Add experimental tool.group() for Sandboxes

[jpwilliams]

Summary

Sandbox code can now call tool.group() tools, whose body is a group of steps. Run steps in parallel, invoke other functions and use their result, send events, or wait for one, all from a single tool call.

import { step } from "inngest";
import { tool } from "inngest/experimental";

const refund = tool.group({
  input: z.object({ orderId: z.string() }),
  run: async ({ orderId }) => {
    const result = await step.invoke("refund", {
      function: refundFn,
      data: { orderId },
    });

    await step.sendEvent("notify", { name: "order/refunded", data: result });

    return result;
  },
});

Checklist

• Added a docs PR that references this PR N/A Later bump
• Added unit/integration tests
• Added changesets if applicable

[changeset-bot]

🦋 Changeset detected

Latest commit: 9f48b6b

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
inngest	Patch

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[greptile-apps]

Confidence Score: 4/5

[Medium impact] Adds experimental tool.group feature for sandbox execution.

Fix the shared-directory collision for nested sandbox commands before merging.

Findings

1.  Nested commands share results ▶
2.  Library step origins disappear ▶

Fix with agent prompt

### Issue 1
packages/inngest/src/components/sandbox/toolRunner.ts:290
If two calls to the same `tool.group()` run `sandbox.commands.run("inner", ..., { tools })` on a shared sandbox, this prefix separates their durable step IDs but not their working directories. The nested `followCommand()` builds its directory from the raw `"inner"` ID and `runId`. The wrapper treats the second command as a retry and skips starting it, so both callers can read the first command's requests and result.

Include the active prefix when deriving the command directory and tool idempotency keys.

### Issue 2
packages/inngest/src/components/InngestStepTools.ts:401-402
The `prefix` check drops origins from every span inside a group tool, including spans explicitly created by a library inside the tool body. A nested `group["~span"]({ id: "work", origin: "@inngest/ci@0.1.0" }, ...)` no longer passes that origin to its steps. This breaks the documented inheritance rule and makes library-created steps look like user-written work.

Suppress the outer tool span's origin without suppressing origins set by inner spans.

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

Summary

Adds experimental tool.group() so sandbox tools can run several durable steps and return their combined result.

• Sandbox tool calls can run a group of real steps.

Diagram

%%{init: {'theme': 'neutral'}}%%
flowchart TD
  A[Sandbox calls a tool] --> B[Check tool and arguments]
  B --> C{Group tool?}
  C -->|No| D[Run one durable tool step]
  C -->|Yes| E[Add tool span and call prefix]
  E --> F[Run body with inner durable steps]
  D --> G[Check output and build reply]
  F --> G
  G --> H[Durable wait step appends reply]
  H --> I[Sandbox continues]

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_{Reviews (1) · Last reviewed commit: "feat(sandbox): tool.group, a tool whose ..." · Reviewed by Greptile}