AI Agent Patterns with Trigger.dev

Build production-ready AI agents using Trigger.dev's durable execution.

Trigger.dev 4.5 Agent Surfaces

Use the new 4.5 agent primitives when they match the shape of the work:

Need to...                              → Use
────────────────────────────────────────────────────────────
Build a durable AI SDK chat UI          → chat.agent
Resume one stream across run swaps      → Sessions
Version and dashboard-override prompts  → AI Prompts
Bundle procedural instructions/scripts  → Trigger Agent Skills
Run parallel local agent worktrees      → Dev branches

Durable chat agents

For AI chat surfaces backed by the Vercel AI SDK, prefer chat.agent over a hand-rolled API route. A chat agent is one long-lived Trigger.dev task per conversation, keyed by chat id, with durable session streams for refresh, redeploy, crash, idle, and reconnect behavior.

import { chat } from "@trigger.dev/sdk/ai";
import { streamText, stepCountIs } from "ai";
import { anthropic } from "@ai-sdk/anthropic";

export const myChat = chat.agent({
  id: "my-chat",
  run: async ({ messages, signal }) => {
    return streamText({
      // Spread first: this wires prompt, compaction, steering, skills,
      // background injection, and telemetry into the AI SDK call.
      ...chat.toStreamTextOptions(),
      model: anthropic("claude-sonnet-4-5"),
      messages,
      abortSignal: signal,
      stopWhen: stepCountIs(15),
    });
  },
});

Frontend integration uses useTriggerChatTransport from @trigger.dev/sdk/chat/react and passes that transport to useChat. Do not build a parallel streaming protocol unless useTriggerChatTransport cannot fit the product surface.

import { useChat } from "@ai-sdk/react";
import { useTriggerChatTransport } from "@trigger.dev/sdk/chat/react";
import type { myChat } from "@/trigger/chat";

export function Chat() {
  const transport = useTriggerChatTransport<typeof myChat>({
    task: "my-chat",
    accessToken: ({ chatId }) => mintChatAccessToken(chatId),
    startSession: ({ chatId, clientData }) =>
      startChatSession({ chatId, clientData }),
  });

  const { messages, sendMessage, stop, status } = useChat({ transport });
}

Sessions

Use the raw sessions API when the interaction is not quite chat-shaped but still needs durable bidirectional streaming across runs. A Session is the stable identity; runs can suspend, crash, upgrade, or be replaced while .in and .out continue under the same external id.

import { sessions, task } from "@trigger.dev/sdk";

export const inboxAgent = task({
  id: "inbox-agent",
  run: async (payload: { sessionId: string }) => {
    const session = sessions.open(payload.sessionId);

    while (true) {
      const next = await session.in.wait<{ text: string }>({ timeout: "1h" });
      if (!next.ok) return;
      await session.out.append({ type: "reply", text: `echo: ${next.output.text}` });
    }
  },
});

AI Prompts

Use prompts.define() when prompt text or model choice should be versioned on deploy and optionally overridden from the Trigger.dev dashboard. Resolve the prompt in a lifecycle hook, store it with chat.prompt.set(), then let chat.toStreamTextOptions() apply the system prompt, model/config, and telemetry.

import { prompts } from "@trigger.dev/sdk";
import { chat } from "@trigger.dev/sdk/ai";
import { createProviderRegistry, streamText, stepCountIs } from "ai";
import { anthropic } from "@ai-sdk/anthropic";
import { z } from "zod";

const registry = createProviderRegistry({ anthropic });

const systemPrompt = prompts.define({
  id: "my-chat-system",
  model: "anthropic:claude-sonnet-4-5",
  variables: z.object({ name: z.string() }),
  content: "You are a helpful assistant for {{name}}.",
});

export const myChat = chat.agent({
  id: "my-chat",
  onChatStart: async ({ clientData }) => {
    chat.prompt.set(await systemPrompt.resolve({ name: clientData.name }));
  },
  run: async ({ messages, signal }) => {
    return streamText({
      ...chat.toStreamTextOptions({ registry }),
      messages,
      abortSignal: signal,
      stopWhen: stepCountIs(15),
    });
  },
});

Trigger Agent Skills

Use Trigger Agent Skills for reusable folders of instructions plus optional scripts/references/assets that a chat.agent loads on demand. Skills are developer-authored code bundled into the deploy image; never accept skill paths from untrusted input.

import { skills } from "@trigger.dev/sdk";
import { chat } from "@trigger.dev/sdk/ai";
import { streamText } from "ai";
import { anthropic } from "@ai-sdk/anthropic";

const pdfSkill = skills.define({
  id: "pdf-processing",
  path: "./skills/pdf-processing",
});

export const docsChat = chat.agent({
  id: "docs-chat",
  onChatStart: async () => {
    chat.skills.set([await pdfSkill.local()]);
  },
  run: async ({ messages, signal }) => {
    return streamText({
      ...chat.toStreamTextOptions(),
      model: anthropic("claude-sonnet-4-5"),
      messages,
      abortSignal: signal,
    });
  },
});

chat.toStreamTextOptions() injects a short available-skills list plus scoped loadSkill, readFile, and bash tools. The model should call loadSkill before using a skill, then use the scoped tools against that skill's folder.

Dev branches

Trigger.dev 4.5 supports isolated local dev branches. Use trigger dev --branch <name> or set TRIGGER_DEV_BRANCH. In this repo, pnpm dev:trigger derives a branch name from git and passes it through so parallel worktrees or coding agents do not collide in the default dev environment.

HackerAI migration note

For HackerAI Agent mode, treat chat.agent as migration input, not a drop-in replacement. A live migration must preserve auth/suspension, sandbox setup, billing/refunds, budget monitoring, fallback models, todos, Convex persistence, and browser reconnect/resume behavior before swapping the current Agent stack.

Pattern Selection

Need to...                              → Use
─────────────────────────────────────────────────────
Build a durable Vercel AI SDK chat      → chat.agent
Stream a non-chat agent inbox           → Sessions
Bundle agent instructions/scripts       → Trigger Agent Skills
Process items in parallel               → Parallelization
Route to different models/handlers      → Routing
Chain steps with validation gates       → Prompt Chaining
Coordinate multiple specialized tasks   → Orchestrator-Workers
Self-improve until quality threshold    → Evaluator-Optimizer
Pause for human approval                → Human-in-the-Loop (waitpoints.md)
Stream progress to frontend             → Realtime Streams (streaming.md)
Let LLM call your tasks as tools        → ai.tool (ai-tool.md)

Core Patterns

1. Prompt Chaining (Sequential with Gates)

Chain LLM calls with validation between steps. Fail early if intermediate output is bad.

import { task } from "@trigger.dev/sdk";
import { generateText } from "ai";
import { openai } from "@ai-sdk/openai";

export const translateCopy = task({
  id: "translate-copy",
  run: async ({ text, targetLanguage, maxWords }) => {
    // Step 1: Generate
    const draft = await generateText({
      model: openai("gpt-4o"),
      prompt: `Write marketing copy about: ${text}`,
    });

    // Gate: Validate before continuing
    const wordCount = draft.text.split(/\s+/).length;
    if (wordCount > maxWords) {
      throw new Error(`Draft too long: ${wordCount} > ${maxWords}`);
    }

    // Step 2: Translate (only if gate passed)
    const translated = await generateText({
      model: openai("gpt-4o"),
      prompt: `Translate to ${targetLanguage}: ${draft.text}`,
    });

    return { draft: draft.text, translated: translated.text };
  },
});

2. Routing (Classify → Dispatch)

Use a cheap model to classify, then route to appropriate handler.

import { task } from "@trigger.dev/sdk";
import { generateText } from "ai";
import { openai } from "@ai-sdk/openai";
import { z } from "zod";

const routingSchema = z.object({
  model: z.enum(["gpt-4o", "o1-mini"]),
  reason: z.string(),
});

export const routeQuestion = task({
  id: "route-question",
  run: async ({ question }) => {
    // Cheap classification call
    const routing = await generateText({
      model: openai("gpt-4o-mini"),
      messages: [
        {
          role: "system",
          content: `Classify question complexity. Return JSON: {"model": "gpt-4o" | "o1-mini", "reason": "..."}
          - gpt-4o: simple factual questions
          - o1-mini: complex reasoning, math, code`,
        },
        { role: "user", content: question },
      ],
    });

    const { model } = routingSchema.parse(JSON.parse(routing.text));

    // Route to selected model
    const answer = await generateText({
      model: openai(model),
      prompt: question,
    });

    return { answer: answer.text, routedTo: model };
  },
});

3. Parallelization

Run independent LLM calls simultaneously with batch.triggerByTaskAndWait.

import { batch, task } from "@trigger.dev/sdk";

export const analyzeContent = task({
  id: "analyze-content",
  run: async ({ text }) => {
    // All three run in parallel
    const { runs: [sentiment, summary, moderation] } = await batch.triggerByTaskAndWait([
      { task: analyzeSentiment, payload: { text } },
      { task: summarizeText, payload: { text } },
      { task: moderateContent, payload: { text } },
    ]);

    // Check moderation first
    if (moderation.ok && moderation.output.flagged) {
      return { error: "Content flagged", reason: moderation.output.reason };
    }

    return {
      sentiment: sentiment.ok ? sentiment.output : null,
      summary: summary.ok ? summary.output : null,
    };
  },
});

See: references/orchestration.md for advanced patterns

4. Orchestrator-Workers (Fan-out/Fan-in)

Orchestrator extracts work items, fans out to workers, aggregates results.

import { batch, task } from "@trigger.dev/sdk";

export const factChecker = task({
  id: "fact-checker",
  run: async ({ article }) => {
    // Step 1: Extract claims (sequential - need output first)
    const { runs: [extractResult] } = await batch.triggerByTaskAndWait([
      { task: extractClaims, payload: { article } },
    ]);

    if (!extractResult.ok) throw new Error("Failed to extract claims");
    const claims = extractResult.output;

    // Step 2: Fan-out - verify all claims in parallel
    const { runs } = await batch.triggerByTaskAndWait(
      claims.map(claim => ({ task: verifyClaim, payload: claim }))
    );

    // Step 3: Fan-in - aggregate results
    const verified = runs
      .filter((r): r is typeof r & { ok: true } => r.ok)
      .map(r => r.output);

    return { claims, verifications: verified };
  },
});

5. Evaluator-Optimizer (Self-Refining Loop)

Generate → Evaluate → Retry with feedback until approved.

import { task } from "@trigger.dev/sdk";

export const refineTranslation = task({
  id: "refine-translation",
  run: async ({ text, targetLanguage, feedback, attempt = 0 }) => {
    // Bail condition
    if (attempt >= 5) {
      return { text, status: "MAX_ATTEMPTS", attempts: attempt };
    }

    // Generate (with feedback if retrying)
    const prompt = feedback
      ? `Improve this translation based on feedback:\n${feedback}\n\nOriginal: ${text}`
      : `Translate to ${targetLanguage}: ${text}`;

    const translation = await generateText({
      model: openai("gpt-4o"),
      prompt,
    });

    // Evaluate
    const evaluation = await generateText({
      model: openai("gpt-4o"),
      prompt: `Evaluate translation quality. Reply APPROVED or provide specific feedback:\n${translation.text}`,
    });

    if (evaluation.text.includes("APPROVED")) {
      return { text: translation.text, status: "APPROVED", attempts: attempt + 1 };
    }

    // Recursive self-call with feedback
    return refineTranslation.triggerAndWait({
      text,
      targetLanguage,
      feedback: evaluation.text,
      attempt: attempt + 1,
    }).unwrap();
  },
});

Trigger-Specific Features

Error Handling

const { runs } = await batch.triggerByTaskAndWait([...]);

// Check individual results
for (const run of runs) {
  if (run.ok) {
    console.log(run.output);  // Typed output
  } else {
    console.error(run.error);  // Error details
    console.log(run.taskIdentifier);  // Which task failed
  }
}

// Or filter by task type
const verifications = runs
  .filter((r): r is typeof r & { ok: true } =>
    r.ok && r.taskIdentifier === "verify-claim"
  )
  .map(r => r.output);

Quick Reference

// Trigger and wait for result
const result = await myTask.triggerAndWait(payload);
if (result.ok) console.log(result.output);

// Batch trigger same task
const results = await myTask.batchTriggerAndWait([
  { payload: item1 },
  { payload: item2 },
]);

// Batch trigger different tasks (typed)
const { runs } = await batch.triggerByTaskAndWait([
  { task: taskA, payload: { foo: 1 } },
  { task: taskB, payload: { bar: "x" } },
]);

// Self-recursion with unwrap
return myTask.triggerAndWait(newPayload).unwrap();