[Sohom chakraborty (sohom-cs)]

Motivation & Context

None of the three approaches in python/samples/02-agents/auto_retry.py retries a 429. They retry on retry_if_exception_type(openai.RateLimitError), but the chat clients raise ChatClientException with the RateLimitError on __cause__, so the predicate never matches. Reproduction in #9904.

Description & Review Guide

• What are the major changes? Add is_rate_limit_error(), which matches a ChatClientException whose __cause__ is an openai.RateLimitError, and use it through retry_if_exception in all three approaches. The docstrings now say what is retried.
• What is the impact of these changes? Sample only. With FoundryChatClient on a mock transport (429, then 200; SDK retries off), each approach now retries and returns the response instead of raising on the first 429. A 400 is still not retried. There are no tests for these samples, so none are added. Not tested against a live rate limit or with streaming.
• What do you want reviewers to focus on? Whether checking __cause__ is how you want the sample to show this. The predicate requires ChatClientException, so a bare RateLimitError is not retried.

Related Issue

Fixes #9904

AI Assistance

• No material AI assistance was used.
• This is an AI-assisted contribution. I reviewed, understood, and verified all submitted content and accept responsibility for it.

AI assistance details: Claude Code helped with the issue analysis, the reproduction, the change, and this description. I ran the reproduction before and after the change.

Contribution Checklist

• The code builds clean without any errors or warnings
• All unit tests pass, and I have added new tests where possible
• The PR follows the Contribution Guidelines
• This PR links to an agreed issue with no competing open PR, or the Related Issue section documents a trivial-change or repository-automation exception.
• This is not a breaking change. If it is a breaking change, add the breaking change label (or add "[BREAKING]" to the title prefix, before or after any language prefix) — a workflow keeps the label and title prefix in sync automatically.

[Sohom chakraborty (sohom-cs)]

@microsoft-github-policy-service agree

[Copilot]

🟢 Approval recommended

No active review issues are reported for the update to handle wrapped rate-limit errors across all three retry implementations.

No open issues 🎉

What changed in this PR

Fixes the Python auto-retry sample for #9904 by recognizing OpenAI rate-limit errors wrapped in ChatClientException, allowing the sample’s retry layer to handle 429 responses.

Changes:

• Adds a shared predicate that checks the exception type and its __cause__.
• Applies the predicate to all three retry implementations.
• Updates documentation to explain wrapped errors and retry behavior.

File	Description
python/​samples/​02-agents/​auto_retry.py	Corrects rate-limit detection across all retry approaches and clarifies documentation.

_{Review effort: Balanced}