OpenAI API / OpenAI API

OpenAI Python SDK streaming tool_call deltas with duplicate indexes accumulated incorrectly

Fix broken tool call streaming when first chunk contains duplicate index entries in OpenAI Python SDK Includes evidence for OpenAI API troubleshooting demand.

Source-backed Last updated May 16, 2026 1 source Needs local verification

Category: OpenAI API
Error signature: Streaming tool_call deltas with duplicate indexes in first chunk are accumulated incorrectly — accumulate_delta assumes index matches physical list position
Quick fix: Compare the failing environment with a known working setup, then change one configuration value at a time.
Updated: May 16, 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 OpenAI 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

Streaming tool_call deltas with duplicate indexes in first chunk are accumulated incorrectly — accumulate_delta assumes index matches physical list position is a OpenAI API failure pattern reported for developers trying to fix broken tool call streaming when first chunk contains duplicate index entries in openai python sdk. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

Bug in openai-python accumulate_delta: when first streamed chunk has multiple tool_calls with same index, accumulator stores list directly and later chunks merge into wrong entry. Results in invalid JSON and stranded tool call arguments. Category: OpenAI API.

Common causes

Bug in openai-python accumulate_delta: when first streamed chunk has multiple tool_calls with same index, accumulator stores list directly and later chunks merge into wrong entry. Results in invalid JSON and stranded tool call arguments. Category: OpenAI API.

Quick fixes

Confirm the exact error signature matches Streaming tool_call deltas with duplicate indexes in first chunk are accumulated incorrectly — accumulate_delta assumes index matches physical list position.
Check the OpenAI 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 Streaming tool_call deltas with duplicate indexes in first chunk are accumulated incorrectly — accumulate_delta assumes index matches physical list position exactly before applying the quick fix.
Compare the failing environment with OpenAI 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 Streaming tool_call deltas with duplicate indexes in first chunk are accumulated incorrectly — accumulate_delta assumes index matches physical list position mean in OpenAI API?

Streaming tool_call deltas with duplicate indexes in first chunk are accumulated incorrectly — accumulate_delta assumes index matches physical list position indicates the workflow described by "OpenAI Python SDK streaming tool_call deltas with duplicate indexes accumulated incorrectly" failed in a OpenAI API context. Start by confirming the exact signature and the component that emitted it.

What should I check first for Streaming tool_call deltas with duplicate indexes in first chunk are accumulated incorrectly — accumulate_delta assumes index matches physical list position?

Check whether this cause matches your environment: Bug in openai-python accumulate_delta: when first streamed chunk has multiple tool_calls with same index, accumulator stores list directly and later chunks merge into wrong entry. Results in invalid JSON and stranded tool call arguments. Category: OpenAI API.

Is the Streaming tool_call deltas with duplicate indexes in first chunk are accumulated incorrectly — accumulate_delta assumes index matches physical list position guidance source-backed?

The "OpenAI Python SDK streaming tool_call deltas with duplicate indexes accumulated incorrectly" 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 Streaming tool_call deltas with duplicate indexes in first chunk are accumulated incorrectly — accumulate_delta assumes index matches physical list position?

For "OpenAI Python SDK streaming tool_call deltas with duplicate indexes accumulated incorrectly", 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 Streaming tool_call deltas with duplicate indexes in first chunk are accumulated incorrectly — accumulate_delta assumes index matches physical list position?

For "OpenAI Python SDK streaming tool_call deltas with duplicate indexes accumulated incorrectly", collect the failing OpenAI API command or request, non-secret configuration, versions, timestamps, request IDs when available, and the smallest reproduction that still triggers the signature.