Devin SDK structured output and launchSession

Launch a session

launchSession combines createSession and run on both cloud and local clients:

const { session, turn } = await devin.launchSession("Fix the flaky test");
const result = await turn; // Or stream events with: for await (const event of turn)

session takes the client’s creation options; turn takes the existing run options, including typed output. Launch waits for prompt acceptance, not work completion. On ACP v1, acceptance uses the matching user-message echo, falling back to the completion response if the agent doesn’t echo. Keep the client alive while using the turn; local work is not detached from the CLI. Cancel explicitly with session.cancel(). Startup failures after allocation throw SessionStartupError with sessionId and cause; inspect that session before retrying. Later execution failures reject turn.

Structured output

Pass a Zod (or any Standard Schema) schema as output and the turn resolves to a validated, typed value. A completed reply that doesn’t match the schema rejects the turn instead of returning bad data. A turn that stops without finishing — cancelled, refused, or out of tokens — resolves with that stopReason (since 0.0.1-beta.2; earlier betas rejected with “The turn produced no JSON to validate”): stopReason, text and events are readable, and reading outcome.output throws, so code that needs the value still fails loudly.

Zod is an optional dependency: npm install zod.

import { z } from "zod";

const outcome = await session.run("Outline a 3-section blog post about TypeScript unions", {
  output: z.object({ title: z.string(), sections: z.array(z.string()).length(3) }),
});
outcome.output.sections; // string[]

Typed output works on both clients without server-side session settings, and through launchSession:

import { z } from "zod";

const { turn } = await devin.launchSession("What is 6 times 7?", {
  turn: { output: z.object({ answer: z.number() }) },
});
const { output } = await turn; // { answer: number }

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Devin SDK structured output and launchSession

Launch a session

Structured output

​Launch a session

​Structured output

Launch a session

Structured output