[FEATURE] 529 overloaded_error message is confusing — users think it's their own machine struggling

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

When Claude Code hits a 529 from the Anthropic API, it shows the raw JSON:

529 {"type":"error","error":{"type":"overloaded_error","message":"Overloade
"},"request_id":"req_011CXYYF8iKb9TFwRRrbeR2A"}
Retrying in 0 seconds… (attempt 4/10)

This doesn't make it clear the issue is on Anthropic's side. I assumed my VM
was out of resources and spent time debugging locally before realising it was
just API capacity.

Proposed Solution

Replace with a human-readable message like:

Anthropic API is temporarily overloaded (529). Retrying… (attempt 4/10)

Makes it immediately obvious that: (1) the problem is server-side, not local,
(2) no local action needed, (3) retries are automatic.

Alternative Solutions

_No response_

Priority

Critical - Blocking my work

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_