openai-agents - Claude MCP Skill

# 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

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

**Tools**: Functions with Zod schemas
```typescript
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
```typescript
const triageAgent = Agent.create({ handoffs: [specialist1, specialist2] });
```

**Guardrails**: Input/output validation
```typescript
const agent = new Agent({ inputGuardrails: [detector], outputGuardrails: [filter] });
```

**Structured Outputs**: Type-safe responses
```typescript
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**:
```typescript
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

```typescript
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:

```typescript
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](https://github.com/openai/openai-agents-js/issues/806)

---

## Guardrails

**Input**: Validate before processing
```typescript
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

```typescript
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:

```typescript
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](https://github.com/openai/openai-agents-js/blob/main/examples/agent-patterns/human-in-the-loop-stream.ts)

---

## Realtime Voice Agents

**Create**:
```typescript
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**:
```typescript
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](https://github.com/openai/openai-agents-js/issues/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):
```typescript
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](https://github.com/openai/openai-agents-js/issues/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.

```typescript
// ❌ 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](https://github.com/openai/openai-agents-js/pull/887))

**Source**: [GitHub #188](https://github.com/openai/openai-agents-js/issues/188)

### 2. MCP Tracing Errors

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

**Workaround**:
```typescript
import { initializeTracing } from '@openai/agents/tracing';
await initializeTracing();
```

**Source**: [GitHub #580](https://github.com/openai/openai-agents-js/issues/580)

### 3. MaxTurnsExceededError

**Error**: Agent loops infinitely.

**Solution**: Increase maxTurns or improve instructions:

```typescript
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:

```typescript
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:

```typescript
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.

```typescript
// 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](https://github.com/openai/openai-agents-js/releases/tag/v0.4.0) | [PR #876](https://github.com/openai/openai-agents-js/pull/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.

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

**Source**: [Issue #844](https://github.com/openai/openai-agents-js/issues/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

```typescript
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):
1. `agent-basic.ts` - Simple agent with tools
2. `agent-handoffs.ts` - Multi-agent triage
3. `agent-structured-output.ts` - Zod schemas
4. `agent-streaming.ts` - Real-time events
5. `agent-guardrails-input.ts` - Input validation
6. `agent-guardrails-output.ts` - Output filtering
7. `agent-human-approval.ts` - HITL pattern
8. `agent-parallel.ts` - Concurrent execution

**Realtime Agents** (3):
9. `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

1. `agent-patterns.md` - Orchestration strategies
2. `common-errors.md` - 9 errors with workarounds
3. `realtime-transports.md` - WebRTC vs WebSocket
4. `cloudflare-integration.md` - Workers limitations
5. `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