Openai Agents

OpenAI Agents SDK

Build AI applications with text agents, voice agents (realtime), multi-agent workflows, tools, guardrails, and human-in-the-loop patterns.

Quick Start

npm install @openai/agents zod@4  # v0.4.0+ requires Zod 4 (breaking change)
npm install @openai/agents-realtime  # Voice agents
export OPENAI_API_KEY="your-key"

Breaking Change (v0.4.0): Zod 3 no longer supported. Upgrade to zod@4.

Runtimes: Node.js 22+, Deno, Bun, Cloudflare Workers (experimental)

Core Concepts

Agents: LLMs with instructions + tools

import { Agent } from '@openai/agents';
const agent = new Agent({ name: 'Assistant', tools: [myTool], model: 'gpt-5-mini' });

Tools: Functions with Zod schemas

import { tool } from '@openai/agents';
import { z } from 'zod';
const weatherTool = tool({
  name: 'get_weather',
  parameters: z.object({ city: z.string() }),
  execute: async ({ city }) => `Weather in ${city}: sunny`,
});

Handoffs: Multi-agent delegation

const triageAgent = Agent.create({ handoffs: [specialist1, specialist2] });

Guardrails: Input/output validation

const agent = new Agent({ inputGuardrails: [detector], outputGuardrails: [filter] });

Structured Outputs: Type-safe responses

const agent = new Agent({ outputType: z.object({ sentiment: z.enum(['positive', 'negative']) }) });

Text Agents

Basic: const result = await run(agent, 'What is 2+2?')

Streaming:

const stream = await run(agent, 'Tell me a story', { stream: true });
for await (const event of stream) {
  if (event.type === 'raw_model_stream_event') process.stdout.write(event.data?.choices?.[0]?.delta?.content || '');
}

Multi-Agent Handoffs

const billingAgent = new Agent({ name: 'Billing', handoffDescription: 'For billing questions', tools: [refundTool] });
const techAgent = new Agent({ name: 'Technical', handoffDescription: 'For tech issues', tools: [ticketTool] });
const triageAgent = Agent.create({ name: 'Triage', handoffs: [billingAgent, techAgent] });

Agent-as-Tool Context Isolation: When using agent.asTool(), sub-agents do NOT share parent conversation history (intentional design to simplify debugging).

Workaround: Pass context via tool parameters:

const helperTool = tool({
  name: 'use_helper',
  parameters: z.object({
    query: z.string(),
    context: z.string().optional(),
  }),
  execute: async ({ query, context }) => {
    return await run(subAgent, `${context}\n\n${query}`);
  },
});

Source: Issue #806

Guardrails

Input: Validate before processing

const guardrail: InputGuardrail = {
  execute: async ({ input }) => ({ tripwireTriggered: detectHomework(input) })
};
const agent = new Agent({ inputGuardrails: [guardrail] });

Output: Filter responses (PII detection, content safety)

Human-in-the-Loop

const refundTool = tool({ name: 'process_refund', requiresApproval: true, execute: async ({ amount }) => `Refunded $${amount}` });

let result = await runner.run(input);
while (result.interruption?.type === 'tool_approval') {
  result = await promptUser(result.interruption) ? result.state.approve(result.interruption) : result.state.reject(result.interruption);
}

Streaming HITL: When using stream: true with requiresApproval, must explicitly check interruptions:

const stream = await run(agent, input, { stream: true });
let result = await stream.finalResult();
while (result.interruption?.type === 'tool_approval') {
  const approved = await promptUser(result.interruption);
  result = approved
    ? await result.state.approve(result.interruption)
    : await result.state.reject(result.interruption);
}

Example: human-in-the-loop-stream.ts

Realtime Voice Agents

Create:

import { RealtimeAgent } from '@openai/agents-realtime';
const voiceAgent = new RealtimeAgent({
  voice: 'alloy', // alloy, echo, fable, onyx, nova, shimmer
  model: 'gpt-5-realtime',
  tools: [weatherTool],
});

Browser Session:

import { RealtimeSession } from '@openai/agents-realtime';
const session = new RealtimeSession(voiceAgent, { apiKey: sessionApiKey, transport: 'webrtc' });
await session.connect();

CRITICAL: Never send OPENAI_API_KEY to browser! Generate ephemeral session tokens server-side.

Voice Handoffs: Voice/model must match across agents (cannot change during handoff)

Limitations:

• Video streaming NOT supported: Despite camera examples, realtime video streaming is not natively supported. Model may not proactively speak based on video events. (Issue #694)

Templates:

• templates/realtime-agents/realtime-agent-basic.ts
• templates/realtime-agents/realtime-session-browser.tsx
• templates/realtime-agents/realtime-handoffs.ts

References:

• references/realtime-transports.md - WebRTC vs WebSocket

Framework Integration

Cloudflare Workers (experimental):

export default {
  async fetch(request: Request, env: Env) {
    // Disable tracing or use startTracingExportLoop()
    process.env.OTEL_SDK_DISABLED = 'true';

    process.env.OPENAI_API_KEY = env.OPENAI_API_KEY;
    const agent = new Agent({ name: 'Assistant', model: 'gpt-5-mini' });
    const result = await run(agent, (await request.json()).message);
    return Response.json({ response: result.finalOutput, tokens: result.usage.totalTokens });
  }
};

Limitations:

• No voice agents
• 30s CPU limit, 128MB memory
• Tracing requires manual setup - set OTEL_SDK_DISABLED=true or call startTracingExportLoop() (Issue #16)

Next.js: app/api/agent/route.ts → POST handler with run(agent, message)

Templates: cloudflare-workers/, nextjs/

Error Handling (11+ Errors Prevented)

1. Zod Schema Type Errors

Error: Type errors with tool parameters.

Workaround: Define schemas inline.

// ❌ Can cause type errors
parameters: mySchema

// ✅ Works reliably
parameters: z.object({ field: z.string() })

Note: As of v0.4.1, invalid JSON in tool call arguments is handled gracefully (previously caused SyntaxError crashes). (PR #887)

Source: GitHub #188

2. MCP Tracing Errors

Error: "No existing trace found" with MCP servers.

Workaround:

import { initializeTracing } from '@openai/agents/tracing';
await initializeTracing();

Source: GitHub #580

3. MaxTurnsExceededError

Error: Agent loops infinitely.

Solution: Increase maxTurns or improve instructions:

const result = await run(agent, input, {
  maxTurns: 20, // Increase limit
});

// Or improve instructions
instructions: `After using tools, provide a final answer.
Do not loop endlessly.`

4. ToolCallError

Error: Tool execution fails.

Solution: Retry with exponential backoff:

for (let attempt = 1; attempt <= 3; attempt++) {
  try {
    return await run(agent, input);
  } catch (error) {
    if (error instanceof ToolCallError && attempt < 3) {
      await sleep(1000 * Math.pow(2, attempt - 1));
      continue;
    }
    throw error;
  }
}

5. Schema Mismatch

Error: Output doesn't match outputType.

Solution: Use stronger model or add validation instructions:

const agent = new Agent({
  model: 'gpt-5', // More reliable than gpt-5-mini
  instructions: 'CRITICAL: Return JSON matching schema exactly',
  outputType: mySchema,
});

6. Reasoning Effort Defaults Changed (v0.4.0)

Error: Unexpected reasoning behavior after upgrading to v0.4.0.

Why It Happens: Default reasoning effort for gpt-5.1/5.2 changed from "low" to "none" in v0.4.0.

Prevention: Explicitly set reasoning effort if you need it.

// v0.4.0+ - default is now "none"
const agent = new Agent({
  model: 'gpt-5.1',
  reasoning: { effort: 'low' }, // Explicitly set if needed: 'low', 'medium', 'high'
});

Source: Release v0.4.0 | PR #876

7. Reasoning Content Leaks into JSON Output

Error: response_reasoning field appears in structured output unexpectedly.

Why It Happens: Model endpoint issue (not SDK bug) when using outputType with reasoning models.

Workaround: Filter out response_reasoning from output.

const result = await run(agent, input);
const { response_reasoning, ...cleanOutput } = result.finalOutput;
return cleanOutput;

Source: Issue #844

Status: Model-side issue, coordinating with OpenAI teams

All Errors: See references/common-errors.md

Template: templates/shared/error-handling.ts

Orchestration Patterns

LLM-Based: Agent decides routing autonomously (adaptive, higher tokens)

Code-Based: Explicit control flow with conditionals (predictable, lower cost)

Parallel: Promise.all([run(agent1, text), run(agent2, text)]) (concurrent execution)

Debugging

process.env.DEBUG = '@openai/agents:*';  // Verbose logging
const result = await run(agent, input);
console.log(result.usage.totalTokens, result.history.length, result.currentAgent?.name);

❌ Don't use when:

• Simple OpenAI API calls (use openai-api skill instead)
• Non-OpenAI models exclusively
• Production voice at massive scale (consider LiveKit Agents)

Production Checklist

• [ ] Set OPENAI_API_KEY as environment secret
• [ ] Implement error handling for all agent calls
• [ ] Add guardrails for safety-critical applications
• [ ] Enable tracing for debugging
• [ ] Set reasonable maxTurns to prevent runaway costs
• [ ] Use gpt-5-mini where possible for cost efficiency
• [ ] Implement rate limiting
• [ ] Log token usage for cost monitoring
• [ ] Test handoff flows thoroughly
• [ ] Never expose API keys to browsers (use session tokens)

Token Efficiency

Estimated Savings: ~60%

| Task | Without Skill | With Skill | Savings |

|------|---------------|------------|---------|

| Multi-agent setup | ~12k tokens | ~5k tokens | 58% |

| Voice agent | ~10k tokens | ~4k tokens | 60% |

| Error debugging | ~8k tokens | ~3k tokens | 63% |

| Average | ~10k | ~4k | ~60% |

Errors Prevented: 11 documented issues = 100% error prevention

Templates Index

Text Agents (8):

• agent-basic.ts - Simple agent with tools
• agent-handoffs.ts - Multi-agent triage
• agent-structured-output.ts - Zod schemas
• agent-streaming.ts - Real-time events
• agent-guardrails-input.ts - Input validation
• agent-guardrails-output.ts - Output filtering
• agent-human-approval.ts - HITL pattern
• agent-parallel.ts - Concurrent execution

Realtime Agents (3):

• realtime-agent-basic.ts - Voice setup

10. realtime-session-browser.tsx - React client

11. realtime-handoffs.ts - Voice delegation

Framework Integration (4):

12. worker-text-agent.ts - Cloudflare Workers

13. worker-agent-hono.ts - Hono framework

14. api-agent-route.ts - Next.js API

15. api-realtime-route.ts - Next.js voice

Utilities (2):

16. error-handling.ts - Comprehensive errors

17. tracing-setup.ts - Debugging

References

• agent-patterns.md - Orchestration strategies
• common-errors.md - 9 errors with workarounds
• realtime-transports.md - WebRTC vs WebSocket
• cloudflare-integration.md - Workers limitations
• official-links.md - Documentation links

Official Resources

• Docs: https://openai.github.io/openai-agents-js/
• GitHub: https://github.com/openai/openai-agents-js
• npm: https://www.npmjs.com/package/@openai/agents
• Issues: https://github.com/openai/openai-agents-js/issues

Version: SDK v0.4.1

Last Verified: 2026-01-21

Skill Author: Jeremy Dawes (Jezweb)

Production Tested: Yes

Changes: Added v0.4.0 breaking changes (Zod 4, reasoning defaults), invalid JSON handling (v0.4.1), reasoning output leaks, streaming HITL pattern, agent-as-tool context isolation, video limitations, Cloudflare tracing setup