# Self-Healing CI: Auto-Retrying a uv Failed to Fetch from PyPI

> uv reporting "Failed to fetch" or "Failed to download" against PyPI is a transient transport failure. See the manual fix and how self-healing CI retries the resolve.

Source: https://latchkey.dev/learn/self-healing-ci/self-healing-uv-pypi-fetch-failure  
Updated: 2026-09-02

uv reporting "Failed to fetch" against pypi.org hit a transport failure, not a missing distribution: the same resolution succeeds on a retry.

## What makes a failure safely retryable

Automatic retry is only correct for failures that are genuinely transient. Retrying a deterministic failure wastes minutes and hides a real defect, so the classification matters more than the retry mechanism.

- Safe to retry: network timeouts, registry 5xx, transient DNS failures, a service container that was not ready, a spot instance reclaimed mid-run.
- Not safe to retry: assertion failures, compile errors, lint violations, anything that fails identically on every attempt.
- Ambiguous, and worth investigating rather than retrying: out-of-memory kills, disk exhaustion, and flaky tests. These repeat under load and a retry only hides the trend.
- Always record that a retry happened. A pipeline that silently retries is a pipeline whose real failure rate you do not know.

## FAQ

### Is this different from a pip network failure?

Same underlying cause, different frame. uv prints "Failed to fetch" or "Failed to download" with the URL, where pip prints a urllib3 exception or an HTTP status. Both are transport failures against the same hosts.

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Latchkey runs CI/CD that repairs its own failures. Agent entry points: https://latchkey.dev/agent.txt, https://latchkey.dev/openapi.json, https://latchkey.dev/llms.txt