Unblock PR One-line summary: Investigate a failing PR CI pipeline — attribute each failure as flaky, infra, or regression and propose a targeted action. Requires: skill (pup CLI installed and authenticated), skill (for flaky failure deep investigation). --- Backend Detection — At the start of every invocation, before taking any action, determine which backend to use: 1. If the user passed anywhere → use pup mode immediately. Skip steps 2–4. 2. Check whether appears in your available tools. 3. If present → use MCP mode throughout. Call tools exactly as named in this skill's workflow sections.…