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Approval Gate

<Approval> pauses a workflow at an explicit node, waits for a human decision, then continues.

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Workflow Definition

// approval-gate.tsx
import {
  Approval,
  Sequence,
  Task,
  approvalDecisionSchema,
  createSmithers,
} from "smithers-orchestrator";
import { ToolLoopAgent as Agent } from "ai";
import { anthropic } from "@ai-sdk/anthropic";
import { z } from "zod";

const { Workflow, smithers, outputs } = createSmithers({
  draft: z.object({
    title: z.string(),
    content: z.string(),
  }),
  publishApproval: approvalDecisionSchema,
  published: z.object({
    url: z.string(),
    publishedAt: z.string(),
  }),
});

const writer = new Agent({
  model: anthropic("claude-sonnet-4-5-20250929"),
  instructions:
    "You are a technical writer. Draft a blog post with a title and full content based on the given topic.",
});

const publisher = new Agent({
  model: anthropic("claude-sonnet-4-5-20250929"),
  instructions:
    "You are a publishing agent. Take the approved draft and return a URL and timestamp for the published post.",
});

export default smithers((ctx) => {
  const draft = ctx.outputMaybe(outputs.draft, { nodeId: "write-draft" });
  const decision = ctx.outputMaybe(outputs.publishApproval, {
    nodeId: "approve-publish",
  });

  return (
    <Workflow name="approval-gate">
      <Sequence>
        <Task id="write-draft" output={outputs.draft} agent={writer}>
          Write a blog post about deterministic AI workflows and why resumability
          matters for production systems.
        </Task>

        <Approval
          id="approve-publish"
          output={outputs.publishApproval}
          request={{
            title: "Publish blog post",
            summary: draft
              ? `Publish "${draft.title}" to the public site.`
              : "Publish the current draft.",
          }}
        />

        {decision?.approved ? (
          <Task id="publish" output={outputs.published} agent={publisher}>
            Publish this approved draft:{"\n\n"}
            Title: {draft?.title}
            {"\n\n"}
            {draft?.content}
          </Task>
        ) : null}
      </Sequence>
    </Workflow>
  );
});

​
Running

smithers up approval-gate.tsx --input '{}'

[approval-gate] Starting run mno345
[write-draft] Done -> { title: "Why Resumability Matters", content: "In production AI systems..." }
[approve-publish] Waiting for approval...
[approval-gate] Paused — run `smithers approve` or `smithers deny` to continue.

​
Approving or Denying

Approve and resume: 
smithers approve mno345 --node approve-publish
smithers up approval-gate.tsx --run-id mno345 --resume true

[approve-publish] Approved.
[publish] Running...
[publish] Done -> { url: "https://blog.example.com/resumability", publishedAt: "2026-02-10T12:00:00Z" }
[approval-gate] Completed
Deny and halt: 
smithers deny mno345 --node approve-publish

[approve-publish] Denied.
[approval-gate] Halted at node "approve-publish" (denied by user).

​
Listing Pending Approvals

smithers ps --status waiting-approval

{
  "runs": [
    {
      "id": "mno345",
      "workflow": "approval-gate",
      "status": "waiting-approval",
      "step": "approve-publish",
      "started": "2m ago"
    }
  ]
}

​
How It Works

  • <Approval> persists a decision object (approved, note, decidedBy, decidedAt) when the workflow resumes.
  • Re-running after approval replays completed tasks from the database and continues from the approval point.
  • Denial is permanent for that run. To retry, start a new run.