for it")
    run2.wait()

3. Agent.resume(...) - pick up an existing agent later

Cross-process boundaries: cron continuations, webhooks, interactive CLIs. Runtime is auto-detected from the ID prefix — bc- is cloud, anything else is local.

TypeScript:

await using agent = await Agent.resume(previousAgentId, { apiKey });
const run = await agent.send("Also update the changelog");
await run.wait();

Python:

with Agent.resume(previous_agent_id, AgentOptions(api_key=os.environ["CURSOR_API_KEY"])) as agent:
    run = agent.send("Also update the changelog")
    run.wait()

Inline MCP servers are not persisted across resume — pass them again.

Top Five Traps

1. Wrong runtime by accident: Always set local or cloud explicitly — the SDK defaults to local silently.
2. Two kinds of failure: Thrown CursorAgentError = run never executed (auth, config). result.status == "error" = run executed and failed. Different fixes.
3. Forgetting to dispose: Use await using (TS) or with ... as agent: (Python). Skipping disposal leaks child processes and memory.
4. Streaming is optional but wait() is required: wait() returns the terminal result. Always call it.
5. Not every operation is supported on every runtime: Guard with run.supports("cancel") before calling.

Local vs Cloud

• Local — runs on the caller's machine against cwd. Good for dev loops and CI with a repo checkout.
• Cloud — runs on a Cursor-hosted VM against a freshly cloned repo. Good for long jobs and fire-and-forget automation.

Auth

export CURSOR_API_KEY="cursor_..."

Both SDKs read CURSOR_API_KEY when no key is passed explicitly.

Model Selection

composer-2.5 is the current default. model="auto" lets the server pick. Cursor.models.list() returns valid IDs.

MCP Servers

Both SDKs support HTTP (with headers or OAuth auth) or stdio (command / args / env). Pass servers inline on Agent.create or agent.send.

• Inline servers fully replace creation-time servers on a per-send override — not merged.
• Resume requires re-passing servers — they are not persisted.

Production Best Practices

1. Always dispose. await using (TS) or with ... as agent: (Python).
2. Distinguish startup vs run failures. Exit 1 for CursorAgentError, exit 2 for result.status == "error".
3. Log run.id and agent.agentId immediately after send().
4. Respect error.isRetryable. Blind retries can cause duplicate cloud runs.
5. Always pass apiKey explicitly in shared-infrastructure code.
6. Prefer Agent.prompt(...) for true one-shots — it disposes for you.