Eric Allam
d54bcaa29c
Follow-up to [#4644](https://github.com/triggerdotdev/trigger.dev/pull/4644), now rebased onto main so the diff is just these three commits. ## Summary Two ways a chat could lose a user message, both pre-existing and both raised while reviewing #4644. A message arriving while a turn was streaming was handed to that turn's push handler and parked in an in-memory array. The router counts a record handed to a handler as terminally decided, so it stopped holding the resume floor behind it, and the turn boundary published a cursor past a message that existed only in that process. A crash before the next turn lost it, silently. Measured: with the message at sequence 1, the boundary published `session-in-event-id: 1`, so a resume skipped it. Separately, a message the agent declined to inject was discarded with the turn. Never injected, never written to the wire buffer, never answered. That was also the documented default, since a `pendingMessages` config without `shouldInject` declines every batch. ## Design Notification and consumption are now separate concerns on the router. `observe` reports that a record arrived without taking it, so the record stays queued and keeps holding the floor. It is rejected on an `at-arrival` route: an observer there would either have to count as a listener, which would stop an unconsumed stop being discarded and bring back a wedged mailbox, or watch records it cannot affect. `take` removes exactly one queued record. The managed loop and the `chat.createSession()` iterator now only subscribe when there is a steering config to feed, and injection is the point of consumption. A declined batch never reaches the take, so its records stay queued and become later turns. Both in-memory wire buffers are gone, so a message waiting for its turn is durable rather than living in whichever worker received it. The floor doubles as the wake cursor: `awaitWake` registers with it and the server completes the waitpoint immediately if anything sits after that sequence. An over-advanced floor was therefore also a missed wake. It is now recorded on the wait span so a run that never woke can be diagnosed from its trace. ## Verification Both fixes have a red and green pair, each checked against the unmodified source rather than only observed to pass: - the resume cursor test fails on the parent branch and passes here - the declined-message test fails without the second commit and passes with it Also 8 new router tests for `observe` and `take`. Suites green at 385 for the SDK and 886 for core. ## Not addressed A `pendingMessages` config with no `chat.toStreamTextOptions()` spread still swallows messages, because nothing drains the queue at all. Same shape, different trigger, tracked separately.
Build and deploy fully‑managed AI agents and workflows
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About Trigger.dev
Trigger.dev is the open-source platform for building AI workflows in TypeScript. Long-running tasks with retries, queues, observability, and elastic scaling.
The platform designed for building AI agents
Build AI agents using all the frameworks, services and LLMs you're used to, deploy them to Trigger.dev and get durable, long-running tasks with retries, queues, observability, and elastic scaling out of the box.
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Long-running without timeouts: Execute your tasks with absolutely no timeouts, unlike AWS Lambda, Vercel, and other serverless platforms.
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Durability, retries & queues: Build rock solid agents and AI applications using our durable tasks, retries, queues and idempotency.
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True runtime freedom: Customize your deployed tasks with system packages – run browsers, Python scripts, FFmpeg and more.
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Human-in-the-loop: Programmatically pause your tasks until a human can approve, reject or give feedback.
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Realtime apps & streaming: Move your background jobs to the foreground by subscribing to runs or streaming AI responses to your app.
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Observability & monitoring: Each run has full tracing and logs. Configure error alerts to catch bugs fast.
Key features:
- JavaScript and TypeScript SDK - Build background tasks using familiar programming models
- Long-running tasks - Handle resource-heavy tasks without timeouts
- Durable cron schedules - Create and attach recurring schedules of up to a year
- Trigger.dev Realtime - Trigger, subscribe to, and get real-time updates for runs, with LLM streaming support
- Build extensions - Hook directly into the build system and customize the build process. Run Python scripts, FFmpeg, browsers, and more.
- React hooks - Interact with the Trigger.dev API on your frontend using our React hooks package
- Batch triggering - Use batchTrigger() to initiate multiple runs of a task with custom payloads and options
- Structured inputs / outputs - Define precise data schemas for your tasks with runtime payload validation
- Waits - Add waits to your tasks to pause execution for a specified duration
- Preview branches - Create isolated environments for testing and development. Integrates with Vercel and git workflows
- Waitpoints - Add human-in-the-loop judgment at critical decision points without disrupting workflow
- Concurrency & queues - Set concurrency rules to manage how multiple tasks execute
- Multiple environments - Support for DEV, PREVIEW, STAGING, and PROD environments
- No infrastructure to manage - Auto-scaling infrastructure that eliminates timeouts and server management
- Automatic retries - If your task encounters an uncaught error, we automatically attempt to run it again
- Checkpointing - Tasks are inherently durable, thanks to our checkpointing feature
- Versioning - Atomic versioning allows you to deploy new versions without affecting running tasks
- Machines - Configure the number of vCPUs and GBs of RAM you want the task to use
- Observability & monitoring - Monitor every aspect of your tasks' performance with comprehensive logging and visualization tools
- Logging & tracing - Comprehensive logging and tracing for all your tasks
- Tags - Attach up to ten tags to each run, allowing you to filter via the dashboard, realtime, and the SDK
- Run metadata - Attach metadata to runs which updates as the run progresses and is available to use in your frontend for live updates
- Bulk actions - Perform actions on multiple runs simultaneously, including replaying and cancelling
- Real-time alerts - Choose your preferred notification method for run failures and deployments
Write tasks in your codebase
Create tasks where they belong: in your codebase. Version control, localhost, test and review like you're already used to.
import { task } from "@trigger.dev/sdk";
//1. You need to export each task
export const helloWorld = task({
//2. Use a unique id for each task
id: "hello-world",
//3. The run function is the main function of the task
run: async (payload: { message: string }) => {
//4. You can write code that runs for a long time here, there are no timeouts
console.log(payload.message);
},
});
Deployment
Use our SDK to write tasks in your codebase. There's no infrastructure to manage, your tasks automatically scale and connect to our cloud. Or you can always self-host.
Environments
We support Development, Staging, Preview, and Production environments, allowing you to test your tasks before deploying them to production.
Full visibility of every job run
View every task in every run so you can tell exactly what happened. We provide a full trace view of every task run so you can see what happened at every step.
Getting started
The quickest way to get started is to create an account and project in our web app, and follow the instructions in the onboarding. Build and deploy your first task in minutes.
Useful links:
- Quick start - get up and running in minutes
- How it works - understand how Trigger.dev works under the hood
- Guides and examples - walk-through guides and code examples for popular frameworks and use cases
Self-hosting
If you prefer to self-host Trigger.dev, you can follow our self-hosting guides:
- Docker self-hosting guide - use Docker Compose to spin up a Trigger.dev instance
- Kubernetes self-hosting guide - use our official Helm chart to deploy Trigger.dev to your Kubernetes cluster
Support and community
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Development
To setup and develop locally or contribute to the open source project, follow our development guide.