Skill.md
- SKILL.md
--- name: dsl-vm-reverse description: Reverse JavaScript-based custom DSL/VM interpreters and risk-control engines: identify IIFE/switch-based opcode dispatch, extract opcode tables, and capture runtime semantics. ---
Skill.md
Guide for building reliable, fault-tolerant TypeScript applications with DBOS durable workflows. Use when adding DBOS to existing TypeScript code, creating workflows and steps, or using queues for concurrency control.
SKILL.md
---
name: dbos-typescript
description: "Guide for building reliable, fault-tolerant TypeScript applications with DBOS durable workflows. Use when adding DBOS to existing TypeScript code, creating workflows and steps, or using queues for concurrency control."
risk: safe
source: "https://docs.dbos.dev/"
date_added: "2026-02-27"
---
# DBOS TypeScript Best Practices
Guide for building reliable, fault-tolerant TypeScript applications with DBOS durable workflows.
## When to Use
Reference these guidelines when:
- Adding DBOS to existing TypeScript code
- Creating workflows and steps
- Using queues for concurrency control
- Implementing workflow communication (events, messages, streams)
- Configuring and launching DBOS applications
- Using DBOSClient from external applications
- Testing DBOS applications
## Rule Categories by Priority
| Priority | Category | Impact | Prefix |
|----------|----------|--------|--------|
| 1 | Lifecycle | CRITICAL | `lifecycle-` |
| 2 | Workflow | CRITICAL | `workflow-` |
| 3 | Step | HIGH | `step-` |
| 4 | Queue | HIGH | `queue-` |
| 5 | Communication | MEDIUM | `comm-` |
| 6 | Pattern | MEDIUM | `pattern-` |
| 7 | Testing | LOW-MEDIUM | `test-` |
| 8 | Client | MEDIUM | `client-` |
| 9 | Advanced | LOW | `advanced-` |
## Critical Rules
### Installation
Always install the latest version of DBOS:
```bash
npm install @dbos-inc/dbos-sdk@latest
```
### DBOS Configuration and Launch
A DBOS application MUST configure and launch DBOS before running any workflows:
```typescript
import { DBOS } from "@dbos-inc/dbos-sdk";
async function main() {
DBOS.setConfig({
name: "my-app",
systemDatabaseUrl: process.env.DBOS_SYSTEM_DATABASE_URL,
});
await DBOS.launch();
await myWorkflow();
}
main().catch(console.log);
```
### Workflow and Step Structure
Workflows are comprised of steps. Any function performing complex operations or accessing external services must be run as a step using `DBOS.runStep`:
```typescript
import { DBOS } from "@dbos-inc/dbos-sdk";
async function fetchData() {
return await fetch("https://api.example.com").then(r => r.json());
}
async function myWorkflowFn() {
const result = await DBOS.runStep(fetchData, { name: "fetchData" });
return result;
}
const myWorkflow = DBOS.registerWorkflow(myWorkflowFn);
```
### Key Constraints
- Do NOT call, start, or enqueue workflows from within steps
- Do NOT use threads or uncontrolled concurrency to start workflows - use `DBOS.startWorkflow` or queues
- Workflows MUST be deterministic - non-deterministic operations go in steps
- Do NOT modify global variables from workflows or steps
## How to Use
Read individual rule files for detailed explanations and examples:
```
references/lifecycle-config.md
references/workflow-determinism.md
references/queue-concurrency.md
```
## References
- https://docs.dbos.dev/
- https://github.com/dbos-inc/dbos-transact-ts
## Limitations
- Use this skill only when the task clearly matches the scope described above.
- Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
- Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.
Use when adding DBOS to existing TypeScript code, creating workflows and steps, or using queues for concurrency control.