Anthropic API / Anthropic API

Anthropic API SSE Stream 中断时状态码错误为 200 而非 529

修复 Anthropic Claude API 流式调用中 SSE 中断错误事件返回 HTTP 200 而非正确的 529 Overloaded 状态码的问题 Includes evidence for Anthropic API troubleshooting demand.

Source-backed Last updated May 16, 2026 4 sources Needs local verification

Category: Anthropic API
Error signature: APIStatusError: Status code 200 (expected 529) — mid-stream 'overloaded_error' event not properly mapped in streaming response
Quick fix: Reduce request pressure, check quota or plan limits, and retry with backoff instead of immediate repeated requests.
Updated: May 16, 2026
Verification status: Source-backed
Evidence: 4 public source URLs

Before you change production

This page includes public source URLs in the imported troubleshooting record. Compare those references with your version and environment before applying changes.

Reproduce the smallest failing action and save non-secret logs before changing configuration.
Check versions for Anthropic API, related SDKs, package managers, CI runners, and hosting providers.
Change one setting or dependency at a time, then rerun the same failing command or request.
Avoid destructive commands, credential rotation, billing changes, or security relaxations without a rollback plan.

What this error means

APIStatusError: Status code 200 (expected 529) — mid-stream 'overloaded_error' event not properly mapped in streaming response is a Anthropic API failure pattern reported for developers trying to 修复 anthropic claude api 流式调用中 sse 中断错误事件返回 http 200 而非正确的 529 overloaded 状态码的问题. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

anthropic-sdk-python #1258 明确描述：SSE 错误事件中 _streaming.py 传递原始 HTTP 200 response 给 _make_status_error，导致错误对象的 status_code 始终为 200。SDK 维护者已通过 PR #1262/#1263/#1269 逐步修复（https://github.com/anthropics/anthropic-sdk-python/issues/1258）。这是典型的 429/529 生产问题场景。Category mapping: 直接对应 Anthropic API。

Common causes

anthropic-sdk-python #1258 明确描述：SSE 错误事件中 _streaming.py 传递原始 HTTP 200 response 给 _make_status_error，导致错误对象的 status_code 始终为 200。SDK 维护者已通过 PR #1262/#1263/#1269 逐步修复（https://github.com/anthropics/anthropic-sdk-python/issues/1258）。这是典型的 429/529 生产问题场景。Category mapping: 直接对应 Anthropic API。

Quick fixes

Confirm the exact error signature matches APIStatusError: Status code 200 (expected 529) — mid-stream 'overloaded_error' event not properly mapped in streaming response.
Check the Anthropic API account, local tool state, and provider configuration involved in the failing workflow.
Reduce request pressure, check quota or plan limits, and retry with backoff instead of immediate repeated requests.

Platform/tool-specific checks

Verify the command, editor, extension, or API client that produced the error.
Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
Avoid deleting credentials, local model data, or project settings until the failing scope is clear.

Step-by-step troubleshooting

Capture the exact error message and the command, editor action, or request that triggered it.
Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
Review the source evidence below and compare it with your environment.
Apply one change at a time and rerun the smallest failing action.
Keep the working fix documented for the team or deployment environment.

How to prevent it

Keep provider/tool configuration documented.
Record non-secret diagnostics such as tool version, provider name, model name, and command path.
Add a lightweight check before CI or production workflows depend on the tool.

Diagnostic flow for this page

Match APIStatusError: Status code 200 (expected 529) — mid-stream 'overloaded_error' event not properly mapped in streaming response exactly before applying the quick fix.
Compare the failing environment with Anthropic API versions, account scope, provider settings, and deployment context.
Check the listed common causes in order, starting with the cause that best matches your logs.
Use the evidence status below to decide whether to confirm against public sources or official documentation.
Apply one reversible change, rerun the smallest failing action, and keep rollback notes.

FAQ

What does APIStatusError: Status code 200 (expected 529) — mid-stream 'overloaded_error' event not properly mapped in streaming response mean in Anthropic API?

APIStatusError: Status code 200 (expected 529) — mid-stream 'overloaded_error' event not properly mapped in streaming response indicates the workflow described by "Anthropic API SSE Stream 中断时状态码错误为 200 而非 529" failed in a Anthropic API context. Start by confirming the exact signature and the component that emitted it.

What should I check first for APIStatusError: Status code 200 (expected 529) — mid-stream 'overloaded_error' event not properly mapped in streaming response?

Check whether this cause matches your environment: anthropic-sdk-python #1258 明确描述：SSE 错误事件中 _streaming.py 传递原始 HTTP 200 response 给 _make_status_error，导致错误对象的 status_code 始终为 200。SDK 维护者已通过 PR #1262/#1263/#1269 逐步修复（https://github.com/anthropics/anthropic-sdk-python/issues/1258）。这是典型的 429/529 生产问题场景。Category mapping: 直接对应 Anthropic API。

Is the APIStatusError: Status code 200 (expected 529) — mid-stream 'overloaded_error' event not properly mapped in streaming response guidance source-backed?

The "Anthropic API SSE Stream 中断时状态码错误为 200 而非 529" page is labeled source-backed. It has 4 public source URLs from github.com, so use that evidence status when deciding how much additional verification you need.

When should I avoid the quick fix for APIStatusError: Status code 200 (expected 529) — mid-stream 'overloaded_error' event not properly mapped in streaming response?

For "Anthropic API SSE Stream 中断时状态码错误为 200 而非 529", avoid applying "Reduce request pressure, check quota or plan limits, and retry with backoff instead of immediate repeated requests." when the error text differs, the affected version or provider is different, or the change would touch credentials, billing, DNS, production deploy settings, or irreversible data.

What should I collect before debugging APIStatusError: Status code 200 (expected 529) — mid-stream 'overloaded_error' event not properly mapped in streaming response?

For "Anthropic API SSE Stream 中断时状态码错误为 200 而非 529", collect the failing Anthropic API command or request, non-secret configuration, versions, timestamps, request IDs when available, and the smallest reproduction that still triggers the signature.