providers: GitHub Copilot model sync never runs after login, no models listed #51928

Description

GitHub Copilot OAuth login succeeds and the account is stored, but no Copilot models ever appear in /models or opencode models. The model-list sync is never attempted after login: the server log contains no sync success or failure for the fresh login, only two historical entries:

2026-09-25 level=WARN message="failed to sync GitHub Copilot models" cause="TimeoutError: The operation timed out."
2026-09-26 level=WARN message="failed to sync GitHub Copilot models" cause="TimeoutError: The operation timed out."

Details:

• Fresh device-flow login completed today (github.com, Copilot Free plan): server log shows credential created ... integrationID=github-copilot type=oauth, and opencode auth list shows GitHub Copilot / GitHub Copilot / stored.
• After login: opencode models lists 154 models from other providers, 0 Copilot entries.
• opencode auth switch github-copilot "GitHub Copilot" reports success but triggers no sync (nothing new in the log) and no models.
• opencode service restart fires provider.updated / model.updated events but also triggers no sync.
• The sync endpoint is reachable from this machine (https://api.githubcopilot.com/models answers HTTP 400 unauthenticated, https://api.github.com answers 200), and the binary references https://api.githubcopilot.com, so this is not a general connectivity failure.

Note on possible duplicates: this may be related to #34644 (auto-only plans returning no model list — this account is on Copilot Free, not Student), but the symptom differs (V2 logs sync TimeoutErrors, then no sync attempts at all, rather than a silent drop / Provider not found). It differs from #38812 (V1, Pro/Pro+, model cache populated with 27 models but provider not surfacing — here no model list is ever fetched). Happy to consolidate if maintainers find the same root cause.

Plugins

None (no plugins directory; a third-party picker plugin was briefly tried and removed, unrelated)

OpenCode version

2.0.18 (channel latest, portable Windows build, background service)

Steps to reproduce

1. Run /connect in the TUI, select GitHub Copilot, complete the device flow on github.com (Copilot Free account).
2. Confirm opencode auth list shows the stored GitHub Copilot oauth account.
3. Run /models or opencode models — no copilot/* entries.
4. Run opencode auth switch github-copilot "GitHub Copilot" — succeeds, still no models, no sync in the log.
5. Run opencode service restart — still no models, no sync in the log.

Screenshot and/or share link

No response

Operating System

Windows 11 IoT Enterprise LTSC 10.0.26100 x64

Terminal

Windows Console Host (conhost), Windows PowerShell 5.1