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api/beta-headers.md

Changed on 2026-05-28 14:32:15 EST

+4 lines added
-4 lines removed
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# Beta headers¶

Documentation for using beta headers with the Claude API¶

---¶

Beta headers allow you to access experimental features and new model capabilities before they become part of the standard API.¶

These features are subject to change and may be modified or removed in future releases.¶

<Info>¶
Beta headers are often used in conjunction with the [beta namespace in the client SDKs](/docs/en/api/client-sdks#beta-namespace-in-client-sdks)¶
</Info>¶

## How to use beta headers¶

To access beta features, include the `anthropic-beta` header in your API requests:¶

```http¶
POST /v1/messages¶
Content-Type: application/json¶
X-API-Key: YOUR_API_KEY¶
anthropic-beta: BETA_FEATURE_NAME¶
```¶

When using the SDK, you can specify beta headers in the request options:¶

<CodeGroup>¶

```bash cURL¶
curl https://api.anthropic.com/v1/messages \¶
-H "x-api-key: $ANTHROPIC_API_KEY" \¶
-H "anthropic-version: 2023-06-01" \¶
-H "anthropic-beta: files-api-2025-04-14" \¶
-H "content-type: application/json" \¶
-d '{¶
"model": "claude-opus-4-78",¶
"max_tokens": 1024,¶
"messages": [¶
{"role": "user", "content": "Hello, Claude"}¶
]¶
}'¶
```¶

```bash CLI¶
ant beta:messages create \¶
--beta files-api-2025-04-14 \¶
--model claude-opus-4-78 \¶
--max-tokens 1024 \¶
--message '{role: user, content: "Hello, Claude"}'¶
```¶

```python Python hidelines={1..2}¶
from anthropic import Anthropic¶

client = Anthropic()¶

response = client.beta.messages.create(¶
model="claude-opus-4-78",¶
max_tokens=1024,¶
messages=[{"role": "user", "content": "Hello, Claude"}],¶
betas=["files-api-2025-04-14"],¶
)¶
```¶

```typescript TypeScript hidelines={1..2}¶
import Anthropic from "@anthropic-ai/sdk";¶

const anthropic = new Anthropic();¶

const msg = await anthropic.beta.messages.create({¶
model: "claude-opus-4-78",¶
max_tokens: 1024,¶
messages: [{ role: "user", content: "Hello, Claude" }],¶
betas: ["files-api-2025-04-14"]¶
});¶
```¶

</CodeGroup>¶

<Warning>¶
Beta features are experimental and may:¶
- Have breaking changes with notice¶
- Be deprecated or removed¶
- Have different rate limits or pricing¶
- Not be available in all regions¶
</Warning>¶

### Multiple beta features¶

To use multiple beta features in a single request, include all feature names in the header separated by commas:¶

```http¶
anthropic-beta: feature1,feature2,feature3¶
```¶

### Endpoint-specific headers¶

Some beta features are scoped to specific endpoints rather than individual request parameters and require a feature-specific beta header on every request:¶

| Endpoints | Beta header |¶
| --- | --- |¶
| `/v1/agents`, `/v1/sessions`, `/v1/environments` | `managed-agents-2026-04-01` |¶

See the [Managed Agents overview](/docs/en/managed-agents/overview) for details.¶

### Version naming conventions¶

Beta feature names typically follow the pattern: `feature-name-YYYY-MM-DD`, where the date indicates when the beta version was released. Always use the exact beta feature name as documented.¶

## Error handling¶

If you use an invalid or unavailable beta header, you'll receive an error response:¶

```json Output¶
{¶
"type": "error",¶
"error": {¶
"type": "invalid_request_error",¶
"message": "Unsupported beta header: invalid-beta-name"¶
}¶
}¶
```¶

## Getting help¶

For questions about beta features:¶

1. Check the documentation for the specific feature¶
2. Review the [API changelog](/docs/en/api/versioning) for updates¶
3. Contact support for assistance with production usage¶

Remember that beta features are provided "as-is" and may not have the same SLA guarantees as stable API features.

Unified Diff

--- a/api/beta-headers.md
+++ b/api/beta-headers.md
@@ -34,7 +34,7 @@
   -H "anthropic-beta: files-api-2025-04-14" \
   -H "content-type: application/json" \
   -d '{
-    "model": "claude-opus-4-7",
+    "model": "claude-opus-4-8",
     "max_tokens": 1024,
     "messages": [
       {"role": "user", "content": "Hello, Claude"}
@@ -45,7 +45,7 @@
 ```bash CLI
 ant beta:messages create \
   --beta files-api-2025-04-14 \
-  --model claude-opus-4-7 \
+  --model claude-opus-4-8 \
   --max-tokens 1024 \
   --message '{role: user, content: "Hello, Claude"}'
 ```
@@ -56,7 +56,7 @@
 client = Anthropic()
 
 response = client.beta.messages.create(
-    model="claude-opus-4-7",
+    model="claude-opus-4-8",
     max_tokens=1024,
     messages=[{"role": "user", "content": "Hello, Claude"}],
     betas=["files-api-2025-04-14"],
@@ -69,7 +69,7 @@
 const anthropic = new Anthropic();
 
 const msg = await anthropic.beta.messages.create({
-  model: "claude-opus-4-7",
+  model: "claude-opus-4-8",
   max_tokens: 1024,
   messages: [{ role: "user", content: "Hello, Claude" }],
   betas: ["files-api-2025-04-14"]