# US-020 — Tracker + node hardening: BrokenPipe fix, deterministic node IDs, HF coverage

Status: done
Priority: High
Stage: Maintenance

## Context

First two-machine LAN test (US-018) exposed three reliability issues:

1. `BrokenPipeError` crash in tracker `_send_json` when a slow-inference client disconnected mid-response
2. Random UUID node IDs meant every re-registration (after tracker restart) created a phantom entry
3. `GET /v1/coverage/<model>` returned no results when called with a short name (`Qwen2.5-0.5B`) instead of the full HF repo ID

## Acceptance criteria

- [ ] `BrokenPipeError` in tracker and node `_send_json` is silently swallowed
- [ ] Node IDs are deterministic: `sha256(wallet_address + str(port))[:16]`
- [ ] `GET /v1/coverage/<model>` accepts both short names and full `owner/repo` IDs
- [ ] `python -m pytest` passes from repo root
