flake: TestPatchChatMessage/ChangesModel

[flake-investigator]

CI Run: https://github.com/coder/coder/actions/runs/25735831236
Failed Jobs:

• test-go-race-pg: https://github.com/coder/coder/actions/runs/25735831236/job/75573198495
• test-go-pg (ubuntu-latest): https://github.com/coder/coder/actions/runs/25735831236/job/75573198542
• test-go-pg-17: https://github.com/coder/coder/actions/runs/25735831236/job/75573198496

Commit: 96333acda3f67a96b84c3ed3be055c993bfe86ad (Michael Suchacz)
coder/coder@96333ac

Failing test:

• Package: coderd
• Test: TestPatchChatMessage/ChangesModel
• File: coderd/exp_chats_test.go (subtest around ~7265)

Failure excerpt:

exp_chats_test.go:7290:
    Error:      Received unexpected error:
                POST http://127.0.0.1:38435/api/experimental/chats/model-configs: unexpected status code 400: Chat provider is not configured.
                Error: execute transaction: chat provider is not configured
    Test:       TestPatchChatMessage/ChangesModel

(Same error in test-go-race-pg and test-go-pg-17.)

Error analysis / root cause:

• The ChangesModel subtest creates an additional model config with provider "openai" via createAdditionalChatModelConfig, but the chat test harness now configures only the "openai-compat" provider (via coderdtest.FakeOpenAICompatProviderAPIKeys). The model config create request fails with HTTP 400 "Chat provider is not configured".
• This appears deterministic across race/non-race jobs in the same run.
• No data race warnings, panics, or OOM indicators observed in the logs (searched for "WARNING: DATA RACE", "panic:", "out of memory").

Assignment analysis:

• Intended blame command: git blame -L 7265,7345 coderd/exp_chats_test.go (ChangesModel subtest).
• File history via API: git log --oneline -10 --follow coderd/exp_chats_test.go shows the most recent substantive change adding this subtest in commit f1d160c7 ("fix: allow changing model when editing earlier chat message") by @ibetitsmike.
• Assigning to @ibetitsmike as the most recent meaningful modifier of this test area. Please reassign if ownership differs.

Related issues searched (no direct matches):

• "TestPatchChatMessage", "Chat provider is not configured", "exp_chats_test.go"
• Similar but different failures in the same file: flake: TestListChats/PinnedOnFirstPage #1507, flake: TestPatchChat/Title (multiple variants) #1480.

Reproduction (best effort):

go test ./coderd -run TestPatchChatMessage/ChangesModel -count=1