Anthropic API / Anthropic API

Anthropic SDK Mid-Stream Transport Error Leaks as Bare httpx.Exception Instead of APIConnectionError

Developer using Anthropic streaming API loses connection mid-stream (TransportError) and can't catch it with standard except anthropic.APIConnectionError blocks — must know to also catch httpx.TransportError Includes evidence for Anthropic API troubleshooting demand.

Source-backed Last updated May 17, 2026 1 source Needs local verification

Category: Anthropic API
Error signature: Mid-stream httpx.TransportError leaks through as bare httpx exceptions because SSE body iteration has no try/except — customers standard retry ladder misses mid-stream drops
Quick fix: Compare the failing environment with a known working setup, then change one configuration value at a time.
Updated: May 17, 2026
Verification status: Source-backed
Evidence: 1 public source URL

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

Mid-stream httpx.TransportError leaks through as bare httpx exceptions because SSE body iteration has no try/except — customers standard retry ladder misses mid-stream drops is a Anthropic API failure pattern reported for developers trying to developer using anthropic streaming api loses connection mid-stream (transporterror) and can't catch it with standard except anthropic.apiconnectionerror blocks — must know to also catch httpx.transporterror. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

Found on anthropics/anthropic-sdk-python/pull/1552 (open PR, 2026-05-16, fix proposed). Streaming SSE errors during body iteration cause crashes outside SDK error wrapping. Developers lose streamed content without catching unexpected exception types. Critical for paid API users building production apps. Maps to Anthropic API (approved category).

Common causes

Found on anthropics/anthropic-sdk-python/pull/1552 (open PR, 2026-05-16, fix proposed). Streaming SSE errors during body iteration cause crashes outside SDK error wrapping. Developers lose streamed content without catching unexpected exception types. Critical for paid API users building production apps. Maps to Anthropic API (approved category).

Quick fixes

Confirm the exact error signature matches Mid-stream httpx.TransportError leaks through as bare httpx exceptions because SSE body iteration has no try/except — customers standard retry ladder misses mid-stream drops.
Check the Anthropic API account, local tool state, and provider configuration involved in the failing workflow.
Compare the failing environment with a known working setup, then change one configuration value at a time.

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 Mid-stream httpx.TransportError leaks through as bare httpx exceptions because SSE body iteration has no try/except — customers standard retry ladder misses mid-stream drops 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 Mid-stream httpx.TransportError leaks through as bare httpx exceptions because SSE body iteration has no try/except — customers standard retry ladder misses mid-stream drops mean in Anthropic API?

Mid-stream httpx.TransportError leaks through as bare httpx exceptions because SSE body iteration has no try/except — customers standard retry ladder misses mid-stream drops indicates the workflow described by "Anthropic SDK Mid-Stream Transport Error Leaks as Bare httpx.Exception Instead of APIConnectionError" failed in a Anthropic API context. Start by confirming the exact signature and the component that emitted it.

What should I check first for Mid-stream httpx.TransportError leaks through as bare httpx exceptions because SSE body iteration has no try/except — customers standard retry ladder misses mid-stream drops?

Check whether this cause matches your environment: Found on anthropics/anthropic-sdk-python/pull/1552 (open PR, 2026-05-16, fix proposed). Streaming SSE errors during body iteration cause crashes outside SDK error wrapping. Developers lose streamed content without catching unexpected exception types. Critical for paid API users building production apps. Maps to Anthropic API (approved category).

Is the Mid-stream httpx.TransportError leaks through as bare httpx exceptions because SSE body iteration has no try/except — customers standard retry ladder misses mid-stream drops guidance source-backed?

The "Anthropic SDK Mid-Stream Transport Error Leaks as Bare httpx.Exception Instead of APIConnectionError" page is labeled source-backed. It has 1 public source URL from github.com, so use that evidence status when deciding how much additional verification you need.

When should I avoid the quick fix for Mid-stream httpx.TransportError leaks through as bare httpx exceptions because SSE body iteration has no try/except — customers standard retry ladder misses mid-stream drops?

For "Anthropic SDK Mid-Stream Transport Error Leaks as Bare httpx.Exception Instead of APIConnectionError", avoid applying "Compare the failing environment with a known working setup, then change one configuration value at a time." 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 Mid-stream httpx.TransportError leaks through as bare httpx exceptions because SSE body iteration has no try/except — customers standard retry ladder misses mid-stream drops?

For "Anthropic SDK Mid-Stream Transport Error Leaks as Bare httpx.Exception Instead of APIConnectionError", 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.