fix: coalesce system messages into a single leading one at send time - #3
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Strict chat templates (Qwen among them) reject any request whose system message is not the single first message - Scaleway-hosted Qwen returns "API error (400): System message must be at the beginning". The extension violated that in three places: the per-turn auto-context note (inserted as a system message before the latest user turn), the agent path's "current active file" note (appended mid-transcript), and the agent transcript opening with two consecutive system messages when workspace orientation exists. ChatMessageNormalizer.CoalesceSystemMessages merges every system message (in order of appearance, blank-line joined) into one system message at index 0, leaving non-system messages and their tool-call metadata untouched. It runs at the request-build point in LLMService, so all chat, streaming, tool, and completion paths across every dialect are covered, and the persisted conversation history is never mutated. Fixes #2 Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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Summary
Fixes #2 — Scaleway-hosted Qwen rejects requests with
API error (400): "System message must be at the beginning."while Llama accepts the same payload. Qwen's chat template requires exactly one system message at position 0; the extension violated that in three places:ChatWindowControlsend): the per-turn auto-context (or no-solution note) was inserted as asystemmessage just before the latest user message — a mid-conversation system message on essentially every request.systemmessage.AgentLoop.NewTranscript): with workspace orientation present, the transcript started with two consecutive system messages — the second, at index 1, is "not at the beginning" for strict templates.Fix
ChatMessageNormalizer.CoalesceSystemMessagesmerges every system message (in order of appearance, joined by a blank line) into a single system message at index 0, leaving non-system messages — including tool-call metadata — untouched. It is applied at the request-build point inLLMService, so one code path covers chat, streaming, native-tool, and completion requests for every dialect. Permissive backends are unaffected; the persisted conversation history is never mutated (normalization is send-time only).This also removes an inconsistency where
TrimMessageHistoryalready hoisted system messages to the front, but only when trimming fired.Testing
New
tests/LocalModelIntegrator.Testsproject (the VSIX project can't be referenced from a plain test project, so the transport-format-free sources are compile-linked): 7 tests covering mid-conversation merge, double-leading-system merge, canonical/no-system passthrough, non-mutation of history, tool-call metadata preservation, and blank-system dropping. All written first and watched fail. VSIX project builds with 0 errors.🤖 Generated with Claude Code